subject:"\[time\-nuts\] LTE\-Lite module"

Hi

We tend to focus on this or that enhanced feature in a piece of code. It’s fun 
to talk about. That’s not what keeps most designs from doing what they should. 
By focusing on this rather than the testing required, we set people up to fail. 
If you start off the project believing you mostly need fancy code when you 
mostly need long term testing instead, you hit a wall pretty fast. Setting up 
for one is not at all the same as setting up for the other. 

Bob

 On Oct 20, 2014, at 5:51 AM, Charles Steinmetz csteinm...@yandex.com wrote:
 
 Poul-Henning wrote:
 
 PLLs are really not that hard  [context: we have been discussing all-digital 
 PLLs (ADPLLs)]
 
 Yes, I know -- I have designed more than a few.  I have also reviewed more 
 than a dozen hobbyist designs and modeled some of them, and found that few 
 hobbyists seem to have mastered the art.  Judging also by on-list responses 
 over the years, it does not appear that many time nuts are interested in 
 designing and building their own ADPLLs.  So, I conclude that disciplining a 
 good OCXO with GPS and getting the best stability the OCXO can deliver is not 
 practicable for most hobbyists.
 
 The OP in this sub-thread indicated that he was considering using an LTE-Lite 
 to discipline a really good 10811, and it appeared that his expectation was 
 to end up with a GPSDO more or less as good as his 10811.  My point was 
 simply to put realistic bounds on the expectation.
 
 Said posted that a quick lash-up with an OCXO produced stability about 10x 
 better than with the on-board TCXO.  That is a useful improvement, but a good 
 OCXO (certainly, a really good 10811) will have stability about 3 orders of 
 magnitude better than a TCXO (1000x), so two decades of possible improvement 
 were not realized.
 
 Said's experiment was a proof-of-concept exercise and not a careful 
 optimization, so it is almost certain one could do better than 10x with some 
 further work.  But I very much doubt that optimization can gain the entire 
 two decades of potential improvement (short of designing a full ADPLL, in 
 which case you don't need the LTE-Lite at all -- all you need is a source of 
 PPS), and I doubt it is possible to gain even one whole decade.
 
 So, I am inclined to think that there are better (and easier) ways to 
 discipline a 10811 to reach its ful potential, that's all.
 
 Best regards,
 
 Charles
 
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Charles Steinmetz


Bob wrote:

We tend to focus on this or that enhanced feature in a piece of 
code. It's fun to talk about. That's not what keeps most designs 
from doing what they should. By focusing on this rather than the 
testing required, we set people up to fail. If you start off the 
project believing you mostly need fancy code when you mostly need 
long term testing instead, you hit a wall pretty fast. Setting up 
for one is not at all the same as setting up for the other.


Not really sure what this has to do with my post to which you 
replied??  I assure you, I do not find code to be a fun, or even very 
interesting, topic of conversation, and I did not mention it at all 
in that post.  Really, the only thing I've said about code is that 
I've found it takes more than 100 lines to do a proper ADPLL.  When I 
have some time, I have to sit down and study Poul-Henning's code to 
see what I can learn from it about parsimony.


Best regards,

Charles



___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Tom Van Baak

 http://phk.freebsd.dk/time/20141018.html

PHK,

This is the best news I've heard in a long time; an overhaul of NTP!

One suggestion I'd like to make. You've seen the GPSDO simulator code I started:
http://leapsecond.com/tools/gpsim1.c
And you've seen the growing collection of GPS receiver and OCXO oscillator raw 
data:
http://leapsecond.com/pages/gpsdo-sim/

Instead of tweaking GPSDO algorithms or tuning parameters and having to wait 
days to see if it works or not, the idea was to replay pre-recorded 1PPS data 
and pre-recorded oscillator data into the PLL. This means one can test any new 
design change in a GPSDO in a matter of seconds instead of days.

So the question is -- could you do the same for NTP? On your own, or with 
world-wide contributions, you could collect long data sets (phase or frequency) 
of free-running PC clock oscillators, every shape and size and environment. And 
then also collect high-precision real-life NTP packet timings, warts and all 
(especially outlier examples).

Then instead of testing iterations of your new code on live NTP servers you 
merely apply previously collected packet data and previously collected clock 
data. With a little scripting you'd get performance plots within seconds 
instead of waiting hours or days. Moreover, the plots you generate would cover 
tens or hundreds of historical scenarios instead of just the few you could find 
in real time.

/tvb

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Brian Lloyd

On Mon, Oct 20, 2014 at 6:48 AM, Bob Camp kb...@n1k.org wrote:

 Hi

 We tend to focus on this or that enhanced feature in a piece of code. It’s
 fun to talk about. That’s not what keeps most designs from doing what they
 should. By focusing on this rather than the testing required, we set people
 up to fail. If you start off the project believing you mostly need fancy
 code when you mostly need long term testing instead, you hit a wall pretty
 fast. Setting up for one is not at all the same as setting up for the other.


Sounds to me like the hardware and code are pretty straight-forward. The
difference comes from the terms and coefficients in the PLL loop filter and
those need to be optimized for each OCXO. There appear to be here a handful
of people who have a pretty good idea of what those coefficients should be
for various well-known OCXOs out there.

So why not do the GPSD hardware, software, and then provide the
coefficients that will get a handful of the more popular OCXOs available
out there to within a decade of optimum, certainly closer than what one
would be talking about by just bolting x-random OCXO onto an LTE-lite? I
suspect there would be a market in the time-nut world for such a critter.

-- 
Brian Lloyd
Lloyd Aviation
706 Flightline Drive
Spring Branch, TX 78070
br...@lloyd.aero
+1.210.802-8FLY (1.210.802-8359)
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Poul-Henning Kamp


In message 60CC0E034928B664249EAC88407F@pc52, Tom Van Baak writes:
 http://phk.freebsd.dk/time/20141018.html

PHK,

This is the best news I've heard in a long time; an overhaul of NTP!

Indeed :-)

Instead of tweaking GPSDO algorithms or tuning parameters and
having to wait days to see if it works or not, the idea was to
replay pre-recorded 1PPS data and pre-recorded oscillator data
into the PLL. This means one can test any new design change in a
GPSDO in a matter of seconds instead of days.

So the question is -- could you do the same for NTP?

Well, first of all it's not days any longer.  My proto-PLL wrangles
the clock phase in a matter of seconds and frequency in a few
minutes.  Some of the (really) old NTP assumptions and metrics no
longer hold, revisiting them opens up a lot of parameter space.

Second, I'm already doing such simulations, and the ability to
do that is part of the design basis of what I'm doing.

I spent a month of my NTP-time trying to resurrect the SIM code in
ntpd, in order to get some kind of reproducible test-bench going and
in the end I concluded that 100k lines of code is not the way forward.

My current plan is to release a brand new client-only NTP daemon
with a decent PLL and high attack resistance before X-mas and then
work from there to one or two other programs: NTP-slave server (ie:
stratum 2..14) and a NTP-master/stratum 1 server.

All along the way, the intent is to try to pull PTP into this also,
since there is no material (ie: only protocol) difference between
a NTP and PTP timekeeping program, and the user shouldn't need to
notice the difference.

More as it happens.

The mini-blog entries I've started will happen every so often
when there is some progress to report or interesting data to
present.


-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Poul-Henning Kamp


In message CAGVVbuGv_-cFDAA=T6hGE1ey32=omxxcg-cxub5scusao_t...@mail.gmail.com
, Brian Lloyd writes:

So why not do the GPSD hardware, software, [...]

It would be a really worthwhile project in general, and it could be
made very general with very little trouble.

I would find a cheap ARM board (Olimex ?) that can support ChibiOS:

http://www.chibios.org/dokuwiki/doku.php?id=news

and add a cape PCB with a high resolution DAC for EFC control
and two phase detectors, one for 100kHz-20MHz frequencies and one
for 1-100Hz frequencies.  (The latter could have a TVB PIC divider
as an option on the reference input).

Maybe add a couple of isolated distribution amp outputs also ?

That would make for a really experimenter-friendly computer PLL
platform.

People who want to code can do so, people less ambitious could
tweak PLL params in the default firmware using the ChibiOS command
line interface...

Count me in...


-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread S. Jackson via time-nuts

Hi Brian, Bob, Charles, et. al.
 
Bob has a great point about the difference between a one-off in a basement  
lab, and a commercial product that has to work under any circumstances, 
wether  flying at 50,000 feet at -56C, or in an urban canyon, or under whatever 
other  stress could be thrown at it. In fact the testing and fine tuning 
does take  90% of a product design cycle.
 
That said here is the ADEV plot from my overnight test with the DOCXO. No  
comments.
 
This was done without any loop adjustment whatsoever, same board and  
software that drives the on-board TCXO. I will let the result speak for  
itself, 
save to say the loop, the DAC, the DAC reference, and the GPS with a  proper 
OCXO can achieve performance at a level approaching two orders of  
magnitude better than our spec which is 1ppb for this  particular product.
 
PLEASE(!) do not send me emails once you get your board and plug in your  
own OCXO and don't see similar performance for whatever reasons. There is not 
 much we can do about that, other than say our product meets 
specifications. On  the other hand if you connect a really good OCXO you may 
even get 
better  performance than I got, but who knows.

Thanks,
Said
 
 
 
 
In a message dated 10/20/2014 10:21:15 Pacific Daylight Time,  
br...@lloyd.aero writes:

On Mon,  Oct 20, 2014 at 6:48 AM, Bob Camp kb...@n1k.org wrote:

  Hi

 We tend to focus on this or that enhanced feature in a  piece of code. It’
s
 fun to talk about. That’s not what keeps most  designs from doing what 
they
 should. By focusing on this rather than  the testing required, we set 
people
 up to fail. If you start off the  project believing you mostly need fancy
 code when you mostly need long  term testing instead, you hit a wall 
pretty
 fast. Setting up for one  is not at all the same as setting up for the 
other.


Sounds to  me like the hardware and code are pretty straight-forward. The
difference  comes from the terms and coefficients in the PLL loop filter and
those need  to be optimized for each OCXO. There appear to be here a handful
of people  who have a pretty good idea of what those coefficients should be
for  various well-known OCXOs out there.

So why not do the GPSD hardware,  software, and then provide the
coefficients that will get a handful of the  more popular OCXOs available
out there to within a decade of optimum,  certainly closer than what one
would be talking about by just bolting  x-random OCXO onto an LTE-lite? I
suspect there would be a market in the  time-nut world for such a critter.

-- 
Brian Lloyd
Lloyd  Aviation
706 Flightline Drive
Spring Branch, TX  78070
br...@lloyd.aero
+1.210.802-8FLY  (1.210.802-8359)
___
time-nuts  mailing list -- time-nuts@febo.com
To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the  instructions there.


lte-lite_DOCXO_adev.png
Description: Binary data
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Hi

PHK has a roughly 6 line code snippet that does a basic PLL. Add two more lines 
to check / clamp the integrator if you wish. That’s 8 lines. If you want a D 
term (to give it an FLL component) add 2 more lines. We’re up to 10 lines. 

It’s just a control loop, not a full GPSDO. There’s not a lot to it.

The code and some magic hardware to run it on is not the key to all this. 
Setting up and spending the time testing and optimizing is.

Bob

 On Oct 20, 2014, at 8:54 AM, Charles Steinmetz csteinm...@yandex.com wrote:
 
 Bob wrote:
 
 We tend to focus on this or that enhanced feature in a piece of code. It's 
 fun to talk about. That's not what keeps most designs from doing what they 
 should. By focusing on this rather than the testing required, we set people 
 up to fail. If you start off the project believing you mostly need fancy 
 code when you mostly need long term testing instead, you hit a wall pretty 
 fast. Setting up for one is not at all the same as setting up for the other.
 
 Not really sure what this has to do with my post to which you replied??  I 
 assure you, I do not find code to be a fun, or even very interesting, topic 
 of conversation, and I did not mention it at all in that post.  Really, the 
 only thing I've said about code is that I've found it takes more than 100 
 lines to do a proper ADPLL.  When I have some time, I have to sit down and 
 study Poul-Henning's code to see what I can learn from it about parsimony.
 
 Best regards,
 
 Charles
 
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Hi

The problem is that there are no “magic coefficients”. What you run depends 
very much on the exact OCXO you have, the environment you run it in, and the 
result you are after. 

For instance, Bert is after frequency stability. Tom is after the right time. 
Each of them will have very different coefficients for the same oscillator. 

My Morion OCXO has a floor of 2x10^-12, Bert has some that are 10X better than 
that (maybe). His coefficients and mine will be very different. 

I had an antenna outdoors. It got many sat’s all the time. Now I have one 
indoors. It’s not getting lots of sats all the time. My old coefficients are 
not going to be my new coefficients. 

No magic bullet, you have to do the work. 

Bob

 On Oct 20, 2014, at 1:20 PM, Brian Lloyd br...@lloyd.aero wrote:
 
 On Mon, Oct 20, 2014 at 6:48 AM, Bob Camp kb...@n1k.org wrote:
 
 Hi
 
 We tend to focus on this or that enhanced feature in a piece of code. It’s
 fun to talk about. That’s not what keeps most designs from doing what they
 should. By focusing on this rather than the testing required, we set people
 up to fail. If you start off the project believing you mostly need fancy
 code when you mostly need long term testing instead, you hit a wall pretty
 fast. Setting up for one is not at all the same as setting up for the other.
 
 
 Sounds to me like the hardware and code are pretty straight-forward. The
 difference comes from the terms and coefficients in the PLL loop filter and
 those need to be optimized for each OCXO. There appear to be here a handful
 of people who have a pretty good idea of what those coefficients should be
 for various well-known OCXOs out there.
 
 So why not do the GPSD hardware, software, and then provide the
 coefficients that will get a handful of the more popular OCXOs available
 out there to within a decade of optimum, certainly closer than what one
 would be talking about by just bolting x-random OCXO onto an LTE-lite? I
 suspect there would be a market in the time-nut world for such a critter.
 
 -- 
 Brian Lloyd
 Lloyd Aviation
 706 Flightline Drive
 Spring Branch, TX 78070
 br...@lloyd.aero
 +1.210.802-8FLY (1.210.802-8359)
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Hi

The top of my list for “new NTP” would be to bring the 1588 hardware packet 
time tagging into the NTP code base. There’s a pretty good base of hardware out 
there that tags. It should help things on a loaded system.

Bob

 On Oct 20, 2014, at 3:41 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
 
 
 In message 60CC0E034928B664249EAC88407F@pc52, Tom Van Baak writes:
 http://phk.freebsd.dk/time/20141018.html
 
 PHK,
 
 This is the best news I've heard in a long time; an overhaul of NTP!
 
 Indeed :-)
 
 Instead of tweaking GPSDO algorithms or tuning parameters and
 having to wait days to see if it works or not, the idea was to
 replay pre-recorded 1PPS data and pre-recorded oscillator data
 into the PLL. This means one can test any new design change in a
 GPSDO in a matter of seconds instead of days.
 
 So the question is -- could you do the same for NTP?
 
 Well, first of all it's not days any longer.  My proto-PLL wrangles
 the clock phase in a matter of seconds and frequency in a few
 minutes.  Some of the (really) old NTP assumptions and metrics no
 longer hold, revisiting them opens up a lot of parameter space.
 
 Second, I'm already doing such simulations, and the ability to
 do that is part of the design basis of what I'm doing.
 
 I spent a month of my NTP-time trying to resurrect the SIM code in
 ntpd, in order to get some kind of reproducible test-bench going and
 in the end I concluded that 100k lines of code is not the way forward.
 
 My current plan is to release a brand new client-only NTP daemon
 with a decent PLL and high attack resistance before X-mas and then
 work from there to one or two other programs: NTP-slave server (ie:
 stratum 2..14) and a NTP-master/stratum 1 server.
 
 All along the way, the intent is to try to pull PTP into this also,
 since there is no material (ie: only protocol) difference between
 a NTP and PTP timekeeping program, and the user shouldn't need to
 notice the difference.
 
 More as it happens.
 
 The mini-blog entries I've started will happen every so often
 when there is some progress to report or interesting data to
 present.
 
 
 -- 
 Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
 p...@freebsd.org | TCP/IP since RFC 956
 FreeBSD committer   | BSD since 4.3-tahoe
 Never attribute to malice what can adequately be explained by incompetence.
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Bert Kehren via time-nuts

Allow me to clarify.
I started out with 7 MV 89 one of it a total loss. The remaining 6 after 3  
month +  burn in show better than 1 E-11 aging per day, 2 closer to 5 E-12. 
 Only two have been tested for ADEV and are close to 1 E-12,  2X not 10  X.
Bert Kehren
 
 
In a message dated 10/20/2014 5:58:37 P.M. Eastern Daylight Time,  
kb...@n1k.org writes:

Hi

The  problem is that there are no “magic coefficients”. What you run 
depends very  much on the exact OCXO you have, the environment you run it in, 
and 
the result  you are after. 

For instance, Bert is after frequency stability. Tom is  after the right 
time. Each of them will have very different coefficients for  the same 
oscillator. 

My Morion OCXO has a floor of 2x10^-12, Bert has  some that are 10X better 
than that (maybe). His coefficients and mine will be  very different. 

I had an antenna outdoors. It got many sat’s all the  time. Now I have one 
indoors. It’s not getting lots of sats all the time. My  old coefficients 
are not going to be my new coefficients. 

No magic  bullet, you have to do the work. 

