Re: [time-nuts] time-nuts Digest, Vol 189, Issue 11

[Dave B via time-nuts]

Hi Skip.

Does the Austron even recognise the *IDN? query that Ni-Max uses to
identify instruments?  Information on those is "thin" on the web.

Is your ENET-GPIB able to work in analyser mode, so you can see exactly
what's happening on the bus as the PC scans for devices?

Check the cables.  If I had a penny for every bus issue that was caused
by a bad cable, I could have retired by now.

Try running "NI I/O Trace" (what used to be known as NI-Spy) to see
what's going on, or not.  Often a good first hit tool to use.

If not, can you beg-borrow or otherwise find for temporary use, a NI
GPIB-USB-HS+ adapter?  (The + versions have the analyser needed bus data
latch enabled.)

Some other makes of GPIB PC I/O card can sometimes be used as a capable
bus protocol analyser, the early "BrainBoxes Professional 488" 8 bit ISA
PC card in particular. (In reality, a generic parallel I/O chip, some
glue logic and bus driver chips.  Everything was done in software, under
DOS!  At the cost of a dedicated PC, it made in it's day, a capable bus
analyser.)

Have you tried to manually send (using the interactive comm's tool) a
simple command or query to the Austron, and see (either) a GPIB system
error message, or any response from the Austron.

There is little on the 'web in the way of any manual I could find to
read to see what might be needed.   But it's worth remembering that
these instruments are very early GPIB devices, so probably won't work
without some effort on a bog-standard modern NI based system.

Regards.

Dave B G0WBX.


On 07/04/2020 02:55, time-nuts-requ...@lists.febo.com wrote:
> Hello time-nuts,
> I have been trying to talk to the Austron 2110 via the GPIB with
> absolutely no luck.  The controller is a NI ENET-GPIB and it talks to
> the 5370B just fine.  When the find GPIB devices button is clicked the
> Austron 2110 is nowhere to be found.
> I actually have two of the 2110 units and they both behave the same
> way.  Yes, the GPIB chips are installed in both units and the IRQ
> jumper is there.  When the serial poll is done by the controller I can
> see the DAV line wiggle in the 2110, but nothing else seems to happen
> (no interrupt or acknowledge from the 68488).
>
> If anyone has any experience with these units and GPIB any help would
> be appreciated.
>
> Thanks in advance.
> Skip Withrow

-- 
Created on and sent from a Unix like PC running and using free and open source 
software:


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Re: [time-nuts] PRS-10 PPS output

[Mike Ingle]

Hi all,

Thank you for your feedback.  I found the schematics for the PRS-10 online,
and the output is 5V HCMOS.

signal :

locked -->  hc08 inhc08 out  -->  hc14 in   hc14 out --> 4x 240 ohm
resistors -> output pin
PPS-->  hc08 in

Which brings me to my next question.  I have been running this used PRS-10
FW version 3.21 with apparently (from lady heather) 126000 hours lifetime.
Since Friday when it came in the mail.  It has the bench heat sinks and the
accessory output board.  It is being disciplined by a blox5T PPS signal.
Occasionally the PPS is missing from the PRS-10 (1 in 1000 or so) .  I
presume due to loss of lock, as the and gate would inhibit PPS when lock is
zero.

First some over-all results, then some background on my testing methodology.

The PRS-10 seems to lock to PPS-in such that the PRS-10 PPS out is 1.84us
after PPS in.  The +1.84us happens to be where the time tag (TT) goes to
zero.  I suspect that something might be wrong with the Time Tag setup.
The unit steers itself until the TT=0ns, at which point the TT no longer
returns data.  The PPS out from this point seems to wander by about 60ns or
so (delay from GPS PPS in to PPS out).

Why do I think that I am missing PPS from the PRS-10?

Test 1.

GPS PPS -> scope ch2 (1M input on BNC T) -> PRS-10 PPS in
PRS-10 PPS out -> scope ch4

scope setup to trigger on ch2 PPS in and look 1.84us (200 ns/div) later at
the PRS-10 PPS out.  On infinite persistence, one clearly sees that some
PPS out times  remain at ground.

OK so is the problem that the GPS had outliers of more than +/- 1.2us (the
scope display at 200ns/div), or that the PRS-10 did not create a PPS?