Bob

 On Oct 20, 2014, at  1:20 PM, Brian Lloyd br...@lloyd.aero wrote:
 
 On Mon,  Oct 20, 2014 at 6:48 AM, Bob Camp kb...@n1k.org wrote:
  
 Hi
 
 We tend to focus on this or that  enhanced feature in a piece of code. It
’s
 fun to talk about.  That’s not what keeps most designs from doing what 
they
 should. By  focusing on this rather than the testing required, we set 
people
  up to fail. If you start off the project believing you mostly need  
fancy
 code when you mostly need long term testing instead, you hit  a wall 
pretty
 fast. Setting up for one is not at all the same as  setting up for the 
other.
 
 
 Sounds to me like the  hardware and code are pretty straight-forward. The
 difference comes  from the terms and coefficients in the PLL loop filter 
and
 those need  to be optimized for each OCXO. There appear to be here a 
handful
 of  people who have a pretty good idea of what those coefficients should  
be
 for various well-known OCXOs out there.
 
 So why not  do the GPSD hardware, software, and then provide the
 coefficients that  will get a handful of the more popular OCXOs available
 out there to  within a decade of optimum, certainly closer than what one
 would be  talking about by just bolting x-random OCXO onto an LTE-lite? I
  suspect there would be a market in the time-nut world for such a  
critter.
 
 -- 
 Brian Lloyd
 Lloyd  Aviation
 706 Flightline Drive
 Spring Branch, TX 78070
  br...@lloyd.aero
 +1.210.802-8FLY (1.210.802-8359)
  ___
 time-nuts mailing list  -- time-nuts@febo.com
 To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the  instructions  there.

___
time-nuts  mailing list -- time-nuts@febo.com
To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the  instructions there.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread S. Jackson via time-nuts

Thanks much Charles,
 
just to remind everyone that the main idea of making the boards  available 
was to get folks a good disciplined TCXO, not to work as a  development 
platform to discipline external OCXOs.. Also as mentioned in the  FAQ, the 
typical performance plots I have been sending and are also in the  user-manual 
are gathered under optimal conditions of course: a roof-top antenna,  units 
shielded from airflow, and units running for a couple of days before  testing.
 
Please also note that I tried an OCXO with only +/-2Hz EFC range and  it 
did not lock due to the ~10Ks resulting time-constant and the loop being way  
to slow to capture the OCXO..
 
External oscillators should have between 9Hz per Volt to 100Hz+ per  Volt 
EFC sensitivity from what I can tell, otherwise an OPAMP circuit would be  
needed to bring the EFC into that range. Sorry, I cannot propose such a 
circuit,  but such a circuit had been sent as a schematic to the time nuts some 
 
years ago by someone if I remember correctly.
 
Bye,
Said
 
 
In a message dated 10/20/2014 15:55:45 Pacific Daylight Time,  
csteinm...@yandex.com writes:


here is the ADEV plot from my overnight test with the  DOCXO.  *  *  *

This was done without any loop  adjustment whatsoever, same board and
software that drives the on-board  TCXO. I will let the result speak 
for  itself,
save to say  the loop, the DAC, the DAC reference, and the GPS with a   
proper
OCXO can achieve performance at a level approaching two orders  of
magnitude better than our spec which is 1ppb for this   particular product.

Thanks for the ADEV plot, Said -- more pertinent  for most time nuts 
purposes than PN.  Of course, the typical  performance of the LTE-Lite 
with the TCXO is significantly better than the  spec (according to the 
user manual, about 5e-11 at 1 second and 1e-10 at  10 seconds, already 
1 to 1.5 OOM better than spec), so the typical  improvement with the 
OCXO wouldn't be a full two orders of  magnitude.  Still, very 
noteworthy performance that *surely*  justifies time nuts in buying 
one of the good, cheap OCXOs flooding the  surplus market to go along 
with their LTE-Lite.  Good  show.

Best  regards,

Charles



___
time-nuts  mailing list -- time-nuts@febo.com
To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the  instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Tom Van Baak

To add to Bert's note...

Realize that for a GPSDO, (linear frequency) aging-per-day is irreverent, 
almost by definition. What matters is phase noise and short-term stability, 
neither of which you can possibly fix with disciplining against GPS. GPS takes 
care of the rest.

Long-term stability can be critical for non-GPS applications, which is why 
oscillators with daily aging rates in the -11's and -12's are so amazing.

Consider this: if you want to run your bench with a clean 10 MHz source, stable 
to 11 or 12 digits and accurate to 9 digits -- you may be much better off with 
a free-running, stand-alone OCXO with an aging rate down at 1e-11/day than 
using a GPSDO/TCXO. To maintain accuracy of your OCXO just re-tune your OCXO 
*once a year*. Aside from ADEV plots, this is another way to appreciate how 
amazing some OCXO are, any why many of us still troll eBay for high-stability, 
low-noise, low-drift quartz oscillators.

/tvb

- Original Message - 
From: Bert Kehren via time-nuts time-nuts@febo.com
To: time-nuts@febo.com
Sent: Monday, October 20, 2014 4:01 PM
Subject: Re: [time-nuts] LTE-Lite module


Allow me to clarify.
I started out with 7 MV 89 one of it a total loss. The remaining 6 after 3  
month +  burn in show better than 1 E-11 aging per day, 2 closer to 5 E-12. 
 Only two have been tested for ADEV and are close to 1 E-12,  2X not 10  X.
Bert Kehren
 

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Charles Steinmetz




here is the ADEV plot from my overnight test with the DOCXO.  *  *  *

This was done without any loop adjustment whatsoever, same board and
software that drives the on-board TCXO. I will let the result speak 
for  itself,

save to say the loop, the DAC, the DAC reference, and the GPS with a  proper
OCXO can achieve performance at a level approaching two orders of
magnitude better than our spec which is 1ppb for this  particular product.


Thanks for the ADEV plot, Said -- more pertinent for most time nuts 
purposes than PN.  Of course, the typical performance of the LTE-Lite 
with the TCXO is significantly better than the spec (according to the 
user manual, about 5e-11 at 1 second and 1e-10 at 10 seconds, already 
1 to 1.5 OOM better than spec), so the typical improvement with the 
OCXO wouldn't be a full two orders of magnitude.  Still, very 
noteworthy performance that *surely* justifies time nuts in buying 
one of the good, cheap OCXOs flooding the surplus market to go along 
with their LTE-Lite.  Good show.


Best regards,

Charles



___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Bob Stewart

Hi Tom,

One of the biggest problems I've unwittingly faces is that of retrace.  I had 
seen the term used several times, but hadn't looked it up until last night.  As 
you can imagine, with a GPSDO under development I've had to remove power more 
than a few times to make hardware changes.  I think the next time power is down 
I'm going to try to rearrange things so that the OCXO is permanently powered 
and just the board gets switched.  But then again would big jumps in the EFC 
cause other problems that are almost as bad?  


There is just so much to learn to get this going; especially without either an 
engineering degree or experience in this field.  Bob Camp is definitely right 
that you have to put your time in - lots of it.


Bob - AE6RV



 From: Tom Van Baak t...@leapsecond.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Monday, October 20, 2014 6:42 PM
Subject: Re: [time-nuts] LTE-Lite module
 

To add to Bert's note...

Realize that for a GPSDO, (linear frequency) aging-per-day is irreverent, 
almost by definition. What matters is phase noise and short-term stability, 
neither of which you can possibly fix with disciplining against GPS. GPS takes 
care of the rest.

Long-term stability can be critical for non-GPS applications, which is why 
oscillators with daily aging rates in the -11's and -12's are so amazing.

Consider this: if you want to run your bench with a clean 10 MHz source, stable 
to 11 or 12 digits and accurate to 9 digits -- you may be much better off with 
a free-running, stand-alone OCXO with an aging rate down at 1e-11/day than 
using a GPSDO/TCXO. To maintain accuracy of your OCXO just re-tune your OCXO 
*once a year*. Aside from ADEV plots, this is another way to appreciate how 
amazing some OCXO are, any why many of us still troll eBay for high-stability, 
low-noise, low-drift quartz oscillators.

/tvb

- Original Message - 
From: Bert Kehren via time-nuts time-nuts@febo.com
To: time-nuts@febo.com
Sent: Monday, October 20, 2014 4:01 PM
Subject: Re: [time-nuts] LTE-Lite module


Allow me to clarify.
I started out with 7 MV 89 one of it a total loss. The remaining 6 after 3  
month +  burn in show better than 1 E-11 aging per day, 2 closer to 5 E-12. 
Only two have been tested for ADEV and are close to 1 E-12,  2X not 10  X.
Bert Kehren


___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Bob Stewart

OK, Yahoo has done it to me again.  Sent to Tom direct and not to the list.  
So, repeated here:

Hi Tom,

One of the biggest problems I've unwittingly faces is that of retrace.  I 
had seen the term used several times, but hadn't looked it up until last night. 
 As you can imagine, with a GPSDO under development I've had to 
remove power more than a few times to make hardware changes.  I think 
the next time power is down I'm going to try to rearrange things so that the 
OCXO is permanently powered and just the board gets switched.  But 
then again would big jumps in the EFC cause other problems that are 
almost as bad?  


There is just so much to learn to get this going; especially without either 
an engineering degree or experience in this field.  Bob Camp is 
definitely right that you have to put your time in - lots of it.

Bob - AE6RV



 From: Tom Van Baak t...@leapsecond.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com 
Sent: Monday, October 20, 2014 6:42 PM
Subject: Re: [time-nuts] LTE-Lite module
 

To add to Bert's note...

Realize that for a GPSDO, (linear frequency) aging-per-day is irreverent, 
almost by definition. What matters is phase noise and short-term stability, 
neither of which you can possibly fix with disciplining against GPS. GPS takes 
care of the rest.

Long-term stability can be critical for non-GPS applications, which is why 
oscillators with daily aging rates in the -11's and -12's are so amazing.

Consider this: if you want to run your bench with a clean 10 MHz source, stable 
to 11 or 12 digits and accurate to 9 digits -- you may be much better off with 
a free-running, stand-alone OCXO with an aging rate down at 1e-11/day than 
using a GPSDO/TCXO. To maintain accuracy of your OCXO just re-tune your OCXO 
*once a year*. Aside from ADEV plots, this is another way to appreciate how 
amazing some OCXO are, any why many of us still troll eBay for high-stability, 
low-noise, low-drift quartz oscillators.

/tvb

- Original Message - 
From: Bert Kehren via time-nuts time-nuts@febo.com
To: time-nuts@febo.com
Sent: Monday, October 20, 2014 4:01 PM
Subject: Re: [time-nuts] LTE-Lite module


Allow me to clarify.
I started out with 7 MV 89 one of it a total loss. The remaining 6 after 3  
month +  burn in show better than 1 E-11 aging per day, 2 closer to 5 E-12. 
Only two have been tested for ADEV and are close to 1 E-12,  2X not 10  X.
Bert Kehren


___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Said Jackson via time-nuts

Bob,

You are on the right track!

Large changes in EFC can cause hysteresis, meaning you go back to an initial 
voltage but the crystal does not return to the exact initial frequency. It can 
also create dead bands in the efc vs frequency curve.

Hysteresis can cause integrator wind up as the loop is chasing an ever changing 
OCXO..

Retrace and hysteresis are two major issues for any disciplined oscillator.

Bye,
Said

Sent From iPhone

 On Oct 20, 2014, at 17:03, Bob Stewart b...@evoria.net wrote:
 
 OK, Yahoo has done it to me again.  Sent to Tom direct and not to the list.  
 So, repeated here:
 
 Hi Tom,
 
 One of the biggest problems I've unwittingly faces is that of retrace.  I 
 had seen the term used several times, but hadn't looked it up until last 
 night.  As you can imagine, with a GPSDO under development I've had to 
 remove power more than a few times to make hardware changes.  I think 
 the next time power is down I'm going to try to rearrange things so that the 
 OCXO is permanently powered and just the board gets switched.  But 
 then again would big jumps in the EFC cause other problems that are 
 almost as bad?  
 
 
 There is just so much to learn to get this going; especially without either 
 an engineering degree or experience in this field.  Bob Camp is 
 definitely right that you have to put your time in - lots of it.
 
 Bob - AE6RV
 
 
 
 From: Tom Van Baak t...@leapsecond.com
 To: Discussion of precise time and frequency measurement time-nuts@febo.com 
 Sent: Monday, October 20, 2014 6:42 PM
 Subject: Re: [time-nuts] LTE-Lite module
 
 
 To add to Bert's note...
 
 Realize that for a GPSDO, (linear frequency) aging-per-day is irreverent, 
 almost by definition. What matters is phase noise and short-term stability, 
 neither of which you can possibly fix with disciplining against GPS. GPS 
 takes care of the rest.
 
 Long-term stability can be critical for non-GPS applications, which is why 
 oscillators with daily aging rates in the -11's and -12's are so amazing.
 
 Consider this: if you want to run your bench with a clean 10 MHz source, 
 stable to 11 or 12 digits and accurate to 9 digits -- you may be much better 
 off with a free-running, stand-alone OCXO with an aging rate down at 
 1e-11/day than using a GPSDO/TCXO. To maintain accuracy of your OCXO just 
 re-tune your OCXO *once a year*. Aside from ADEV plots, this is another way 
 to appreciate how amazing some OCXO are, any why many of us still troll eBay 
 for high-stability, low-noise, low-drift quartz oscillators.
 
 /tvb
 
 - Original Message - 
 From: Bert Kehren via time-nuts time-nuts@febo.com
 To: time-nuts@febo.com
 Sent: Monday, October 20, 2014 4:01 PM
 Subject: Re: [time-nuts] LTE-Lite module
 
 
 Allow me to clarify.
 I started out with 7 MV 89 one of it a total loss. The remaining 6 after 3  
 month +  burn in show better than 1 E-11 aging per day, 2 closer to 5 E-12. 
 Only two have been tested for ADEV and are close to 1 E-12,  2X not 10  X.
 Bert Kehren
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Bob Stewart

Hi Said,

OK, I hadn't understood the full consequences of hysteresis, but yes, I've seen 
it.  For an hour the DAC ratchets up a step every few minutes and the phase 
stubbornly stays put.  And then, the bottom falls out and it suddenly pushes 
way past where you want it.  Well, at least I have a better understanding of it 
now.  I'll try to avoid any hardware changes for the next few weeks.  I may 
even make changes that will keep the DAC stable when loading new code.

Thanks!


Bob




 From: Said Jackson saidj...@aol.com
To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency 
measurement time-nuts@febo.com 
Sent: Monday, October 20, 2014 7:21 PM
Subject: Re: [time-nuts] LTE-Lite module
 

Bob,

You are on the right track!

Large changes in EFC can cause hysteresis, meaning you go back to an initial 
voltage but the crystal does not return to the exact initial frequency. It can 
also create dead bands in the efc vs frequency curve.

Hysteresis can cause integrator wind up as the loop is chasing an ever changing 
OCXO..

Retrace and hysteresis are two major issues for any disciplined oscillator.

Bye,
Said

Sent From iPhone




 On Oct 20, 2014, at 17:03, Bob Stewart b...@evoria.net wrote:
 
 OK, Yahoo has done it to me again.  Sent to Tom direct and not to the list.  
 So, repeated here:
 
 Hi Tom,
 
 One of the biggest problems I've unwittingly faces is that of retrace.  I 
 had seen the term used several times, but hadn't looked it up until last 
 night.  As you can imagine, with a GPSDO under development I've had to 
 remove power more than a few times to make hardware changes.  I think 
 the next time power is down I'm going to try to rearrange things so that the 
 OCXO is permanently powered and just the board gets switched.  But 
 then again would big jumps in the EFC cause other problems that are 
 almost as bad?  
 
 
 There is just so much to learn to get this going; especially without either 
 an engineering degree or experience in this field.  Bob Camp is 
 definitely right that you have to put your time in - lots of it.
 
 Bob - AE6RV
 
 
 
 From: Tom Van Baak t...@leapsecond.com
 To: Discussion of precise time and frequency measurement time-nuts@febo.com 
 Sent: Monday, October 20, 2014 6:42 PM
 Subject: Re: [time-nuts] LTE-Lite module
 
 
 To add to Bert's note...
 
 Realize that for a GPSDO, (linear frequency) aging-per-day is irreverent, 
 almost by definition. What matters is phase noise and short-term stability, 
 neither of which you can possibly fix with disciplining against GPS. GPS 
 takes care of the rest.
 
 Long-term stability can be critical for non-GPS applications, which is why 
 oscillators with daily aging rates in the -11's and -12's are so amazing.
 
 Consider this: if you want to run your bench with a clean 10 MHz source, 
 stable to 11 or 12 digits and accurate to 9 digits -- you may be much better 
 off with a free-running, stand-alone OCXO with an aging rate down at 
 1e-11/day than using a GPSDO/TCXO. To maintain accuracy of your OCXO just 
 re-tune your OCXO *once a year*. Aside from ADEV plots, this is another way 
 to appreciate how amazing some OCXO are, any why many of us still troll eBay 
 for high-stability, low-noise, low-drift quartz oscillators.
 
 /tvb
 
 - Original Message - 
 From: Bert Kehren via time-nuts time-nuts@febo.com
 To: time-nuts@febo.com
 Sent: Monday, October 20, 2014 4:01 PM
 Subject: Re: [time-nuts] LTE-Lite module
 
 
 Allow me to clarify.
 I started out with 7 MV 89 one of it a total loss. The remaining 6 after 3  
 month +  burn in show better than 1 E-11 aging per day, 2 closer to 5 E-12. 
 Only two have been tested for ADEV and are close to 1 E-12,  2X not 10  X.
 Bert Kehren
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-20 Thread Said Jackson via time-nuts

Thats exactly right Bob.

By the time your ocxo jumps to catch up to the efc voltage, you have 
oversteered,  then the process starts in reverse and the ocxo jumps in the 
opposite direction.

The result is a phase jumping up and down.

You want a crystal that reacts to xE-012 changes in EFC voltage or even 
better.. We may be talking only 100s of nanovolts per LSB.

Bye,
Said

Sent From iPhone

 On Oct 20, 2014, at 17:30, Bob Stewart b...@evoria.net wrote:
 
 Hi Said,
 
 OK, I hadn't understood the full consequences of hysteresis, but yes, I've 
 seen it.  For an hour the DAC ratchets up a step every few minutes and the 
 phase stubbornly stays put.  And then, the bottom falls out and it suddenly 
 pushes way past where you want it.  Well, at least I have a better 
 understanding of it now.  I'll try to avoid any hardware changes for the next 
 few weeks.  I may even make changes that will keep the DAC stable when 
 loading new code.
 
 Thanks!
 
 Bob
 
 From: Said Jackson saidj...@aol.com
 To: Bob Stewart b...@evoria.net; Discussion of precise time and frequency 
 measurement time-nuts@febo.com 
 Sent: Monday, October 20, 2014 7:21 PM
 Subject: Re: [time-nuts] LTE-Lite module
 
 Bob,
 
 You are on the right track!
 
 Large changes in EFC can cause hysteresis, meaning you go back to an initial 
 voltage but the crystal does not return to the exact initial frequency. It 
 can also create dead bands in the efc vs frequency curve.
 
 Hysteresis can cause integrator wind up as the loop is chasing an ever 
 changing OCXO..
 
 Retrace and hysteresis are two major issues for any disciplined oscillator.
 
 Bye,
 Said
 
 Sent From iPhone
 
 
 
  On Oct 20, 2014, at 17:03, Bob Stewart b...@evoria.net wrote:
  
  OK, Yahoo has done it to me again.  Sent to Tom direct and not to the list. 
   So, repeated here:
  
  Hi Tom,
  
  One of the biggest problems I've unwittingly faces is that of retrace.  I 
  had seen the term used several times, but hadn't looked it up until last 
  night.  As you can imagine, with a GPSDO under development I've had to 
  remove power more than a few times to make hardware changes.  I think 
  the next time power is down I'm going to try to rearrange things so that 
  the OCXO is permanently powered and just the board gets switched.  But 
  then again would big jumps in the EFC cause other problems that are 
  almost as bad?  
  
  
  There is just so much to learn to get this going; especially without either 
  an engineering degree or experience in this field.  Bob Camp is 
  definitely right that you have to put your time in - lots of it.
  
  Bob - AE6RV
  
  
  
  From: Tom Van Baak t...@leapsecond.com
  To: Discussion of precise time and frequency measurement 
  time-nuts@febo.com 
  Sent: Monday, October 20, 2014 6:42 PM
  Subject: Re: [time-nuts] LTE-Lite module
  
  
  To add to Bert's note...
  
  Realize that for a GPSDO, (linear frequency) aging-per-day is irreverent, 
  almost by definition. What matters is phase noise and short-term stability, 
  neither of which you can possibly fix with disciplining against GPS. GPS 
  takes care of the rest.
  
  Long-term stability can be critical for non-GPS applications, which is why 
  oscillators with daily aging rates in the -11's and -12's are so amazing.
  
  Consider this: if you want to run your bench with a clean 10 MHz source, 
  stable to 11 or 12 digits and accurate to 9 digits -- you may be much 
  better off with a free-running, stand-alone OCXO with an aging rate down at 
  1e-11/day than using a GPSDO/TCXO. To maintain accuracy of your OCXO just 
  re-tune your OCXO *once a year*. Aside from ADEV plots, this is another way 
  to appreciate how amazing some OCXO are, any why many of us still troll 
  eBay for high-stability, low-noise, low-drift quartz oscillators.
  
  /tvb
  
  - Original Message - 
  From: Bert Kehren via time-nuts time-nuts@febo.com
  To: time-nuts@febo.com
  Sent: Monday, October 20, 2014 4:01 PM
  Subject: Re: [time-nuts] LTE-Lite module
  
  
  Allow me to clarify.
  I started out with 7 MV 89 one of it a total loss. The remaining 6 after 3  
  month +  burn in show better than 1 E-11 aging per day, 2 closer to 5 E-12. 
  Only two have been tested for ADEV and are close to 1 E-12,  2X not 10  X.
  Bert Kehren
  
  
  ___
  time-nuts mailing list -- time-nuts@febo.com
  To unsubscribe, go to 
  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
  and follow the instructions there.
  ___
  time-nuts mailing list -- time-nuts@febo.com
  To unsubscribe, go to 
  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
  and follow the instructions there.
 
 
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-19 Thread Bill Riches

Hi Said,

Thank you for taking the time to answer questions and provide info on the LTE 
unit to our group.  I know we will not add much to your bottom line as we are a 
small group.  We have come a long way with Thunderbolt without any help 
whatsoever with that company.  Will be an interesting ride with your products!

73,

Bill, WA2DVU
Cape May, NJ

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Said Jackson 
via time-nuts
Sent: Saturday, October 18, 2014 6:53 PM
To: Bill Dailey
Cc: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] LTE-Lite module

Hi Bill,

I think it makes perfect sense. But I have no idea how the units' loop 
stability would be with the 10811. That kind of testing is on the plate.

You would preferably set the OCXO to a nominal tuning voltage of 1.5V using the 
mechanical adjustment, then let the LTE Lite do the rest.

Please note that the LTE board will auto-sense the external ocxo frequency, so 
any of the boards would work.

Please also note that due to the harmonic mixing issues I described earlier the 
best board to use for that setup would be the 19.2MHz version(!) or to remove 
the on-board tcxo altogether.

Bye,
Said

Sent From iPhone

 On Oct 18, 2014, at 15:24, Bill Dailey docdai...@gmail.com wrote:
 
 Said,
 
 How tough would it be to mate the 10Mhz version up to a really good 10811?  I 
 have one that I acquired from Corby some time ago.  I was going to spin my 
 own but I wont realistically get to that with everything else I have going 
 on.  I was thinking of throwing the LTE-Lite and  the 10811 in a box.  I 
 woudl then have a stock fury, An enhanced OEM fury (datum-c) and then 
 this gadget with a 10-13 10811.  Let me know if this doesnt make sense.  I am 
 an amateur.
 
 Bill
 
 On Sat, Oct 18, 2014 at 5:13 PM, S. Jackson via time-nuts 
 time-nuts@febo.com wrote:
 Guys,
 
 one last email. The board will not fit into the Hammond enclosure 
 without reworking the enclosure or removing the TCXO socket. We 
 initially planned to  ship the board without the socket, now all of 
 them will have it. The board was designed to be used without the 
 TCXO/Socket to fit into that enclosure.
 
 Caveat: please expect some rework to be necessary when using the  
 suggested Hammond enclosure.
 
 bye,
 Said
 
 
 In a message dated 10/18/2014 12:56:06 Pacific Daylight Time, 
 time-nuts@febo.com writes:
 
 
 Guys,
 we have been getting a good number of emails with  questions  that 
 have already been addressed in the user manual or the  FAQ, see the  below 
 link.
 We
 spent a lot of time putting the  collateral together, may I please  
 ask that you first look into these  two documents to see if your 
 question might already be addressed  there?
 Paul,
 please search the LTE Lite user manual for Hammond and  you will  
 find it
 there:
 http://www.jackson-labs.com/index.php/products/lte_lite
 Thanks,
 Said
 _
 Do you have a recommended  Hammond chassis part  number?
 --
 Paul
 ___
 time-nuts  mailing list -- time-nuts@febo.com To unsubscribe, go to 
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the  instructions there.
 
 ___
 time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
 
 
 
 --
 Doc
 
 Bill Dailey
 KXØO
  
 
 

___
time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.


---
This email is free from viruses and malware because avast! Antivirus protection 
is active.
http://www.avast.com

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-19 Thread Charles Steinmetz


Bill wrote:


How tough would it be to mate the 10Mhz version up to a really good 10811?
*   *   *   I was thinking of throwing the LTE-Lite and the 10811 in a box.


Unfortunately, to get the best out of the local oscillator, the 
control PLL must be carefully adjusted so that the oscillator itself 
controls the stability at averaging times (tau) where it is better 
than the GPS (generally, up to tau of several hundred to maybe 
several thousand seconds), and the GPS controls the stability at 
longer tau.  The LTE-Lite has fixed (non-adjustable) loop parameters 
that cross over to the GPS at much lower tau than is appropriate for 
a good OCXO (but well suited to the installed TXCO).


The other day Said (I think) mentioned some hacks that may sort-of 
improve the ability of an LTE-Lite to discipline an OCXO, but that's 
all they are -- very approximate hacks.  There is really no way to 
properly mate an OCXO to the LTE-Lite control loop, which would 
require adjusting the PLL loop gain and the location of the loop's 
poles and zeroes (and possibly even adding new poles and 
zeroes).  That would need to be done by changing the PLL parameters 
internal to the LTE-Lite, which are inaccessible.  Without such 
reprogramming, the LTE-Light can never get the best out of an OCXO.


Best regards,

Charles



___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-19 Thread Poul-Henning Kamp


In message 20141019155055.osmik...@smtp11.mail.yandex.net, Charles Steinmetz 
writes:

zeroes).  That would need to be done by changing the PLL parameters 
internal to the LTE-Lite, which are inaccessible.  Without such 
reprogramming, the LTE-Light can never get the best out of an OCXO.

It certainly can and it's not even hard:

Configure the LTE to emit a suitable frequency relative to the
OCXO and use an analog PLL to steer the OCXO's EFC.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-19 Thread Charles Steinmetz


Poul-Henning wrote:


zeroes).  That would need to be done by changing the PLL parameters
internal to the LTE-Lite, which are inaccessible.  Without such
reprogramming, the LTE-Light can never get the best out of an OCXO.

It certainly can and it's not even hard:

Configure the LTE to emit a suitable frequency relative to the
OCXO and use an analog PLL to steer the OCXO's EFC.


Any worthwhile OCXO will need a loop with a time constant on the 
order of hundreds of seconds (a corner frequency on the order of uHz) 
to get the most out of it as a GPSDO.  As has been discussed on the 
list many times, there is simply no practicable way to design an 
analog loop with such a long time constant.  So the person designing 
the PLL must be able to design and build an all-digital PLL, or 
settle for a loop that crosses over to the GPS several decades too 
early (which is certainly not getting the most out of the OCXO).


Best regards,

Charles



___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-19 Thread Poul-Henning Kamp


In message 20141019183956.dt4ss...@smtp2o.mail.yandex.net, Charles Steinmetz 
writes:

Configure the LTE to emit a suitable frequency relative to the
OCXO and use an analog PLL to steer the OCXO's EFC.


Then do it digital, it's not like it's rocket science...

Take the analog phase detector output, read it with ADC pin,
do loop in software, drive efc with DAC.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Hi

The phase comparison part of the PLL is pretty straightforward if you are 
looking at two RF frequencies. An XOR gate is one solution, there are many 
others. Getting something like 100 to 200 ns full scale on the phase comparator 
makes the rest of the gizmo much easier. A 12 bit ADC on a MCU will get you to 
100’s of ps per bit., That is more resolution (it’s  1 ns) than you need for 
this. Controlling the OCXO is either an outboard ADC ($2 or so) or a PWM (free 
with the MCU).  There will be a few regulators, resistors, caps, and maybe a 
pot or two involved as well. 

Total parts cost on the digital loop done with an appropriate MCU is probably 
less than $10. Custom code wise, it’s a few hundred lines of C on a 32 bit ARM. 
Pre built (wizard driven) device init stuff will be way more than that, but you 
don’t write any of that. Since it’s just a PLL and not a full GPSDO, there’s 
not a whole lot to it. If building up the MCU board is the issue, there are 
*many* eval boards out there for  $15 that will do the trick. 

Debug, optimization and tweaking are where the major effort is (like 80 to 
90%). That will take at least few months of work and require some test gear. 
Any time you plug in a significantly different oscillator, you will have to put 
in this part of the effort. Getting the long run ADEV data, making sure it’s 
right, and then analyzing the result is something there is no magic shortcut 
around. If you are set up for it (you are a TIme Nut right?) , there’s no cost 
other than your time. If it’s a hobby - your time is free (or is it …). 

No it’s not a “plug in a pre-made gizmo and forget about it” sort of thing. 
There is real work, lots of  time, mental effort, working gear, and patience 
involved. You *will* get it wrong more often than you get it right as you go 
through the process. Stuff happens, runs crash, gear fails, it’s the real 
world. That’s the learning part of the project. If its a hobby that’s what you 
are doing this for. 

Bob

 On Oct 19, 2014, at 10:39 AM, Charles Steinmetz csteinm...@yandex.com wrote:
 
 Poul-Henning wrote:
 
 zeroes).  That would need to be done by changing the PLL parameters
 internal to the LTE-Lite, which are inaccessible.  Without such
 reprogramming, the LTE-Light can never get the best out of an OCXO.
 
 It certainly can and it's not even hard:
 
 Configure the LTE to emit a suitable frequency relative to the
 OCXO and use an analog PLL to steer the OCXO's EFC.
 
 Any worthwhile OCXO will need a loop with a time constant on the order of 
 hundreds of seconds (a corner frequency on the order of uHz) to get the most 
 out of it as a GPSDO.  As has been discussed on the list many times, there is 
 simply no practicable way to design an analog loop with such a long time 
 constant.  So the person designing the PLL must be able to design and build 
 an all-digital PLL, or settle for a loop that crosses over to the GPS several 
 decades too early (which is certainly not getting the most out of the OCXO).
 
 Best regards,
 
 Charles
 
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Hi

 On Oct 19, 2014, at 3:35 PM, Charles Steinmetz csteinm...@yandex.com wrote:
 
 Bob wrote (alluding also to something Poul-Henning wrote):
 
 The phase comparison part of the PLL is pretty straightforward if you are 
 looking at two RF frequencies. An XOR gate is one solution, there are many 
 others. Getting something like 100 to 200 ns full scale on the phase 
 comparator makes the rest of the gizmo much easier.
 
 All true.  However...
 
 A 12 bit ADC on a MCU will get you to 100's of ps per bit.  That is more 
 resolution (it's  1 ns) than you need for this.
 
 Getting an ADC to sample fast and accurately enough to provide that honest 
 resolution is not trivial.  And if you have that, you'll almost certainly 
 have the resources to do the phase comparator digitally, too, which brings 
 many advantages -- so I see no reason to use an analog PC.

If you take a look at some of the newer ARM MCU’s they are getting 13+ solid 
bits out of their ADC’s at a  10 KHz rate. That’s more than good enough for 
anything you are trying to do with this design. There’s no need to make it any 
more complex. 

A single gate XOR plus the eval board is just a about all you need. One dead 
bug part on the eval board and the assembly process is pretty much done. Maybe 
45 minutes of work if you need to go find all the bits and pieces around your 
bench.  Since almost nothing in the design is running at high speed, layout 
issues should not be a big deal. You could also do it on a fragment of board 
like the divider from earlier in this thread. 

 
 Custom code wise, it's a few hundred lines of C on a 32 bit ARM. Pre built 
 (wizard driven) device init stuff will be way more than that, but you don't 
 write any of that.
 
 A proper digital filter that computes a new running value at least every 
 second will be more complex than that, but you're right, it's not an 
 unfathomable task.
 
 Then comes the real work, well summarized by Bob:
 
 Debug, optimization and tweaking are where the major effort is (like 80 to 
 90%). That will take at least few months of work and require some test gear. 
 Any time you plug in a significantly different oscillator, you will have to 
 put in this part of the effort. Getting the long run ADEV data, making sure 
 it's right, and then analyzing the result is something there is no magic 
 shortcut around.   *  *  *
 
 No it's not a plug in a pre-made gizmo and forget about it sort of thing. 
 There is real work, lots of  time, mental effort, working gear, and patience 
 involved. You *will* get it wrong more often than you get it right as you go 
 through the process.
 
 All of this explains why the woods are not full of state-of-the-art GPSDO 
 controllers just waiting for people to couple them with whatever OCXO they 
 bought on ebay.

The optimization process is at least 90% perspiration and preparation. Neither 
of those are outside the range of what an average Joe can handle. The other (at 
most) 10% is very much a “that depends” sort of thing. You can head down all 
sorts of rabbit holes as you dig into this or that. For that, the list archives 
have tons of information to work from. 

There is *way* more in a GPSDO than what we are talking about here. TimeNuts 
may or may not care much about that extra stuff, but it’s in there. 

 
 BTW, I mean no slight to the LTE-Light.  Judging from the JL products I've 
 used, I expect that it is a fine product well-designed for its task.  But 
 that task is controlling a TCXO, not controlling an OCXO that is stable to 
 10e-12 or better at tau from 1 to 100 seconds (unless one goes to the trouble 
 described above).
 
 For a general look at the magnitude of the stability difference between a 
 TCXO and a number of OCXOs and other frequency standards, see attached (if 
 the pic doesn't make it through the listserv, see 
 http://leapsecond.com/museum/manyadev.gif).
 
 Best regards,
 
 Charles
 
 
 Oscillator_comparison_tvb.jpg___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

The idea is not to make it as complex as you possibly could, but to make it as 
simple as possible and still have it work fine. There are a lot of shortcuts 
you can take with a one off unit that a commercial design would never use.