Test 2.

Trigger on PRS-10 PPS-out and set up the scope delay to 1s, to observe the
next PPS after the trigger.  Set up a mask test.
This also indicates a failure.

My goal was to get a good low noise and accurate reference oscillator.  I
bought the PRS-10 for 550 euro, and probably should have just purchased a
new one, but live and learn...
It probably does not need to be GPS disciplined, but I wanted to get it
calibrated before setting it to free-running.

At this point, to get further, I probably need a time interval counter,
which I can set up using my 4ch 14 bit 500MSPS  A/D boards pulse stretching
input, which should give 5ps RMS time stamping.  Unfortunately, right now I
only have one "good" quality timebase, the PRS-10.  I do have an old
TrueTime XL-AK GPSDO, but the 10MHz out is noisy, with strong 100Hz spurs
(2X line freq in Germany), and my boards on-board 50Mhz tcxo.

The two time bases I neglected to mention, are the 10M ref out from my
Rigol DG4062, and the 10M ref out from my Siglent SSA 3021X.  I cannot
comment on their respective quality.

Possible test config 1
prs-10 10MHz -> ref in -> LMX2581 (creates 500MHz sample clk for AD9684 14
bit 500MSPS A/D)
PRS-10 pps out -> pulse stretcher ->  ch0 500MSPS A/D
ublox pps out -> ch1 500MSPS  ( does not require pulse stretcher, as the
leading edge is 48ns, and should interpolate to sub 50ps easily)

possible test config 2
50MHz tcxo -> LMX2581 (creates 500MHz sample clk for AD9684 14 bit 500MSPS
A/D)
PRS-10 pps out -> pulse stretcher ->  ch0 500MSPS A/D
ublox pps out -> ch1 500MSPS  ( does not require pulse stretcher, as the
leading edge is 48ns, and should interpolate to sub 50ps easily)
PRS-10 10MHz -> ch2 500MSPS

I think that test config 2 is probably the best until I can get a good free
running 10MHz reference.
With the shown setup I can store the arrival time/ rising edge zero
crossing of all of the inputs to a file for analysis.

Any further suggestions on test setup?

--mike




[image: pps_fail.png]



On Sun, Apr 5, 2020 at 6:43 PM Joseph Gwinn  wrote:

> On Sun, 05 Apr 2020 12:00:02 -0400, time-nuts-requ...@lists.febo.com
> wrote:
> Re: time-nuts Digest, Vol 189, Issue 9
> [snip]
> > --
> >
> > Message: 2
> > Date: Sat, 4 Apr 2020 14:08:02 -0400
> > From: Bob kb8tq 
> > To: Discussion of precise time and frequency measurement
> >   
> > Subject: Re: [time-nuts] PRS-10 PPS output
> > Message-ID: <1131af5e-3444-4e48-b5d9-ecb36457d...@n1k.org>
> > Content-Type: text/plain; charset=utf-8
> >
> > Hi
> >
> > Pulling the output of a normal CMOS gate to ground through a small
> > resistor is not generally a good idea. That?s what an attenuator or far
> > end termination of the coax is doing. It?s not specifically outlawed in
> the
> > spec, but it's still not what they are designed to do. Also the output
> level
> > is going to be pretty wimpy run through an attenuator.
> >
> > One way to 'fix' the problem is with a 50 ohm series resistor at the
> source
> > end. That only works to the degree that the output impedance of the gate
> > is very low when in saturation. How true this is?. that depends.
>
> Well, the coax 1PPS outputs I've had to deal with are all claim in
> their datasheets to be able to drive a 50-ohm load, so I didn't worry
> abo

Re: [time-nuts] PRS-10 PPS output

[Bob kb8tq]

Hi

Backing up a little bit …. the PPS in on these telecom Rb’s is designed to 
easily get the part set on frequency. It’s not designed for a GPSDO 
application. 
What you are seeing is consistent with that “application target”. 