Bob

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-19 Thread Bert Kehren via time-nuts

With all the work around if you want very good performance use  a Shera. We 
have super results with a Morion, Shera and ublox M7
Bert Kehren
 
 
In a message dated 10/19/2014 4:08:32 P.M. Eastern Daylight Time,  
kb...@n1k.org writes:

Hi

 On Oct 19, 2014, at 3:35 PM, Charles Steinmetz  csteinm...@yandex.com 
wrote:
 
 Bob wrote (alluding also  to something Poul-Henning wrote):
 
 The phase comparison  part of the PLL is pretty straightforward if you 
are looking at two RF  frequencies. An XOR gate is one solution, there are 
many others. Getting  something like 100 to 200 ns full scale on the phase 
comparator makes the rest  of the gizmo much easier.
 
 All true.  However...
  
 A 12 bit ADC on a MCU will get you to 100's of ps per bit.   That is 
more resolution (it's  1 ns) than you need for this.
  
 Getting an ADC to sample fast and accurately enough to provide that  
honest resolution is not trivial.  And if you have that, you'll almost  
certainly have the resources to do the phase comparator digitally, too, which  
brings many advantages -- so I see no reason to use an analog PC.

If  you take a look at some of the newer ARM MCU’s they are getting 13+ 
solid bits  out of their ADC’s at a  10 KHz rate. That’s more than good 
enough for  anything you are trying to do with this design. There’s no need to 
make it any  more complex. 

A single gate XOR plus the eval board is just a about  all you need. One 
dead bug part on the eval board and the assembly process is  pretty much done. 
Maybe 45 minutes of work if you need to go find all the bits  and pieces 
around your bench.  Since almost nothing in the design is  running at high 
speed, layout issues should not be a big deal. You could also  do it on a 
fragment of board like the divider from earlier in this thread.  

 
 Custom code wise, it's a few hundred lines of C on a  32 bit ARM. Pre 
built (wizard driven) device init stuff will be way more than  that, but you 
don't write any of that.
 
 A proper digital  filter that computes a new running value at least every 
second will be more  complex than that, but you're right, it's not an 
unfathomable task.
  
 Then comes the real work, well summarized by Bob:
  
 Debug, optimization and tweaking are where the major effort is  (like 80 
to 90%). That will take at least few months of work and require some  test 
gear. Any time you plug in a significantly different oscillator, you will  
have to put in this part of the effort. Getting the long run ADEV data, 
making  sure it's right, and then analyzing the result is something there is no 
magic  shortcut around.   *  *  *
 
 No  it's not a plug in a pre-made gizmo and forget about it sort of 
thing.  There is real work, lots of  time, mental effort, working gear, and  
patience involved. You *will* get it wrong more often than you get it right 
as  you go through the process.
 
 All of this explains why the  woods are not full of state-of-the-art 
GPSDO controllers just waiting for  people to couple them with whatever OCXO 
they bought on ebay.

The  optimization process is at least 90% perspiration and preparation. 
Neither of  those are outside the range of what an average Joe can handle. The 
other (at  most) 10% is very much a “that depends” sort of thing. You can 
head down all  sorts of rabbit holes as you dig into this or that. For that, 
the list  archives have tons of information to work from. 

There is *way* more in  a GPSDO than what we are talking about here. 
TimeNuts may or may not care much  about that extra stuff, but it’s in there. 

 
 BTW, I mean  no slight to the LTE-Light.  Judging from the JL products 
I've used, I  expect that it is a fine product well-designed for its task.  
But that  task is controlling a TCXO, not controlling an OCXO that is stable 
to 10e-12  or better at tau from 1 to 100 seconds (unless one goes to the 
trouble  described above).
 
 For a general look at the magnitude of the  stability difference between 
a TCXO and a number of OCXOs and other frequency  standards, see attached 
(if the pic doesn't make it through the listserv, see  
http://leapsecond.com/museum/manyadev.gif).
 
 Best  regards,
 
 Charles
 
 
  
Oscillator_comparison_tvb.jpg___
  time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the  instructions there.

The idea is not to make it as complex as you  possibly could, but to make 
it as simple as possible and still have it work  fine. There are a lot of 
shortcuts you can take with a one off unit that a  commercial design would 
never  use.

Bob

___
time-nuts  mailing list -- time-nuts@febo.com
To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the  instructions there.
___
time-nuts mailing list -- time-nuts@febo.com
To

Re: [time-nuts] LTE-Lite module

2014-10-19 Thread Charles Steinmetz


Bob wrote (alluding also to something Poul-Henning wrote):

The phase comparison part of the PLL is pretty 
straightforward if you are looking at two RF 
frequencies. An XOR gate is one solution, there 
are many others. Getting something like 100 to 
200 ns full scale on the phase comparator makes 
the rest of the gizmo much easier.


All true.  However...

A 12 bit ADC on a MCU will get you to 100's of 
ps per bit.  That is more resolution (it's  1 ns) than you need for this.


Getting an ADC to sample fast and accurately 
enough to provide that honest resolution is not 
trivial.  And if you have that, you'll almost 
certainly have the resources to do the phase 
comparator digitally, too, which brings many 
advantages -- so I see no reason to use an analog PC.


Custom code wise, it's a few hundred lines of C 
on a 32 bit ARM. Pre built (wizard driven) 
device init stuff will be way more than that, but you don't write any of that.


A proper digital filter that computes a new 
running value at least every second will be more 
complex than that, but you're right, it's not an unfathomable task.


Then comes the real work, well summarized by Bob:

Debug, optimization and tweaking are where the 
major effort is (like 80 to 90%). That will take 
at least few months of work and require some 
test gear. Any time you plug in a significantly 
different oscillator, you will have to put in 
this part of the effort. Getting the long run 
ADEV data, making sure it's right, and then 
analyzing the result is something there is no magic shortcut around.   *  *  *


No it's not a plug in a pre-made gizmo and 
forget about it sort of thing. There is real 
work, lots of  time, mental effort, working 
gear, and patience involved. You *will* get it 
wrong more often than you get it right as you go through the process.


All of this explains why the woods are not full 
of state-of-the-art GPSDO controllers just 
waiting for people to couple them with whatever OCXO they bought on ebay.


BTW, I mean no slight to the LTE-Light.  Judging 
from the JL products I've used, I expect that it 
is a fine product well-designed for its 
task.  But that task is controlling a TCXO, not 
controlling an OCXO that is stable to 10e-12 or 
better at tau from 1 to 100 seconds (unless one 
goes to the trouble described above).


For a general look at the magnitude of the 
stability difference between a TCXO and a number 
of OCXOs and other frequency standards, see 
attached (if the pic doesn't make it through the 
listserv, see http://leapsecond.com/museum/manyadev.gif).


Best regards,

Charles


___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-19 Thread Jim Lux


On 10/19/14, 1:08 PM, Bob Camp wrote:

Hi


On Oct 19, 2014, at 3:35 PM, Charles Steinmetz
csteinm...@yandex.com wrote:

Bob wrote (alluding also to something Poul-Henning wrote):


The phase comparison part of the PLL is pretty straightforward if
you are looking at two RF frequencies. An XOR gate is one
solution, there are many others. Getting something like 100 to
200 ns full scale on the phase comparator makes the rest of the
gizmo much easier.


All true.  However...


A 12 bit ADC on a MCU will get you to 100's of ps per bit.  That
is more resolution (it's  1 ns) than you need for this.


Getting an ADC to sample fast and accurately enough to provide that
honest resolution is not trivial.  And if you have that, you'll
almost certainly have the resources to do the phase comparator
digitally, too, which brings many advantages -- so I see no reason
to use an analog PC.


If you take a look at some of the newer ARM MCU’s they are getting
13+ solid bits out of their ADC’s at a  10 KHz rate. That’s more
than good enough for anything you are trying to do with this design.
There’s no need to make it any more complex.


I'm using the Freescale Kinetix K20 parts, which have 16 bit 
differential input ADCs, and built in averaging.  The raw ADC can sample 
at about 400kHz.


You can easily get 14 bit performance from these at tens of kHz rates.
I need I/Q, so I sample two inputs at 50 kHz (read one, then the other) 
without averaging (so they're about 2.5 microseconds apart), and then 
decimate them through a 2 stage CIC and a 13 tap FIR filter down to 200 
Hz.  This takes about 60% of the processor running at 48MHz.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Hi

 On Oct 19, 2014, at 5:00 PM, Jim Lux jim...@earthlink.net wrote:
 
 On 10/19/14, 1:08 PM, Bob Camp wrote:
 Hi
 
 On Oct 19, 2014, at 3:35 PM, Charles Steinmetz
 csteinm...@yandex.com wrote:
 
 Bob wrote (alluding also to something Poul-Henning wrote):
 
 The phase comparison part of the PLL is pretty straightforward if
 you are looking at two RF frequencies. An XOR gate is one
 solution, there are many others. Getting something like 100 to
 200 ns full scale on the phase comparator makes the rest of the
 gizmo much easier.
 
 All true.  However...
 
 A 12 bit ADC on a MCU will get you to 100's of ps per bit.  That
 is more resolution (it's  1 ns) than you need for this.
 
 Getting an ADC to sample fast and accurately enough to provide that
 honest resolution is not trivial.  And if you have that, you'll
 almost certainly have the resources to do the phase comparator
 digitally, too, which brings many advantages -- so I see no reason
 to use an analog PC.
 
 If you take a look at some of the newer ARM MCU’s they are getting
 13+ solid bits out of their ADC’s at a  10 KHz rate. That’s more
 than good enough for anything you are trying to do with this design.
 There’s no need to make it any more complex.
 
 I'm using the Freescale Kinetix K20 parts, which have 16 bit differential 
 input ADCs, and built in averaging.  The raw ADC can sample at about 400kHz.
 
 You can easily get 14 bit performance from these at tens of kHz rates.
 I need I/Q, so I sample two inputs at 50 kHz (read one, then the other) 
 without averaging (so they're about 2.5 microseconds apart), and then 
 decimate them through a 2 stage CIC and a 13 tap FIR filter down to 200 Hz.  
 This takes about 60% of the processor running at 48MHz.

I’m using parts from the same family, but not doing the whole DDS thing. Single 
input and control loop - the part sleeps about 98% of the time. The demo boards 
(Freedom boards) are all below $15 and free if you go to one of their (often 
free) classes. 

Bob

 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-19 Thread Chris Albertson

At the low end of the spectrum, I tried to make the simplest possible
GPSDO what would still work.  Assuming you have a GPS with  1PPS
output, an OCXO and a small DC power supply I was able to get the
entire parts for the controller, board, hookup wire and all for under
$5.  I purposely took the lowest cost solution at each decision point
just to see what you'd end up with.   Part were from eBay.

The result is not bad. but I don't have a really good way to test it.
I'm using a Thunderbolt for the 1PPS and a pretty decent OXCO part.
Why build a low-end GPSDO when yo have a Thunderbolt?  It's and
experiment.   The way I test is to place the sine output from the TB
and from my GPSDO both on a dual channel scope and adjust it so the
two sine waves are superimposed.   Then I wait for them not to be
superimposed.  What I see is that over 1/2 hour or so they get
slightly out of phase but then drift back in phase,  This happens
cyclically.   It is because of the VERY simply controller.  I tried to
minimize lines of C++ code.  It's running about 16 lines of code, more
or less.  Using my counter I think the GPSDO is good to  1E-10.

Rather than using a $15 ARM MCU board I used a $3 AVR board and used
100% 16-bit integer math in a very simple control loop.  There is one
external chip because the little AVR could not deal with the 10MHz
signal from the OCXO so I used a divider chip.  I use two 8-bit DACs
to control the EFC on the OCXO.  One is curse adjustment, one fine.
Added with a resister network and an RC filter with almost a 1 second
time constant.

If you can spend $35 you can build a very sophisticated controller
that logs internal diagnostic data to a computer over USB and displays
it's internal status on a graphic LCD panel.   Well, actually my
controller has an LCD status display and logs data to a PC.  But with
those parts plugged in the cost is closer to $10.

On Sun, Oct 19, 2014 at 2:13 PM, Bob Camp kb...@n1k.org wrote:
 Hi

 On Oct 19, 2014, at 5:00 PM, Jim Lux jim...@earthlink.net wrote:

 On 10/19/14, 1:08 PM, Bob Camp wrote:
 Hi

 On Oct 19, 2014, at 3:35 PM, Charles Steinmetz
 csteinm...@yandex.com wrote:

 Bob wrote (alluding also to something Poul-Henning wrote):

 The phase comparison part of the PLL is pretty straightforward if
 you are looking at two RF frequencies. An XOR gate is one
 solution, there are many others. Getting something like 100 to
 200 ns full scale on the phase comparator makes the rest of the
 gizmo much easier.

 All true.  However...

 A 12 bit ADC on a MCU will get you to 100's of ps per bit.  That
 is more resolution (it's  1 ns) than you need for this.

 Getting an ADC to sample fast and accurately enough to provide that
 honest resolution is not trivial.  And if you have that, you'll
 almost certainly have the resources to do the phase comparator
 digitally, too, which brings many advantages -- so I see no reason
 to use an analog PC.

 If you take a look at some of the newer ARM MCU’s they are getting
 13+ solid bits out of their ADC’s at a  10 KHz rate. That’s more
 than good enough for anything you are trying to do with this design.
 There’s no need to make it any more complex.

 I'm using the Freescale Kinetix K20 parts, which have 16 bit differential 
 input ADCs, and built in averaging.  The raw ADC can sample at about 400kHz.

 You can easily get 14 bit performance from these at tens of kHz rates.
 I need I/Q, so I sample two inputs at 50 kHz (read one, then the other) 
 without averaging (so they're about 2.5 microseconds apart), and then 
 decimate them through a 2 stage CIC and a 13 tap FIR filter down to 200 Hz.  
 This takes about 60% of the processor running at 48MHz.

 I’m using parts from the same family, but not doing the whole DDS thing. 
 Single input and control loop - the part sleeps about 98% of the time. The 
 demo boards (Freedom boards) are all below $15 and free if you go to one of 
 their (often free) classes.

 Bob

 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.



-- 

Chris Albertson
Redondo Beach, California
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-19 Thread Bert Kehren via time-nuts

We did the same using a 1 KHz out of the $ 14 ubolx M7 and a Morion .  
Results better than 1 E-10. Some time nuts are now assembling and testing the  
same. Total cost less than $ 10 not counting OCXO or GPS. Most expensive item 
is  the filter capacitor.
Bert Kehren
 
 
In a message dated 10/19/2014 6:15:06 P.M. Eastern Daylight Time,  
albertson.ch...@gmail.com writes:

At the  low end of the spectrum, I tried to make the simplest possible
GPSDO what  would still work.  Assuming you have a GPS with  1PPS
output, an  OCXO and a small DC power supply I was able to get the
entire parts for the  controller, board, hookup wire and all for under
$5.  I purposely took  the lowest cost solution at each decision point
just to see what you'd end  up with.   Part were from eBay.

The result is not bad. but I  don't have a really good way to test it.
I'm using a Thunderbolt for the  1PPS and a pretty decent OXCO part.
Why build a low-end GPSDO when yo have  a Thunderbolt?  It's and
experiment.   The way I test is to  place the sine output from the TB
and from my GPSDO both on a dual channel  scope and adjust it so the
two sine waves are superimposed.Then I wait for them not to be
superimposed.  What I see is that over  1/2 hour or so they get
slightly out of phase but then drift back in  phase,  This happens
cyclically.   It is because of the VERY  simply controller.  I tried to
minimize lines of C++ code.  It's  running about 16 lines of code, more
or less.  Using my  counter I think the GPSDO is good to  1E-10.

Rather than using a  $15 ARM MCU board I used a $3 AVR board and used
100% 16-bit integer math  in a very simple control loop.  There is one
external chip because the  little AVR could not deal with the 10MHz
signal from the OCXO so I used a  divider chip.  I use two 8-bit DACs
to control the EFC on the  OCXO.  One is curse adjustment, one fine.
Added with a resister  network and an RC filter with almost a 1 second
time constant.

If  you can spend $35 you can build a very sophisticated controller
that logs  internal diagnostic data to a computer over USB and displays
it's internal  status on a graphic LCD panel.   Well, actually my
controller has  an LCD status display and logs data to a PC.  But with
those parts  plugged in the cost is closer to $10.

On Sun, Oct 19, 2014 at 2:13 PM,  Bob Camp kb...@n1k.org wrote:
 Hi

 On Oct  19, 2014, at 5:00 PM, Jim Lux jim...@earthlink.net  wrote:

 On 10/19/14, 1:08 PM, Bob Camp  wrote:
 Hi

 On Oct 19, 2014,  at 3:35 PM, Charles Steinmetz
  csteinm...@yandex.com wrote:

  Bob wrote (alluding also to something Poul-Henning  wrote):

 The phase comparison part  of the PLL is pretty straightforward if
 you are  looking at two RF frequencies. An XOR gate is one
  solution, there are many others. Getting something like 100  to
 200 ns full scale on the phase comparator makes the  rest of the
 gizmo much  easier.

 All true.   However...

 A 12 bit ADC on a MCU  will get you to 100's of ps per bit.  That
 is  more resolution (it's  1 ns) than you need for  this.

 Getting an ADC to sample fast  and accurately enough to provide that
 honest resolution is  not trivial.  And if you have that, you'll
 almost  certainly have the resources to do the phase comparator
  digitally, too, which brings many advantages -- so I see no  reason
 to use an analog  PC.

 If you take a look at some of the newer  ARM MCU’s they are getting
 13+ solid bits out of their ADC’s  at a  10 KHz rate. That’s more
 than good enough for  anything you are trying to do with this design.
 There’s no  need to make it any more complex.

 I'm using the  Freescale Kinetix K20 parts, which have 16 bit 
differential input ADCs, and  built in averaging.  The raw ADC can sample at 
about  
400kHz.

 You can easily get 14 bit performance from  these at tens of kHz rates.
 I need I/Q, so I sample two inputs at  50 kHz (read one, then the other) 
without averaging (so they're about 2.5  microseconds apart), and then 
decimate them through a 2 stage CIC and a 13 tap  FIR filter down to 200 Hz.  
This takes about 60% of the processor running  at 48MHz.

 I’m using parts from the same family, but not doing  the whole DDS thing. 
Single input and control loop - the part sleeps about 98%  of the time. The 
demo boards (Freedom boards) are all below $15 and free if  you go to one 
of their (often free) classes.

  Bob

  ___
 time-nuts mailing  list -- time-nuts@febo.com
 To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow  the instructions there.

  ___
 time-nuts mailing list  -- time-nuts@febo.com
 To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the  instructions there.



-- 

Chris Albertson
Redondo  Beach,  California
___
time-nuts  mailing list -- time-nuts@febo.com
To unsubscribe, go to

Re: [time-nuts] LTE-Lite module

2014-10-18 Thread Dr. David Kirkby (Kirkby Microwave Ltd)

We seem to have swung from “it’s impossible, don’t even try” to “it’s trivial,
you should have it done in a few minutes” :) (Yes I know that’s *not* at all
what was said in either case. We have swung a ways though)

Yes, I can do it for less than $1 in parts. That’s not to say it’s the *right*
way to do it. Yes, I can have it “done (locked up) in a few hours (from
scratch, including the parts). That’s not to say you *should* do it that way.
My way most certainly should not be your way. The stuff I have sitting around
is not the stuff you have lying around. What I paid may not be what you pay.

We spend a lot of time playing “I can do it cheaper”. Unless a few months of
your time *really* is worth $10, the “cheaper” part simply does not count past
some point. The cost of even one meal out over several months will wipe out
that advantage. Doing it with a part that is running a 10 bit ADC that really
gives you 8 bit performance will indeed impact the result. It’s cheaper, but
how much struggle will there be to make it work well? Will it add a month or
three to the project? Will you start over from scratch? Who knows. Are we
comparing a board anybody can get for $15 to just the cpu on another board ..
maybe we are. If what counts is a price that somebody got once, I have boards
that I got for free. Do they count as $0 in a project? There’s really no value
even going down that road.

Each time this comes up on the list, we typically spend a month with everybody
tossing up their favorite board. We each post several messages talking about
the great deal we got. We never seem to get around to actually doing much with
those cheap boards compared to the time everybody spends extolling their
virtues (and ignoring their drawbacks). A $50 board is no different than a $1
board in this case. They both have near zero impact on the total investment in
the project. If they did / do - buy a $135 OCXO based GPSDO rather than the
$185 LTE board. That puts you $50 and months of your time ahead.

If you want to start from scratch and get a result that is “OCXO” caliber, it
will take a while. 1x10^-10 is not your target. The LTE part pretty much does
that. Your target is at least 1x10^-11 short term and much better a you go to a
few hundred seconds. In order to say you have hit it, you need to test it and
verify that you have hit it. No I can’t do a run that takes a month to verify a
part I build in a short time.Nobody can do that, it takes time. No I don’t have
a gizmo that’ stable to 1x10^-13 over a month sitting in the basement. If I
already had that, why would I need to put an OCXO on a LTE board? I have to do
some work simply to do the test (like build several and cross check them).

How much time does the testing take? You want something around 100 samples for
a good ADEV number. You need data out to 1,000 seconds (and more likely 10,000
seconds) to check the loop out. Each run will be in the 1 to 10 days range.
Once you have it “right” you really need to check it over a month or two to
watch for GPS “once a day” issues. If you have a really good setup, you will
get good data 4 runs out of 5. With a basement setup, that may drop to 2 in 5.

The job is not done once the first one is locked. That’s the quick and easy
part. The full job is only done once you have it optimized and know you have
done so from measured data. That’s true if you are making one, or making a few
hundred thousand of them.

Bob

On Oct 19, 2014, at 6:14 PM, Chris Albertson albertson.ch...@gmail.com
wrote:

At the low end of the spectrum, I tried to make the simplest possible
GPSDO what would still work. Assuming you have a GPS with 1PPS
output, an OCXO and a small DC power supply I was able to get the
entire parts for the controller, board, hookup wire and all for under
$5. I purposely took the lowest cost solution at each decision point
just to see what you'd end up with. Part were from eBay.

The result is not bad. but I don't have a really good way to test it.
I'm using a Thunderbolt for the 1PPS and a pretty decent OXCO part.
Why build a low-end GPSDO when yo have a Thunderbolt? It's and
experiment. The way I test is to place the sine output from the TB
and from my GPSDO both on a dual channel scope and adjust it so the
two sine waves are superimposed. Then I wait for them not to be
superimposed. What I see is that over 1/2 hour or so they get
slightly out of phase but then drift back in phase, This happens
cyclically. It is because of the VERY simply controller. I tried to
minimize lines of C++ code. It's running about 16 lines of code, more
or less. Using my counter I think the GPSDO is good to 1E-10.

Rather than using a $15 ARM MCU board I used a $3 AVR board and used
100% 16-bit integer math in a very simple control loop. There is one
external chip because the little AVR could not deal with the 10MHz
signal from the OCXO so I used a

Re: [time-nuts] LTE-Lite module

2014-10-18 Thread Jim Sanford

I look forward to the app note.  Might be the incentive to get me to 
actually USE the Express PCB software I have.

Jim

On 10/17/2014 4:40 PM, S. Jackson via time-nuts wrote:

Hi there,
  
I don't know how much the Wenzel units are, but if someone is not able  to,

or willing to build one on their own then this could be a  viable
alternative.
  
I will look into writing a short appnote describing how a low-noise

div-by-2 can be built at home with minimal components using a surface mount '74
chip and a couple of passives.
  
Lastly the 20MHz LTE-Lite boards do generate a 10MHz output of course, and

if you feed that into a standard counter (5370B, 53132A etc etc) I  think
the noise floor of the counter would be higher than the  noise floor of the
synthesized 10MHz output, so you would not see any difference  between using
the noisier synthesized output and the low-noise 10MHz TCXO  divided output..
  
Bye,

Said
  
  
In a message dated 10/17/2014 13:19:08 Pacific Daylight Time,

gign...@gmail.com writes:

How much would we guess that Wenzel blue-top would run you?


Relative to the low cost GPSDO,  my understanding is the Wenzel  parts are
priced appropriately to their quality.






On Fri, Oct 17, 2014 at 11:32 AM, S. Jackson via  time-nuts
_time-nuts@febo.com_ (mailto:time-nuts@febo.com)  wrote:


Hello  Jim,
let me answer through Time Nuts as this may interest  other  parties as
well.
Yes, using a fast flip flop to generate 10MHz out  of  the 20MHz TCXO 3.0V
CMOS output from the LTE-Lite module will  preserve the phase  noise
(actually
improve it by up to 6dB due to  the 20log(n/m) noise improvement)  and will
not add any spurs if you  use the clean 3.0V output from the LTE-Lite
module
or an external  clean power supply (please note the LTE-Lite TCXO RF  output
is 3.0V  due to the internal 3.3V to 3.0V Low Noise regulator feeding the
TCXO and  buffer).
Use fast logic such as 74AC74, 74FCT74, or the like.  We do  exactly that on
our ULN-2550 boards to generate 50MHz and 25MHz out of  the  100MHz, and
using a fast CMOS divider will result in additive  phase noise  that will be
below the crystal oscillator phase noise  floor.
That will result in significantly better phase noise and   much lower spurs
than using the synthesized 10MHz output from the board,  and one  74' chip
can generate both 10MHz and 5MHz out of the 20MHz  LTE-Lite output. This  is
exactly what we would do here if we needed  a clean 10MHz from the 20MHz
LTE-Lite board.
I believe you can order  low-noise divide-by-2  blue-top boxes from Wenzel
already  packaged-up and connectorized as  well.
Hope that  helps,
Said
Hi Said
I was one of those looking for 10Mhz but I just  thought  again now that it
might be just as well to divide the  standard 20Mhz output by 2  using a FF.
I think that would preserve  all the desirable characteristics of the  20Mhz
signal which I  understand to just be square wave at CMOS 3.3v levels
anyway. Is that  correct?
Thanks
Jim
___
time-nuts  mailing list -- _time-nuts@febo.com_ (mailto:time-nuts@febo.com)
To unsubscribe,  go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and  follow the instructions  there.





___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.




---
This email is free from viruses and malware because avast! Antivirus protection 
is active.
http://www.avast.com

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

On 17 Oct 2014 19:33, S. Jackson via time-nuts time-nuts@febo.com wrote:


 Hello Jim,
 let me answer through Time Nuts as this may interest  other parties as
 well.
 Yes, using a fast flip flop to generate 10MHz out of  the 20MHz TCXO 3.0V
 CMOS output from the LTE-Lite module will preserve the phase  noise
(actually
 improve it by up to 6dB due to the 20log(n/m) noise improvement)

Hi Said,

I am only looking for a good clean 10 MHz reference for my lab to feed into
instruments like my SA, VNA, signal generator etc. Would I be right in
concluding the best way to achieve this is to use the 20 MHz version and
the simple divide by 2 that you showed?

I was going to place an order for the 10 MHz version, despite the long lead
time, but if I understand you correctly I would get better performance in
less time by going for the 20 MHz version and a ÷2.

The other thing I am not so sure about is what the specification of the
external TCXO/OCXO needs to be. I gather it is 3.3 V, but does it need to
generate a sine or square wave? What amolitude? I was wondering if there
would be some advantage in using a 10 MHz OCXO, such as an HP 10811A rather
than the inbuilt TCXO. Without knowing what your board expects to see, it
is impossible to know what to type to add.

Dave



and will
 not add any spurs if you use the clean 3.0V output from the LTE-Lite
module
 or an external clean power supply (please note the LTE-Lite TCXO RF
output
 is 3.0V due to the internal 3.3V to 3.0V Low Noise regulator feeding the
 TCXO and buffer).
 Use fast logic such as 74AC74, 74FCT74, or the like.

We do exactly that on
 our ULN-2550 boards to generate 50MHz and 25MHz out of the  100MHz, and
 using a fast CMOS divider will result in additive phase noise  that will
be
 below the crystal oscillator phase noise floor.
 That will result in significantly better phase noise and  much lower spurs
 than using the synthesized 10MHz output from the board, and one  74' chip
 can generate both 10MHz and 5MHz out of the 20MHz LTE-Lite output. This
is
 exactly what we would do here if we needed a clean 10MHz from the 20MHz
 LTE-Lite board.
 I believe you can order low-noise divide-by-2  blue-top boxes from Wenzel
 already packaged-up and connectorized as  well.
 Hope that helps,
 Said
 Hi Said
 I was one of those looking for 10Mhz but I just thought  again now that it
 might be just as well to divide the standard 20Mhz output by 2  using a
FF.
 I think that would preserve all the desirable characteristics of the
20Mhz
 signal which I understand to just be square wave at CMOS 3.3v levels
 anyway. Is that correct?
 Thanks
 Jim
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-18 Thread Bob Camp

Hi

For a lab reference, “clean” is a relative term. Most (as in every one I’ve 
ever seen) instruments expect a dirty signal on the reference input. They phase 
lock an internal oscillator to clean it up. Past some (unfortunately variable) 
offset, the reference signal has no impact on the instrument at all. In most 
cases, that offset is below 50 Hz in order to reject power line induced spurs 
on the reference signal. Yes, phase noise inside 10 or 20 Hz may matter. ADEV 
at 1 sec and longer is probably a better thing to look at. 

How good does it need to be? Most counters are quite happy with an ADEV at the 
1x10^-11 level at 1 second. VNA’s and spectrum analyzers will be happy with 
something even less stable. Synthesizers will (ultimately) pass along what ever 
is on the reference to the output. Your specific test application will dictate 
if a 1x10^-12 wander at 100,000 seconds on your synthesizer is important or 
not. 

Bob

 On Oct 18, 2014, at 9:34 AM, Dr. David Kirkby (Kirkby Microwave Ltd) 
 drkir...@kirkbymicrowave.co.uk wrote:
 
 On 17 Oct 2014 19:33, S. Jackson via time-nuts time-nuts@febo.com wrote:
 
 
 Hello Jim,
 let me answer through Time Nuts as this may interest  other parties as
 well.
 Yes, using a fast flip flop to generate 10MHz out of  the 20MHz TCXO 3.0V
 CMOS output from the LTE-Lite module will preserve the phase  noise
 (actually
 improve it by up to 6dB due to the 20log(n/m) noise improvement)
 
 Hi Said,
 
 I am only looking for a good clean 10 MHz reference for my lab to feed into
 instruments like my SA, VNA, signal generator etc. Would I be right in
 concluding the best way to achieve this is to use the 20 MHz version and
 the simple divide by 2 that you showed?
 
 I was going to place an order for the 10 MHz version, despite the long lead
 time, but if I understand you correctly I would get better performance in
 less time by going for the 20 MHz version and a ÷2.
 
 The other thing I am not so sure about is what the specification of the
 external TCXO/OCXO needs to be. I gather it is 3.3 V, but does it need to
 generate a sine or square wave? What amolitude? I was wondering if there
 would be some advantage in using a 10 MHz OCXO, such as an HP 10811A rather
 than the inbuilt TCXO. Without knowing what your board expects to see, it
 is impossible to know what to type to add.
 
 Dave
 
 
 
 and will
 not add any spurs if you use the clean 3.0V output from the LTE-Lite
 module
 or an external clean power supply (please note the LTE-Lite TCXO RF
 output
 is 3.0V due to the internal 3.3V to 3.0V Low Noise regulator feeding the
 TCXO and buffer).
 Use fast logic such as 74AC74, 74FCT74, or the like.
 
 We do exactly that on
 our ULN-2550 boards to generate 50MHz and 25MHz out of the  100MHz, and
 using a fast CMOS divider will result in additive phase noise  that will
 be
 below the crystal oscillator phase noise floor.
 That will result in significantly better phase noise and  much lower spurs
 than using the synthesized 10MHz output from the board, and one  74' chip
 can generate both 10MHz and 5MHz out of the 20MHz LTE-Lite output. This
 is
 exactly what we would do here if we needed a clean 10MHz from the 20MHz
 LTE-Lite board.
 I believe you can order low-noise divide-by-2  blue-top boxes from Wenzel
 already packaged-up and connectorized as  well.
 Hope that helps,
 Said
 Hi Said
 I was one of those looking for 10Mhz but I just thought  again now that it
 might be just as well to divide the standard 20Mhz output by 2  using a
 FF.
 I think that would preserve all the desirable characteristics of the
 20Mhz
 signal which I understand to just be square wave at CMOS 3.3v levels
 anyway. Is that correct?
 Thanks
 Jim
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Hi guys,
 
lots of questions, let me try to answer some of these. Bob, David, et. al,  
thanks for answering some of these already!
 
Dave, as Bob said it depends on your application -- and your time frame.  
Also, please check the FAQ for an answer on the external TCXO requirement,  
specifically item 35. in the FAQ on the Ebay website for the product.
 
Jim, I ended up doing the appnote in email format, and sending out a  
description, schematics, PN plot, and photos yesterday, please check your  
emails. I won't do a formal appnote, sorry no time.. I hope the description of  
what I wired-up yesterday is good enough for folks to try the same.
 
Ernie, as mentioned here the price is $185 plus shipping on Ebay for the  
entire kit. Shipping is calculated by Ebay, and should be a flat-rate  of $10 
in the continental US
 
Hal, MY BAD!! I should have known better and super-imposed both the  
original 20MHz and 10MHz plots on the same plot. I will do so shortly. On the  
table in the plot: the TimePod tries to determine spurs, and display them  on 
the upper right hand of the plot in a table, and with the phase noise being  
as clean as it is I guess the TimePod software could only find two spurs, 
one at  0.8 and one at 0.9Hz offset from carrier, which was not even shown in 
that plot  since it starts at 1Hz.
 
Thanks so much for your feedback, lively discussion, and good questions  
guys.
 
I hope that answers all questions,
bye,
Said
 
 
In a message dated 10/18/2014 10:43:40 Pacific Daylight Time, kb...@n1k.org 
 writes:

Hi

For a lab reference, “clean” is a relative term. Most (as  in every one I’
ve ever seen) instruments expect a dirty signal on the  reference input. 
They phase lock an internal oscillator to clean it up. Past  some 
(unfortunately variable) offset, the reference signal has no impact on  the 
instrument at 
all. In most cases, that offset is below 50 Hz in order to  reject power 
line induced spurs on the reference signal. Yes, phase noise  inside 10 or 20 
Hz may matter. ADEV at 1 sec and longer is probably a better  thing to look 
at. 

How good does it need to be? Most counters are quite  happy with an ADEV at 
the 1x10^-11 level at 1 second. VNA’s and spectrum  analyzers will be happy 
with something even less stable. Synthesizers will  (ultimately) pass along 
what ever is on the reference to the output. Your  specific test 
application will dictate if a 1x10^-12 wander at 100,000 seconds  on your 
synthesizer 
is important or not. 