Bob

> On Apr 7, 2020, at 6:32 AM, Mike Ingle  wrote:
> 
> Hi all,
> 
> Thank you for your feedback.  I found the schematics for the PRS-10 online,
> and the output is 5V HCMOS.
> 
> signal :
> 
> locked -->  hc08 inhc08 out  -->  hc14 in   hc14 out --> 4x 240 ohm
> resistors -> output pin
> PPS-->  hc08 in
> 
> Which brings me to my next question.  I have been running this used PRS-10
> FW version 3.21 with apparently (from lady heather) 126000 hours lifetime.
> Since Friday when it came in the mail.  It has the bench heat sinks and the
> accessory output board.  It is being disciplined by a blox5T PPS signal.
> Occasionally the PPS is missing from the PRS-10 (1 in 1000 or so) .  I
> presume due to loss of lock, as the and gate would inhibit PPS when lock is
> zero.
> 
> First some over-all results, then some background on my testing methodology.
> 
> The PRS-10 seems to lock to PPS-in such that the PRS-10 PPS out is 1.84us
> after PPS in.  The +1.84us happens to be where the time tag (TT) goes to
> zero.  I suspect that something might be wrong with the Time Tag setup.
> The unit steers itself until the TT=0ns, at which point the TT no longer
> returns data.  The PPS out from this point seems to wander by about 60ns or
> so (delay from GPS PPS in to PPS out).
> 
> Why do I think that I am missing PPS from the PRS-10?
> 
> Test 1.
> 
> GPS PPS -> scope ch2 (1M input on BNC T) -> PRS-10 PPS in
> PRS-10 PPS out -> scope ch4
> 
> scope setup to trigger on ch2 PPS in and look 1.84us (200 ns/div) later at
> the PRS-10 PPS out.  On infinite persistence, one clearly sees that some
> PPS out times  remain at ground.
> 
> OK so is the problem that the GPS had outliers of more than +/- 1.2us (the
> scope display at 200ns/div), or that the PRS-10 did not create a PPS?
> 
> Test 2.
> 
> Trigger on PRS-10 PPS-out and set up the scope delay to 1s, to observe the
> next PPS after the trigger.  Set up a mask test.
> This also indicates a failure.
> 
> My goal was to get a good low noise and accurate reference oscillator.  I
> bought the PRS-10 for 550 euro, and probably should have just purchased a
> new one, but live and learn...
> It probably does not need to be GPS disciplined, but I wanted to get it
> calibrated before setting it to free-running.
> 
> At this point, to get further, I probably need a time interval counter,
> which I can set up using my 4ch 14 bit 500MSPS  A/D boards pulse stretching
> input, which should give 5ps RMS time stamping.  Unfortunately, right now I
> only have one "good" quality timebase, the PRS-10.  I do have an old
> TrueTime XL-AK GPSDO, but the 10MHz out is noisy, with strong 100Hz spurs
> (2X line freq in Germany), and my boards on-board 50Mhz tcxo.
> 
> The two time bases I neglected to mention, are the 10M ref out from my
> Rigol DG4062, and the 10M ref out from my Siglent SSA 3021X.  I cannot
> comment on their respective quality.
> 
> Possible test config 1
> prs-10 10MHz -> ref in -> LMX2581 (creates 500MHz sample clk for AD9684 14
> bit 500MSPS A/D)
> PRS-10 pps out -> pulse stretcher ->  ch0 500MSPS A/D
> ublox pps out -> ch1 500MSPS  ( does not require pulse stretcher, as the
> leading edge is 48ns, and should interpolate to sub 50ps easily)
> 
> possible test config 2
> 50MHz tcxo -> LMX2581 (creates 500MHz sample clk for AD9684 14 bit 500MSPS
> A/D)
> PRS-10 pps out -> pulse stretcher ->  ch0 500MSPS A/D
> ublox pps out -> ch1 500MSPS  ( does not require pulse stretcher, as the
> leading edge is 48ns, and should interpolate to sub 50ps easily)
> PRS-10 10MHz -> ch2 500MSPS
> 
> I think that test config 2 is probably the best until I can get a good free
> running 10MHz reference.
> With the shown setup I can store the arrival time/ rising edge zero
> crossing of all of the inputs to a file for analysis.
> 
> Any further suggestions on test setup?
> 
> --mike
> 
> 
> 
> 
> [image: pps_fail.png]
> 
> 
> 
> On Sun, Apr 5, 2020 at 6:43 PM Joseph Gwinn  wrote:
> 
>> On Sun, 05 Apr 2020 12:00:02 -0400, time-nuts-requ...@lists.febo.com
>> wrote:
>> Re: time-nuts Digest, Vol 189, Issue 9
>> [snip]
>>> --
>>> 
>>> Message: 2
>>> Date: Sat, 4 Apr 2020 14:08:02 -0400
>>> From: Bob kb8tq 
>>> To: Discussion of precise time and frequency measurement
>>>  
>>> Subject: Re: [time-nuts] PRS-10 PPS output
>>> Message-ID: <1131af5e-3444-4e48-b5d9-ecb36457d...@n1k.org>
>>> Content-Type: text/plain; charset=utf-8
>>> 
>>> Hi
>>> 
>>> Pulling the output of a normal CMOS gate to ground through a small
>>> resistor is not generally a good idea. That?s what an attenuator or far
>>> end termination of the coax is doing. It?s not specifically outlawed in
>> the
>>> spec, but it's still not wh