Bob

 On Oct 18,  2014, at 9:34 AM, Dr. David Kirkby (Kirkby Microwave Ltd)  
drkir...@kirkbymicrowave.co.uk wrote:
 
 On 17 Oct 2014  19:33, S. Jackson via time-nuts time-nuts@febo.com  
wrote:
 
 
 Hello Jim,
 let me  answer through Time Nuts as this may interest  other parties  as
 well.
 Yes, using a fast flip flop to generate 10MHz  out of  the 20MHz TCXO 
3.0V
 CMOS output from the LTE-Lite  module will preserve the phase  noise
 (actually
  improve it by up to 6dB due to the 20log(n/m) noise improvement)
  
 Hi Said,
 
 I am only looking for a good clean 10 MHz  reference for my lab to feed 
into
 instruments like my SA, VNA, signal  generator etc. Would I be right in
 concluding the best way to achieve  this is to use the 20 MHz version and
 the simple divide by 2 that you  showed?
 
 I was going to place an order for the 10 MHz version,  despite the long 
lead
 time, but if I understand you correctly I would  get better performance in
 less time by going for the 20 MHz version  and a ÷2.
 
 The other thing I am not so sure about is what the  specification of the
 external TCXO/OCXO needs to be. I gather it is  3.3 V, but does it need to
 generate a sine or square wave? What  amolitude? I was wondering if there
 would be some advantage in using a  10 MHz OCXO, such as an HP 10811A 
rather
 than the inbuilt TCXO.  Without knowing what your board expects to see, it
 is impossible to  know what to type to add.
 
 Dave
 
 
  
 and will
 not add any spurs if you use the clean 3.0V  output from the LTE-Lite
 module
 or an external clean power  supply (please note the LTE-Lite TCXO RF
 output
 is 3.0V  due to the internal 3.3V to 3.0V Low Noise regulator feeding the
  TCXO and buffer).
 Use fast logic such as 74AC74, 74FCT74, or the  like.
 
 We do exactly that on
 our ULN-2550 boards  to generate 50MHz and 25MHz out of the  100MHz, and
 using a  fast CMOS divider will result in additive phase noise  that will
  be
 below the crystal oscillator phase noise floor.
  That will result in significantly better phase noise and  much lower  
spurs
 than using the synthesized 10MHz output from the board, and  one  74' 
chip
 can generate both 10MHz and 5MHz out of the  20MHz LTE-Lite output. This
 is
 exactly what we would do  here if we needed a clean 10MHz from the 20MHz
 LTE-Lite  board.
 I believe you can order low-noise divide-by-2   blue-top boxes from 
Wenzel
 already packaged-up and connectorized  as  well.
 Hope that helps,
 Said
 Hi  Said
 I was

[time-nuts] LTE-Lite module

 
Guys, 
we have been getting a good number of emails with questions  that have 
already been addressed in the user manual or the FAQ, see the  below link. We 
spent a lot of time putting the collateral together, may I please  ask that 
you first look into these two documents to see if your question might  already 
be addressed there? 
Paul, 
please search the LTE Lite user manual for Hammond and you will  find it 
there: 
http://www.jackson-labs.com/index.php/products/lte_lite 
Thanks,
Said 
_ 
Do you have a recommended Hammond chassis part  number? 
-- 
Paul
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Hal,
 
attached is the superimposed plot of the standard 20MHz TCXO Phase  Noise 
and the 10MHz output of my bare-bones divide by 2 flip-flop. The green  trace 
is the new 20MHz plot, the blue the one I had sent out yesterday at 10MHz,  
both sourced from the same TCXO.
 
 
You can nicely see that the noise improves by almost exactly  6dB at 100Hz 
just as theory would have it. One problem is that my  reference has only a 
noise floor of about -160dBc/Hz at 10MHz, so when I  measure 20MHz signals 
that actually degrades to the equivalent of  -154dBc/Hz due to the reference 
noise floor.
 
 
Are these plots going to be the same on all the boards? No, these are  
typical plots for the particular random unit I tested here, and my particular  
test setup. Some of the units will have better noise, some worse. The 
variations  in performance from crystal to crystal have been discussed here on 
this 
 email list many times in the past.
 
 
BTW: we recently noticed a very peculiar caveat:
 
 
When plugging in the external TCXO (and by the way we decided to mount  a 
TCXO socket on every one of the eval kits to make life easier for everyone)  
and running from the external TCXO there could be a beat frequency from the  
internal TCXO, because while the output of the internal TCXO is disabled, 
the  crystal itself is still powered up and running and thus causing a slight 
 interference with the external TCXO.
 
What happens when an external 10MHz TCXO is plugged in with the internal  
20MHz TCXO is that there is harmonic mixing at 20MHz, 30MHz etc, and due to 
the  fact that only the external TCXO is disciplined (the internal TCXO gets 
the same  exact EFC voltage but will run at a harmonic offset of typically 
many  hertz) there is a beat frequency that results.
 
On our particular unit with 20MHz internal TCXO and 10MHz external TCXO  
that beat frequency happens to be about 10Hz between the two crystals. So this 
 results in a number of fairly strong spurs at 10Hz, 20Hz, 30Hz, etc etc  
offsets from the carrier.
 
To fix that issue there are two solutions:
 
1) Use an external TCXO that is not harmonically related to the internal  
TCXO. Such as 10MHz on a 19.2MHz board, or 15.36MHz on a 20MHz board. I 
realize  that this may not be practical
 
2) remove the internal TCXO carefully with a heat-gun when using the  
external TCXO
 
Unfortunately we have no way to power-off the internal TCXO completely, and 
 we cannot avoid physics..
 
The 10MHz boards with external TCXO won't have this problem as there will  
not be a small SMT TCXO mounted on the LTE-Lite module itself, so no 
harmonic  mixing will happen.
 
Bye,
Said
 
 
In a message dated 10/18/2014 00:36:27 Pacific Daylight Time,  
hmur...@megapathdsl.net writes:

  Here is the resulting 10MHz phase noise plot from the 20MHz TCXO   
output:

There is a box in the upper right that says -76.8 dBc at 0.8 Hz  and -85 
dBc 
at 0.9 Hz.  I can't make sense out of that.  It's  off scale to the left of 
the plot, but looks like it would be higher than  those values.

It would be neat to see the phase noise of the un-divided  20 Mhz OSC and 
also 
the 10 MHz OSC.



-- 
These are my  opinions.  I hate  spam.






LTE_10MHz_divide-by-2_PN_and-20MHz.png
Description: Binary data
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-18 Thread Dr. David Kirkby (Kirkby Microwave Ltd)

Guys,
 
one last email. The board will not fit into the Hammond enclosure without  
reworking the enclosure or removing the TCXO socket. We initially planned to 
 ship the board without the socket, now all of them will have it. The  
board was designed to be used without the TCXO/Socket to fit into that  
enclosure.

Caveat: please expect some rework to be necessary when using the  suggested 
Hammond enclosure.
 
bye,
Said
 
 
In a message dated 10/18/2014 12:56:06 Pacific Daylight Time,  
time-nuts@febo.com writes:


Guys, 
we have been getting a good number of emails with  questions  that have 
already been addressed in the user manual or the  FAQ, see the  below link. 
We 
spent a lot of time putting the  collateral together, may I please  ask 
that 
you first look into these  two documents to see if your question might  
already 
be addressed  there? 
Paul, 
please search the LTE Lite user manual for Hammond and  you will  find it 
there:  
http://www.jackson-labs.com/index.php/products/lte_lite  
Thanks,
Said 
_ 
Do you have a recommended  Hammond chassis part  number? 
--  
Paul
___
time-nuts  mailing list -- time-nuts@febo.com
To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the  instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-18 Thread Jim Sanford


Said:
Your email app note was VERY clear, thanks.

You also mentioned somewhere that the synthesizer output of 10 MHz is 
cleaner than most freq counters, etc., need, so I will probably just use 
that for the test equipment.  I will use the 20 MHz as reference for 
microwave LOs, and will do the divide by two board so I have a good 10 
MHz reference as well.


I've already ordered, holding my breath for arrival!

Thanks,
Jim

On 10/18/2014 2:19 PM, S. Jackson via time-nuts wrote:

Hi guys,
  
Jim, I ended up doing the appnote in email format, and sending out a

description, schematics, PN plot, and photos yesterday, please check your
emails. I won't do a formal appnote, sorry no time.. I hope the description of
what I wired-up yesterday is good enough for folks to try the same.
  




---
This email is free from viruses and malware because avast! Antivirus protection 
is active.
http://www.avast.com

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-18 Thread Said Jackson via time-nuts

Hi Bill,

I think it makes perfect sense. But I have no idea how the units' loop 
stability would be with the 10811. That kind of testing is on the plate.

You would preferably set the OCXO to a nominal tuning voltage of 1.5V using the 
mechanical adjustment, then let the LTE Lite do the rest.

Please note that the LTE board will auto-sense the external ocxo frequency, so 
any of the boards would work.

Please also note that due to the harmonic mixing issues I described earlier the 
best board to use for that setup would be the 19.2MHz version(!) or to remove 
the on-board tcxo altogether.

Bye,
Said

Sent From iPhone

 On Oct 18, 2014, at 15:24, Bill Dailey docdai...@gmail.com wrote:
 
 Said,
 
 How tough would it be to mate the 10Mhz version up to a really good 10811?  I 
 have one that I acquired from Corby some time ago.  I was going to spin my 
 own but I wont realistically get to that with everything else I have going 
 on.  I was thinking of throwing the LTE-Lite and  the 10811 in a box.  I 
 woudl then have a stock fury, An enhanced OEM fury (datum-c) and then 
 this gadget with a 10-13 10811.  Let me know if this doesnt make sense.  I am 
 an amateur.
 
 Bill
 
 On Sat, Oct 18, 2014 at 5:13 PM, S. Jackson via time-nuts 
 time-nuts@febo.com wrote:
 Guys,
 
 one last email. The board will not fit into the Hammond enclosure without
 reworking the enclosure or removing the TCXO socket. We initially planned to
  ship the board without the socket, now all of them will have it. The
 board was designed to be used without the TCXO/Socket to fit into that
 enclosure.
 
 Caveat: please expect some rework to be necessary when using the  suggested
 Hammond enclosure.
 
 bye,
 Said
 
 
 In a message dated 10/18/2014 12:56:06 Pacific Daylight Time,
 time-nuts@febo.com writes:
 
 
 Guys,
 we have been getting a good number of emails with  questions  that have
 already been addressed in the user manual or the  FAQ, see the  below link.
 We
 spent a lot of time putting the  collateral together, may I please  ask
 that
 you first look into these  two documents to see if your question might
 already
 be addressed  there?
 Paul,
 please search the LTE Lite user manual for Hammond and  you will  find it
 there:
 http://www.jackson-labs.com/index.php/products/lte_lite
 Thanks,
 Said
 _
 Do you have a recommended  Hammond chassis part  number?
 --
 Paul
 ___
 time-nuts  mailing list -- time-nuts@febo.com
 To unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the  instructions there.
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
 
 
 
 -- 
 Doc
 
 Bill Dailey
 KXØO
  
 
 

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-18 Thread Bill Dailey

Said,

How tough would it be to mate the 10Mhz version up to a really good 10811?
I have one that I acquired from Corby some time ago.  I was going to spin
my own but I wont realistically get to that with everything else I have
going on.  I was thinking of throwing the LTE-Lite and  the 10811 in a
box.  I woudl then have a stock fury, An enhanced OEM fury (datum-c)
and then this gadget with a 10-13 10811.  Let me know if this doesnt make
sense.  I am an amateur.

Bill

On Sat, Oct 18, 2014 at 5:13 PM, S. Jackson via time-nuts 
time-nuts@febo.com wrote:

 Guys,

 one last email. The board will not fit into the Hammond enclosure without
 reworking the enclosure or removing the TCXO socket. We initially planned
 to
  ship the board without the socket, now all of them will have it. The
 board was designed to be used without the TCXO/Socket to fit into that
 enclosure.

 Caveat: please expect some rework to be necessary when using the  suggested
 Hammond enclosure.

 bye,
 Said


 In a message dated 10/18/2014 12:56:06 Pacific Daylight Time,
 time-nuts@febo.com writes:


 Guys,
 we have been getting a good number of emails with  questions  that have
 already been addressed in the user manual or the  FAQ, see the  below link.
 We
 spent a lot of time putting the  collateral together, may I please  ask
 that
 you first look into these  two documents to see if your question might
 already
 be addressed  there?
 Paul,
 please search the LTE Lite user manual for Hammond and  you will  find it
 there:
 http://www.jackson-labs.com/index.php/products/lte_lite
 Thanks,
 Said
 _
 Do you have a recommended  Hammond chassis part  number?
 --
 Paul
 ___
 time-nuts  mailing list -- time-nuts@febo.com
 To unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the  instructions there.

 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.




-- 
Doc

Bill Dailey
KXØO
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

I am sorry, but I can't follow the circuit diagram.  It is not clear to me
what pins are joined,  and what are not. Sometimes you have used a filled
circle to indicate lines are joined,  and in another case there's a
semicircle to indicate that they are not. But on some of the others,  I
don't know what are supposed to be joined and what are not.

Dave
On 19 Oct 2014 01:00, S. Jackson via time-nuts time-nuts@febo.com wrote:

 Dave, et.al.,

 upon popular request I put together a PDF of my email describing how I
 generated a low-phase-noise 10MHz output from the CMOS 20MHz output of the
 LTE-Lite GPSDO. Here it is.

 No guarantees whatsoever guys, and it does take good equipment, a very
 steady hand, and a lot of experience to put this together and make it work
 properly.

 This design can work up to 145MHz according to the 74LVX74 datasheet if
 powered at 3.3V.

 bye,
 Said


 In a message dated 10/18/2014 14:09:54 Pacific Daylight Time,
 kc0...@gmail.com writes:

 Hi,  Said.

 I would be interested in having a copy of your app-note, if  that is
 possible. I'd like to purchase one of the GPSDOs, but will need to  wait
 for amonth or so.

 Thanks.

 Cheers,
 DaveD

 On  10/18/2014 12:19 PM, S. Jackson via time-nuts wrote:
  Hi  guys,
 
  lots of questions, let me try to answer  some of these. Bob, David, et.
 al,
  thanks for answering some of these  already!
 
  Dave, as Bob said it depends on your  application -- and your time
 frame.
  Also, please check the FAQ for an  answer on the external TCXO
 requirement,
  specifically item 35. in the  FAQ on the Ebay website for the product.
 
  Jim, I  ended up doing the appnote in email format, and sending out a
   description, schematics, PN plot, and photos yesterday, please check
 your
  emails. I won't do a formal appnote, sorry no time.. I hope the
 description of
  what I wired-up yesterday is good enough for folks to  try the same.
 
  Ernie, as mentioned here the price  is $185 plus shipping on Ebay for the
  entire kit. Shipping is  calculated by Ebay, and should be a flat-rate
 of $10
  in the  continental US
 
  Hal, MY BAD!! I should have known  better and super-imposed both the
  original 20MHz and 10MHz plots on  the same plot. I will do so shortly.
 On the
  table in the plot: the  TimePod tries to determine spurs, and display
 them  on
  the upper  right hand of the plot in a table, and with the phase noise
 being
  as  clean as it is I guess the TimePod software could only find two
 spurs,
   one at  0.8 and one at 0.9Hz offset from carrier, which was not even
 shown in
  that plot  since it starts at 1Hz.
 
  Thanks so much for your feedback, lively discussion, and good  questions
  guys.
 
  I hope that answers all  questions,
  bye,
   Said
 



 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-18 Thread Bob Camp

Hi

The 20 MHz connects only to pin 3.

+3V connects to pin 4 , but not pins 2 or 3.

Pin 6 hooks only to pin 2 and nothing else.

Bob


 On Oct 18, 2014, at 8:23 PM, Dr. David Kirkby (Kirkby Microwave Ltd) 
 drkir...@kirkbymicrowave.co.uk wrote:
 
 I am sorry, but I can't follow the circuit diagram.  It is not clear to me
 what pins are joined,  and what are not. Sometimes you have used a filled
 circle to indicate lines are joined,  and in another case there's a
 semicircle to indicate that they are not. But on some of the others,  I
 don't know what are supposed to be joined and what are not.
 
 Dave
 On 19 Oct 2014 01:00, S. Jackson via time-nuts time-nuts@febo.com wrote:
 
 Dave, et.al.,
 
 upon popular request I put together a PDF of my email describing how I
 generated a low-phase-noise 10MHz output from the CMOS 20MHz output of the
 LTE-Lite GPSDO. Here it is.
 
 No guarantees whatsoever guys, and it does take good equipment, a very
 steady hand, and a lot of experience to put this together and make it work
 properly.
 
 This design can work up to 145MHz according to the 74LVX74 datasheet if
 powered at 3.3V.
 
 bye,
 Said
 
 
 In a message dated 10/18/2014 14:09:54 Pacific Daylight Time,
 kc0...@gmail.com writes:
 
 Hi,  Said.
 
 I would be interested in having a copy of your app-note, if  that is
 possible. I'd like to purchase one of the GPSDOs, but will need to  wait
 for amonth or so.
 
 Thanks.
 
 Cheers,
 DaveD
 
 On  10/18/2014 12:19 PM, S. Jackson via time-nuts wrote:
 Hi  guys,
 
 lots of questions, let me try to answer  some of these. Bob, David, et.
 al,
 thanks for answering some of these  already!
 
 Dave, as Bob said it depends on your  application -- and your time
 frame.
 Also, please check the FAQ for an  answer on the external TCXO
 requirement,
 specifically item 35. in the  FAQ on the Ebay website for the product.
 
 Jim, I  ended up doing the appnote in email format, and sending out a
 description, schematics, PN plot, and photos yesterday, please check
 your
 emails. I won't do a formal appnote, sorry no time.. I hope the
 description of
 what I wired-up yesterday is good enough for folks to  try the same.
 
 Ernie, as mentioned here the price  is $185 plus shipping on Ebay for the
 entire kit. Shipping is  calculated by Ebay, and should be a flat-rate
 of $10
 in the  continental US
 
 Hal, MY BAD!! I should have known  better and super-imposed both the
 original 20MHz and 10MHz plots on  the same plot. I will do so shortly.
 On the
 table in the plot: the  TimePod tries to determine spurs, and display
 them  on
 the upper  right hand of the plot in a table, and with the phase noise
 being
 as  clean as it is I guess the TimePod software could only find two
 spurs,
 one at  0.8 and one at 0.9Hz offset from carrier, which was not even
 shown in
 that plot  since it starts at 1Hz.
 
 Thanks so much for your feedback, lively discussion, and good  questions
 guys.
 
 I hope that answers all  questions,
 bye,
 Said
 
 
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-18 Thread Tom Miller


This looks pretty interesting:
74G series PO74G74

http://www.ebay.com/itm/330551715157?_trksid=p2060778.m1438.l2649ssPageName=STRK%3AMEBIDX%3AIT#ht_411wt_664

600+ MHz cmos 3.5 volt

Tom


- Original Message - 
From: S. Jackson via time-nuts time-nuts@febo.com

To: kc0...@gmail.com; time-nuts@febo.com
Sent: Saturday, October 18, 2014 5:40 PM
Subject: Re: [time-nuts] LTE-Lite module



Dave, et.al.,

upon popular request I put together a PDF of my email describing how I
generated a low-phase-noise 10MHz output from the CMOS 20MHz output of the
LTE-Lite GPSDO. Here it is.

No guarantees whatsoever guys, and it does take good equipment, a very
steady hand, and a lot of experience to put this together and make it work
properly.

This design can work up to 145MHz according to the 74LVX74 datasheet if
powered at 3.3V.

bye,
Said


In a message dated 10/18/2014 14:09:54 Pacific Daylight Time,
kc0...@gmail.com writes:

Hi,  Said.

I would be interested in having a copy of your app-note, if  that is
possible. I'd like to purchase one of the GPSDOs, but will need to  wait
for amonth or so.

Thanks.

Cheers,
DaveD

On  10/18/2014 12:19 PM, S. Jackson via time-nuts wrote:

Hi  guys,

lots of questions, let me try to answer  some of these. Bob, David, et.

al,

thanks for answering some of these  already!

Dave, as Bob said it depends on your  application -- and your time

frame.

Also, please check the FAQ for an  answer on the external TCXO

requirement,

specifically item 35. in the  FAQ on the Ebay website for the product.

Jim, I  ended up doing the appnote in email format, and sending out a
 description, schematics, PN plot, and photos yesterday, please check

your

emails. I won't do a formal appnote, sorry no time.. I hope the

description of

what I wired-up yesterday is good enough for folks to  try the same.

Ernie, as mentioned here the price  is $185 plus shipping on Ebay for the
entire kit. Shipping is  calculated by Ebay, and should be a flat-rate

of $10

in the  continental US

Hal, MY BAD!! I should have known  better and super-imposed both the
original 20MHz and 10MHz plots on  the same plot. I will do so shortly.

On the

table in the plot: the  TimePod tries to determine spurs, and display

them  on

the upper  right hand of the plot in a table, and with the phase noise

being
as  clean as it is I guess the TimePod software could only find two 
spurs,

 one at  0.8 and one at 0.9Hz offset from carrier, which was not even

shown in

that plot  since it starts at 1Hz.

Thanks so much for your feedback, lively discussion, and good  questions
guys.

I hope that answers all  questions,
bye,
 Said












___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts

and follow the instructions there.



___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Thanks for helping out Bob,
 
sometimes I get ahead of myself.
 
Dave, you can also trace the wiring on the photo I had sent of the  actual 
module, its more or less clearly visible under the lupe. Please note that  
on that module I mounted the IC upside down, with the pins sticking up, and  
bending the grounded pins down toward the PCB.
 
bye,
Said
 
 
 
 
In a message dated 10/18/2014 17:55:36 Pacific Daylight Time, kb...@n1k.org 
 writes:

Hi


The 20 MHz connects only to pin 3.

+3V  connects to pin 4 , but not pins 2 or 3.

Pin 6 hooks only to pin 2 and  nothing else.

Bob


 On Oct 18, 2014, at 8:23 PM, Dr.  David Kirkby (Kirkby Microwave Ltd) 
drkir...@kirkbymicrowave.co.uk  wrote:
 
 I am sorry, but I can't follow the circuit  diagram.  It is not clear to 
me
 what pins are joined,  and  what are not. Sometimes you have used a filled
 circle to indicate  lines are joined,  and in another case there's a
 semicircle to  indicate that they are not. But on some of the others,  I
 don't  know what are supposed to be joined and what are not.
 
  Dave
 On 19 Oct 2014 01:00, S. Jackson via time-nuts  time-nuts@febo.com 
wrote:
 
 Dave,  et.al.,
 
 upon popular request I put together a PDF of  my email describing how I
 generated a low-phase-noise 10MHz output  from the CMOS 20MHz output of 
the
 LTE-Lite GPSDO. Here it  is.
 
 No guarantees whatsoever guys, and it does take  good equipment, a very
 steady hand, and a lot of experience to put  this together and make it 
work
 properly.
 
  This design can work up to 145MHz according to the 74LVX74 datasheet  if
 powered at 3.3V.
 
 bye,
  Said
 
 
 In a message dated 10/18/2014  14:09:54 Pacific Daylight Time,
 kc0...@gmail.com  writes:
 
 Hi,  Said.
 
 I  would be interested in having a copy of your app-note, if  that  is
 possible. I'd like to purchase one of the GPSDOs, but will need  to  wait
 for amonth or so.
 
  Thanks.
 
 Cheers,
 DaveD
  
 On  10/18/2014 12:19 PM, S. Jackson via time-nuts  wrote:
 Hi  guys,
 
 lots of  questions, let me try to answer  some of these. Bob, David,  
et.
 al,
 thanks for answering some of these   already!
 
 Dave, as Bob said it depends on  your  application -- and your time
 frame.
  Also, please check the FAQ for an  answer on the external  TCXO
 requirement,
 specifically item 35. in  the  FAQ on the Ebay website for the product.
  
 Jim, I  ended up doing the appnote in email format,  and sending out a
 description, schematics, PN plot, and photos  yesterday, please check
 your
 emails. I won't do a  formal appnote, sorry no time.. I hope the
 description  of
 what I wired-up yesterday is good enough for folks to   try the same.
 
 Ernie, as mentioned here the  price  is $185 plus shipping on Ebay for 
the
 entire kit.  Shipping is  calculated by Ebay, and should be a flat-rate
 of  $10
 in the  continental US
  
 Hal, MY BAD!! I should have known  better and  super-imposed both the
 original 20MHz and 10MHz plots on   the same plot. I will do so shortly.
 On the
 table  in the plot: the  TimePod tries to determine spurs, and  display
 them  on
 the upper  right hand  of the plot in a table, and with the phase noise
  being
 as  clean as it is I guess the TimePod software  could only find two
 spurs,
 one at  0.8 and  one at 0.9Hz offset from carrier, which was not even
 shown  in
 that plot  since it starts at 1Hz.
  
 Thanks so much for your feedback, lively discussion, and  good  
questions
 guys.
 
 I  hope that answers all  questions,
 bye,
  Said
 
 
 
 
  ___
 time-nuts mailing  list -- time-nuts@febo.com
 To unsubscribe, go to
  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow  the instructions there.
 
  ___
 time-nuts mailing list  -- time-nuts@febo.com
 To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the  instructions  there.

___
time-nuts  mailing list -- time-nuts@febo.com
To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the  instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-18 Thread Thomas S. Knutsen

The potatochips are quite excelent high speed devices, and by selling them
on e-bay, they make it avaible to us who are not able to go through the
normal supplier chains.

Br.
Thomas.

2014-10-19 2:48 GMT+02:00 Tom Miller tmiller11...@verizon.net:

 This looks pretty interesting:
 74G series PO74G74

 http://www.ebay.com/itm/330551715157?_trksid=p2060778.
 m1438.l2649ssPageName=STRK%3AMEBIDX%3AIT#ht_411wt_664

 600+ MHz cmos 3.5 volt

 Tom


 - Original Message - From: S. Jackson via time-nuts 
 time-nuts@febo.com
 To: kc0...@gmail.com; time-nuts@febo.com
 Sent: Saturday, October 18, 2014 5:40 PM
 Subject: Re: [time-nuts] LTE-Lite module



  Dave, et.al.,

 upon popular request I put together a PDF of my email describing how I
 generated a low-phase-noise 10MHz output from the CMOS 20MHz output of the
 LTE-Lite GPSDO. Here it is.

 No guarantees whatsoever guys, and it does take good equipment, a very
 steady hand, and a lot of experience to put this together and make it work
 properly.

 This design can work up to 145MHz according to the 74LVX74 datasheet if
 powered at 3.3V.

 bye,
 Said


 In a message dated 10/18/2014 14:09:54 Pacific Daylight Time,
 kc0...@gmail.com writes:

 Hi,  Said.

 I would be interested in having a copy of your app-note, if  that is
 possible. I'd like to purchase one of the GPSDOs, but will need to  wait
 for amonth or so.

 Thanks.

 Cheers,
 DaveD

 On  10/18/2014 12:19 PM, S. Jackson via time-nuts wrote:

 Hi  guys,

 lots of questions, let me try to answer  some of these. Bob, David, et.

 al,

 thanks for answering some of these  already!

 Dave, as Bob said it depends on your  application -- and your time

 frame.

 Also, please check the FAQ for an  answer on the external TCXO

 requirement,

 specifically item 35. in the  FAQ on the Ebay website for the product.

 Jim, I  ended up doing the appnote in email format, and sending out a
  description, schematics, PN plot, and photos yesterday, please check

 your

 emails. I won't do a formal appnote, sorry no time.. I hope the

 description of

 what I wired-up yesterday is good enough for folks to  try the same.

 Ernie, as mentioned here the price  is $185 plus shipping on Ebay for the
 entire kit. Shipping is  calculated by Ebay, and should be a flat-rate

 of $10

 in the  continental US

 Hal, MY BAD!! I should have known  better and super-imposed both the
 original 20MHz and 10MHz plots on  the same plot. I will do so shortly.

 On the

 table in the plot: the  TimePod tries to determine spurs, and display

 them  on

 the upper  right hand of the plot in a table, and with the phase noise

 being

 as  clean as it is I guess the TimePod software could only find two
 spurs,
  one at  0.8 and one at 0.9Hz offset from carrier, which was not even

 shown in

 that plot  since it starts at 1Hz.

 Thanks so much for your feedback, lively discussion, and good  questions
 guys.

 I hope that answers all  questions,
 bye,
  Said






 
 



  ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/
 mailman/listinfo/time-nuts
 and follow the instructions there.


 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/
 mailman/listinfo/time-nuts
 and follow the instructions there.




-- 

 Please  avoid sending  me  Word  or  PowerPoint  attachments.
 See  http://www.gnu.org/philosophy/no-word-attachments.html
PDF is an better alternative and there are always LaTeX!
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-18 Thread Bob Camp

Hi

Didn’t we just hash through all the Potato Chip stuff earlier this week when 
Bert brought them up?

Bob

 On Oct 18, 2014, at 9:51 PM, Thomas S. Knutsen la3...@gmail.com wrote:
 
 The potatochips are quite excelent high speed devices, and by selling them
 on e-bay, they make it avaible to us who are not able to go through the
 normal supplier chains.
 
 Br.
 Thomas.
 
 2014-10-19 2:48 GMT+02:00 Tom Miller tmiller11...@verizon.net:
 
 This looks pretty interesting:
 74G series PO74G74
 
 http://www.ebay.com/itm/330551715157?_trksid=p2060778.
 m1438.l2649ssPageName=STRK%3AMEBIDX%3AIT#ht_411wt_664
 
 600+ MHz cmos 3.5 volt
 
 Tom
 
 
 - Original Message - From: S. Jackson via time-nuts 
 time-nuts@febo.com
 To: kc0...@gmail.com; time-nuts@febo.com
 Sent: Saturday, October 18, 2014 5:40 PM
 Subject: Re: [time-nuts] LTE-Lite module
 
 
 
 Dave, et.al.,
 
 upon popular request I put together a PDF of my email describing how I
 generated a low-phase-noise 10MHz output from the CMOS 20MHz output of the
 LTE-Lite GPSDO. Here it is.
 
 No guarantees whatsoever guys, and it does take good equipment, a very
 steady hand, and a lot of experience to put this together and make it work
 properly.
 
 This design can work up to 145MHz according to the 74LVX74 datasheet if
 powered at 3.3V.
 
 bye,
 Said
 
 
 In a message dated 10/18/2014 14:09:54 Pacific Daylight Time,
 kc0...@gmail.com writes:
 
 Hi,  Said.
 
 I would be interested in having a copy of your app-note, if  that is
 possible. I'd like to purchase one of the GPSDOs, but will need to  wait
 for amonth or so.
 
 Thanks.
 
 Cheers,
 DaveD
 
 On  10/18/2014 12:19 PM, S. Jackson via time-nuts wrote:
 
 Hi  guys,
 
 lots of questions, let me try to answer  some of these. Bob, David, et.
 
 al,
 
 thanks for answering some of these  already!
 
 Dave, as Bob said it depends on your  application -- and your time
 
 frame.
 
 Also, please check the FAQ for an  answer on the external TCXO
 
 requirement,
 
 specifically item 35. in the  FAQ on the Ebay website for the product.
 
 Jim, I  ended up doing the appnote in email format, and sending out a
 description, schematics, PN plot, and photos yesterday, please check
 
 your
 
 emails. I won't do a formal appnote, sorry no time.. I hope the
 
 description of
 
 what I wired-up yesterday is good enough for folks to  try the same.
 
 Ernie, as mentioned here the price  is $185 plus shipping on Ebay for the
 entire kit. Shipping is  calculated by Ebay, and should be a flat-rate
 
 of $10
 
 in the  continental US
 
 Hal, MY BAD!! I should have known  better and super-imposed both the
 original 20MHz and 10MHz plots on  the same plot. I will do so shortly.
 
 On the
 
 table in the plot: the  TimePod tries to determine spurs, and display
 
 them  on
 
 the upper  right hand of the plot in a table, and with the phase noise
 
 being
 
 as  clean as it is I guess the TimePod software could only find two
 spurs,
 one at  0.8 and one at 0.9Hz offset from carrier, which was not even
 
 shown in
 
 that plot  since it starts at 1Hz.
 
 Thanks so much for your feedback, lively discussion, and good  questions
 guys.
 
 I hope that answers all  questions,
 bye,
 Said
 
 
 
 
 
 
 
 
 
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/
 mailman/listinfo/time-nuts
 and follow the instructions there.
 
 
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/
 mailman/listinfo/time-nuts
 and follow the instructions there.
 
 
 
 
 -- 
 
 Please  avoid sending  me  Word  or  PowerPoint  attachments.
 See  http://www.gnu.org/philosophy/no-word-attachments.html
 PDF is an better alternative and there are always LaTeX!
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

[time-nuts] LTE-Lite module

 
Hello Jim, 
let me answer through Time Nuts as this may interest  other parties as 
well. 
Yes, using a fast flip flop to generate 10MHz out of  the 20MHz TCXO 3.0V 
CMOS output from the LTE-Lite module will preserve the phase  noise (actually 
improve it by up to 6dB due to the 20log(n/m) noise improvement)  and will 
not add any spurs if you use the clean 3.0V output from the LTE-Lite  module 
or an external clean power supply (please note the LTE-Lite TCXO RF  output 
is 3.0V due to the internal 3.3V to 3.0V Low Noise regulator feeding the  
TCXO and buffer). 
Use fast logic such as 74AC74, 74FCT74, or the like.  We do exactly that on 
our ULN-2550 boards to generate 50MHz and 25MHz out of the  100MHz, and 
using a fast CMOS divider will result in additive phase noise  that will be 
below the crystal oscillator phase noise floor. 
That will result in significantly better phase noise and  much lower spurs 
than using the synthesized 10MHz output from the board, and one  74' chip 
can generate both 10MHz and 5MHz out of the 20MHz LTE-Lite output. This  is 
exactly what we would do here if we needed a clean 10MHz from the 20MHz  
LTE-Lite board. 
I believe you can order low-noise divide-by-2  blue-top boxes from Wenzel 
already packaged-up and connectorized as  well. 
Hope that helps,
Said 
Hi Said 
I was one of those looking for 10Mhz but I just thought  again now that it 
might be just as well to divide the standard 20Mhz output by 2  using a FF. 
I think that would preserve all the desirable characteristics of the  20Mhz 
signal which I understand to just be square wave at CMOS 3.3v levels  
anyway. Is that correct? 
Thanks 
Jim
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-17 Thread Jim Sanford

I have emailed Wenzel about pricing and whether or not they will sell 
small quantities.  Will advise.


Jim
wb4...@amsat.org

On 10/17/2014 2:32 PM, S. Jackson via time-nuts wrote:
  
Hello Jim,

let me answer through Time Nuts as this may interest  other parties as
well.
Yes, using a fast flip flop to generate 10MHz out of  the 20MHz TCXO 3.0V
CMOS output from the LTE-Lite module will preserve the phase  noise (actually
improve it by up to 6dB due to the 20log(n/m) noise improvement)  and will
not add any spurs if you use the clean 3.0V output from the LTE-Lite  module
or an external clean power supply (please note the LTE-Lite TCXO RF  output
is 3.0V due to the internal 3.3V to 3.0V Low Noise regulator feeding the
TCXO and buffer).
Use fast logic such as 74AC74, 74FCT74, or the like.  We do exactly that on
our ULN-2550 boards to generate 50MHz and 25MHz out of the  100MHz, and
using a fast CMOS divider will result in additive phase noise  that will be
below the crystal oscillator phase noise floor.
That will result in significantly better phase noise and  much lower spurs
than using the synthesized 10MHz output from the board, and one  74' chip
can generate both 10MHz and 5MHz out of the 20MHz LTE-Lite output. This  is
exactly what we would do here if we needed a clean 10MHz from the 20MHz
LTE-Lite board.
I believe you can order low-noise divide-by-2  blue-top boxes from Wenzel
already packaged-up and connectorized as  well.
Hope that helps,
Said
Hi Said
I was one of those looking for 10Mhz but I just thought  again now that it
might be just as well to divide the standard 20Mhz output by 2  using a FF.
I think that would preserve all the desirable characteristics of the  20Mhz
signal which I understand to just be square wave at CMOS 3.3v levels
anyway. Is that correct?
Thanks
Jim
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.




---
This email is free from viruses and malware because avast! Antivirus protection 
is active.
http://www.avast.com

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Hi there,
 
I don't know how much the Wenzel units are, but if someone is not able  to, 
or willing to build one on their own then this could be a  viable 
alternative.
 
I will look into writing a short appnote describing how a low-noise  
div-by-2 can be built at home with minimal components using a surface mount '74 
 
chip and a couple of passives.
 
Lastly the 20MHz LTE-Lite boards do generate a 10MHz output of course, and  
if you feed that into a standard counter (5370B, 53132A etc etc) I  think 
the noise floor of the counter would be higher than the  noise floor of the 
synthesized 10MHz output, so you would not see any difference  between using 
the noisier synthesized output and the low-noise 10MHz TCXO  divided output..
 
Bye,
Said
 
 
In a message dated 10/17/2014 13:19:08 Pacific Daylight Time,  
gign...@gmail.com writes:

How much would we guess that Wenzel blue-top would run you?


Relative to the low cost GPSDO,  my understanding is the Wenzel  parts are 
priced appropriately to their quality.






On Fri, Oct 17, 2014 at 11:32 AM, S. Jackson via  time-nuts 
_time-nuts@febo.com_ (mailto:time-nuts@febo.com)  wrote:


Hello  Jim,
let me answer through Time Nuts as this may interest  other  parties as
well.
Yes, using a fast flip flop to generate 10MHz out  of  the 20MHz TCXO 3.0V
CMOS output from the LTE-Lite module will  preserve the phase  noise 
(actually
improve it by up to 6dB due to  the 20log(n/m) noise improvement)  and will
not add any spurs if you  use the clean 3.0V output from the LTE-Lite  
module
or an external  clean power supply (please note the LTE-Lite TCXO RF  output
is 3.0V  due to the internal 3.3V to 3.0V Low Noise regulator feeding the
TCXO and  buffer).
Use fast logic such as 74AC74, 74FCT74, or the like.  We do  exactly that on
our ULN-2550 boards to generate 50MHz and 25MHz out of  the  100MHz, and
using a fast CMOS divider will result in additive  phase noise  that will be
below the crystal oscillator phase noise  floor.
That will result in significantly better phase noise and   much lower spurs
than using the synthesized 10MHz output from the board,  and one  74' chip
can generate both 10MHz and 5MHz out of the 20MHz  LTE-Lite output. This  is
exactly what we would do here if we needed  a clean 10MHz from the 20MHz
LTE-Lite board.
I believe you can order  low-noise divide-by-2  blue-top boxes from Wenzel
already  packaged-up and connectorized as  well.
Hope that  helps,
Said
Hi Said
I was one of those looking for 10Mhz but I just  thought  again now that it
might be just as well to divide the  standard 20Mhz output by 2  using a FF.
I think that would preserve  all the desirable characteristics of the  20Mhz
signal which I  understand to just be square wave at CMOS 3.3v levels
anyway. Is that  correct?
Thanks
Jim
___
time-nuts  mailing list -- _time-nuts@febo.com_ (mailto:time-nuts@febo.com) 
To unsubscribe,  go to 
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and  follow the instructions  there.





___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-17 Thread Neil Schroeder

How much would we guess that Wenzel blue-top would run you?

Relative to the low cost GPSDO,  my understanding is the Wenzel parts are
priced appropriately to their quality.



On Fri, Oct 17, 2014 at 11:32 AM, S. Jackson via time-nuts 
time-nuts@febo.com wrote:


 Hello Jim,
 let me answer through Time Nuts as this may interest  other parties as
 well.
 Yes, using a fast flip flop to generate 10MHz out of  the 20MHz TCXO 3.0V
 CMOS output from the LTE-Lite module will preserve the phase  noise
 (actually
 improve it by up to 6dB due to the 20log(n/m) noise improvement)  and will
 not add any spurs if you use the clean 3.0V output from the LTE-Lite
 module
 or an external clean power supply (please note the LTE-Lite TCXO RF  output
 is 3.0V due to the internal 3.3V to 3.0V Low Noise regulator feeding the
 TCXO and buffer).
 Use fast logic such as 74AC74, 74FCT74, or the like.  We do exactly that on
 our ULN-2550 boards to generate 50MHz and 25MHz out of the  100MHz, and
 using a fast CMOS divider will result in additive phase noise  that will be
 below the crystal oscillator phase noise floor.
 That will result in significantly better phase noise and  much lower spurs
 than using the synthesized 10MHz output from the board, and one  74' chip
 can generate both 10MHz and 5MHz out of the 20MHz LTE-Lite output. This  is
 exactly what we would do here if we needed a clean 10MHz from the 20MHz
 LTE-Lite board.
 I believe you can order low-noise divide-by-2  blue-top boxes from Wenzel
 already packaged-up and connectorized as  well.
 Hope that helps,
 Said
 Hi Said
 I was one of those looking for 10Mhz but I just thought  again now that it
 might be just as well to divide the standard 20Mhz output by 2  using a FF.
 I think that would preserve all the desirable characteristics of the  20Mhz
 signal which I understand to just be square wave at CMOS 3.3v levels
 anyway. Is that correct?
 Thanks
 Jim
 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

And lastly the entire setup as tested:
 
 
In a message dated 10/17/2014 11:32:49 Pacific Daylight Time,  
saidj...@aol.com writes:

 
Hello Jim, 
let me answer through Time Nuts as this may interest  other parties as 
well. 
Yes, using a fast flip flop to generate 10MHz out  of the 20MHz TCXO 3.0V 
CMOS output from the LTE-Lite module will preserve the  phase noise (actually 
improve it by up to 6dB due to the 20log(n/m) noise  improvement) and will 
not add any spurs if you use the clean 3.0V output from  the LTE-Lite module 
or an external clean power supply (please note the  LTE-Lite TCXO RF output 
is 3.0V due to the internal 3.3V to 3.0V Low Noise  regulator feeding the 
TCXO and buffer). 
Use fast logic such as 74AC74, 74FCT74, or the  like. We do exactly that on 
our ULN-2550 boards to generate 50MHz and 25MHz  out of the 100MHz, and 
using a fast CMOS divider will result in additive  phase noise that will be 
below the crystal oscillator phase noise  floor. 
That will result in significantly better phase noise  and much lower spurs 
than using the synthesized 10MHz output from the board,  and one 74' chip 
can generate both 10MHz and 5MHz out of the 20MHz LTE-Lite  output. This is 
exactly what we would do here if we needed a clean 10MHz from  the 20MHz 
LTE-Lite board. 
I believe you can order low-noise divide-by-2  blue-top boxes from Wenzel 
already packaged-up and connectorized as  well. 
Hope that helps,
Said 
Hi Said 
I was one of those looking for 10Mhz but I just thought  again now that it 
might be just as well to divide the standard 20Mhz output by  2 using a FF. 
I think that would preserve all the desirable characteristics of  the 20Mhz 
signal which I understand to just be square wave at CMOS 3.3v  levels 
anyway. Is that correct? 
Thanks 
Jim

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Jim,
 
Here is the resulting 10MHz phase noise plot from the 20MHz TCXO  output:
 
 
In a message dated 10/17/2014 11:32:49 Pacific Daylight Time,  
saidj...@aol.com writes:

 
Hello Jim, 
let me answer through Time Nuts as this may interest  other parties as 
well. 
Yes, using a fast flip flop to generate 10MHz out  of the 20MHz TCXO 3.0V 
CMOS output from the LTE-Lite module will preserve the  phase noise (actually 
improve it by up to 6dB due to the 20log(n/m) noise  improvement) and will 
not add any spurs if you use the clean 3.0V output from  the LTE-Lite module 
or an external clean power supply (please note the  LTE-Lite TCXO RF output 
is 3.0V due to the internal 3.3V to 3.0V Low Noise  regulator feeding the 
TCXO and buffer). 
Use fast logic such as 74AC74, 74FCT74, or the  like. We do exactly that on 
our ULN-2550 boards to generate 50MHz and 25MHz  out of the 100MHz, and 
using a fast CMOS divider will result in additive  phase noise that will be 
below the crystal oscillator phase noise  floor. 
That will result in significantly better phase noise  and much lower spurs 
than using the synthesized 10MHz output from the board,  and one 74' chip 
can generate both 10MHz and 5MHz out of the 20MHz LTE-Lite  output. This is 
exactly what we would do here if we needed a clean 10MHz from  the 20MHz 
LTE-Lite board. 
I believe you can order low-noise divide-by-2  blue-top boxes from Wenzel 
already packaged-up and connectorized as  well. 
Hope that helps,
Said 
Hi Said 
I was one of those looking for 10Mhz but I just thought  again now that it 
might be just as well to divide the standard 20Mhz output by  2 using a FF. 
I think that would preserve all the desirable characteristics of  the 20Mhz 
signal which I understand to just be square wave at CMOS 3.3v  levels 
anyway. Is that correct? 
Thanks 
Jim



LTE_10MHz_divide-by-2_PN.png
Description: Binary data
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Jim, et. al.,
 
I spent some time today and put together a Divide-by-2 circuit. Attached  
are the schematics, I will send some photos in additional mails so we don't  
overload the mail system.
 
Some comments:
 
* I grab the 3.0V from capacitor C6 on the eval board. That is the  
low-noise filtered analog supply. By loading it with the FF, that voltage goes  
down to 2.86V.. Using the digital 3.3V supply resulted in excessive spurs.
 
* I used only two additional components: a cap and a series resistor
 
* The IC I used was an old Fairchild 74LVX74 SO-14 chip I had laying  around
 
* Notice the nice improvement in phase noise, and the absence of any  
measurable spurs
 
* Notice the nice 6dB phase noise improvement compared to using the direct  
outptut, even the floor improved to close to my reference noise floor, so 
theory  meets practice
 
* I spent less than 45 minutes building this on a small copper-clad board,  
using the ground of the board as much as possible
 
* The output power of the 74LVC74 driving the 50 Ohms input impedance of  
the analyzer is pretty low, less than 7dBm, so a nice buffer would help
 
* Notice how I set the Q output of the unused FF to 0V, and then connect  
that pin to ground to use it as an additional ground pin
 
* While I wired up the 3.0V power to the eval board, I did not even bother  
wiring up the ground. I simply used the coax cables as DC ground return
 
* The LTE-Lite board was powered from a Thinkpad PC via USB cable, and  
disciplining to GPS so I did not even use an external low-noise isolated 5V lab 
 supply or anything like that, just the noise PC's USB port.
 
Bye,
Said
 
 
 
In a message dated 10/17/2014 11:32:49 Pacific Daylight Time,  
saidj...@aol.com writes:

 
Hello Jim, 
let me answer through Time Nuts as this may interest  other parties as 
well. 
Yes, using a fast flip flop to generate 10MHz out  of the 20MHz TCXO 3.0V 
CMOS output from the LTE-Lite module will preserve the  phase noise (actually 
improve it by up to 6dB due to the 20log(n/m) noise  improvement) and will 
not add any spurs if you use the clean 3.0V output from  the LTE-Lite module 
or an external clean power supply (please note the  LTE-Lite TCXO RF output 
is 3.0V due to the internal 3.3V to 3.0V Low Noise  regulator feeding the 
TCXO and buffer). 
Use fast logic such as 74AC74, 74FCT74, or the  like. We do exactly that on 
our ULN-2550 boards to generate 50MHz and 25MHz  out of the 100MHz, and 
using a fast CMOS divider will result in additive  phase noise that will be 
below the crystal oscillator phase noise  floor. 
That will result in significantly better phase noise  and much lower spurs 
than using the synthesized 10MHz output from the board,  and one 74' chip 
can generate both 10MHz and 5MHz out of the 20MHz LTE-Lite  output. This is 
exactly what we would do here if we needed a clean 10MHz from  the 20MHz 
LTE-Lite board. 
I believe you can order low-noise divide-by-2  blue-top boxes from Wenzel 
already packaged-up and connectorized as  well. 
Hope that helps,
Said 
Hi Said 
I was one of those looking for 10Mhz but I just thought  again now that it 
might be just as well to divide the standard 20Mhz output by  2 using a FF. 
I think that would preserve all the desirable characteristics of  the 20Mhz 
signal which I understand to just be square wave at CMOS 3.3v  levels 
anyway. Is that correct? 
Thanks 
Jim

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

Some photos of the divider module I built:
 
 
In a message dated 10/17/2014 11:32:49 Pacific Daylight Time,  
saidj...@aol.com writes:

 
Hello Jim, 
let me answer through Time Nuts as this may interest  other parties as 
well. 
Yes, using a fast flip flop to generate 10MHz out  of the 20MHz TCXO 3.0V 
CMOS output from the LTE-Lite module will preserve the  phase noise (actually 
improve it by up to 6dB due to the 20log(n/m) noise  improvement) and will 
not add any spurs if you use the clean 3.0V output from  the LTE-Lite module 
or an external clean power supply (please note the  LTE-Lite TCXO RF output 
is 3.0V due to the internal 3.3V to 3.0V Low Noise  regulator feeding the 
TCXO and buffer). 
Use fast logic such as 74AC74, 74FCT74, or the  like. We do exactly that on 
our ULN-2550 boards to generate 50MHz and 25MHz  out of the 100MHz, and 
using a fast CMOS divider will result in additive  phase noise that will be 
below the crystal oscillator phase noise  floor. 
That will result in significantly better phase noise  and much lower spurs 
than using the synthesized 10MHz output from the board,  and one 74' chip 
can generate both 10MHz and 5MHz out of the 20MHz LTE-Lite  output. This is 
exactly what we would do here if we needed a clean 10MHz from  the 20MHz 
LTE-Lite board. 
I believe you can order low-noise divide-by-2  blue-top boxes from Wenzel 
already packaged-up and connectorized as  well. 
Hope that helps,
Said 
Hi Said 
I was one of those looking for 10Mhz but I just thought  again now that it 
might be just as well to divide the standard 20Mhz output by  2 using a FF. 
I think that would preserve all the desirable characteristics of  the 20Mhz 
signal which I understand to just be square wave at CMOS 3.3v  levels 
anyway. Is that correct? 
Thanks 
Jim

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module

2014-10-17 Thread John C. Westmoreland, P.E.

Said,

What tool(s) did you use to generate that data and output the graph?

Thanks,
John


On Fri, Oct 17, 2014 at 6:10 PM, S. Jackson via time-nuts 
time-nuts@febo.com wrote:

 Jim,

 Here is the resulting 10MHz phase noise plot from the 20MHz TCXO  output:


 In a message dated 10/17/2014 11:32:49 Pacific Daylight Time,
 saidj...@aol.com writes:


 Hello Jim,
 let me answer through Time Nuts as this may interest  other parties as
 well.
 Yes, using a fast flip flop to generate 10MHz out  of the 20MHz TCXO 3.0V
 CMOS output from the LTE-Lite module will preserve the  phase noise
 (actually
 improve it by up to 6dB due to the 20log(n/m) noise  improvement) and will
 not add any spurs if you use the clean 3.0V output from  the LTE-Lite
 module
 or an external clean power supply (please note the  LTE-Lite TCXO RF output
 is 3.0V due to the internal 3.3V to 3.0V Low Noise  regulator feeding the
 TCXO and buffer).
 Use fast logic such as 74AC74, 74FCT74, or the  like. We do exactly that on
 our ULN-2550 boards to generate 50MHz and 25MHz  out of the 100MHz, and
 using a fast CMOS divider will result in additive  phase noise that will be
 below the crystal oscillator phase noise  floor.
 That will result in significantly better phase noise  and much lower spurs
 than using the synthesized 10MHz output from the board,  and one 74' chip
 can generate both 10MHz and 5MHz out of the 20MHz LTE-Lite  output. This is
 exactly what we would do here if we needed a clean 10MHz from  the 20MHz
 LTE-Lite board.
 I believe you can order low-noise divide-by-2  blue-top boxes from Wenzel
 already packaged-up and connectorized as  well.
 Hope that helps,
 Said
 Hi Said
 I was one of those looking for 10Mhz but I just thought  again now that it
 might be just as well to divide the standard 20Mhz output by  2 using a FF.
 I think that would preserve all the desirable characteristics of  the 20Mhz
 signal which I understand to just be square wave at CMOS 3.3v  levels
 anyway. Is that correct?
 Thanks
 Jim


 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] LTE-Lite module