Re: [time-nuts] PRS-10 PPS output

[Mike Ingle]

Hi Bob,

If I am understanding you correctly, it is normal operation that the time
tagging stops working, and that the PPS out should not phase lock to the
PPS-in?  It is perfectly fine in my application that the PPS out has a
fixed non zero offet to the average GPS PPS signal (obviously any
individual GPS PPS signal has an fairly large uncertainty in the 10s of
ns).  I had hoped that the unit would lock to the GPS  and act as a jitter
cleaner for testing our IRIG time stamping ADC boards.  I am new to the
time-nuts group, but have become interested, since creating our IRIG time
stamp circuit.  It certainly seems like a never needing rabbit hole of
needing a better reference source to be able to test the equipment one is
making.  For example on our IRIG time stamp system I measure 14ps
uncertainty using the XL-AK as a 10MHz reference, and measuring a fixed
cable length.  But our customer gets 5ps using a better reference.  I
wanted to explore the precision of the IRIG time stamp system, and am
trying to upgrade my lab as inexpensively as possible to find the limits.

Anyway, everyone's feedback is appreciated.

--mike

On Tue, Apr 7, 2020 at 2:53 PM Bob kb8tq  wrote:

> Hi
>
> Backing up a little bit …. the PPS in on these telecom Rb’s is designed to
> easily get the part set on frequency. It’s not designed for a GPSDO
> application.
> What you are seeing is consistent with that “application target”.
>
> Bob
>
> > On Apr 7, 2020, at 6:32 AM, Mike Ingle  wrote:
> >
> > Hi all,
> >
> > Thank you for your feedback.  I found the schematics for the PRS-10
> online,
> > and the output is 5V HCMOS.
> >
> > signal :
> >
> > locked -->  hc08 inhc08 out  -->  hc14 in   hc14 out --> 4x 240 ohm
> > resistors -> output pin
> > PPS-->  hc08 in
> >
> > Which brings me to my next question.  I have been running this used
> PRS-10
> > FW version 3.21 with apparently (from lady heather) 126000 hours
> lifetime.
> > Since Friday when it came in the mail.  It has the bench heat sinks and
> the
> > accessory output board.  It is being disciplined by a blox5T PPS signal.
> > Occasionally the PPS is missing from the PRS-10 (1 in 1000 or so) .  I
> > presume due to loss of lock, as the and gate would inhibit PPS when lock
> is
> > zero.
> >
> > First some over-all results, then some background on my testing
> methodology.
> >
> > The PRS-10 seems to lock to PPS-in such that the PRS-10 PPS out is 1.84us
> > after PPS in.  The +1.84us happens to be where the time tag (TT) goes to
> > zero.  I suspect that something might be wrong with the Time Tag setup.
> > The unit steers itself until the TT=0ns, at which point the TT no longer
> > returns data.  The PPS out from this point seems to wander by about 60ns
> or
> > so (delay from GPS PPS in to PPS out).
> >
> > Why do I think that I am missing PPS from the PRS-10?
> >
> > Test 1.
> >
> > GPS PPS -> scope ch2 (1M input on BNC T) -> PRS-10 PPS in
> > PRS-10 PPS out -> scope ch4
> >
> > scope setup to trigger on ch2 PPS in and look 1.84us (200 ns/div) later
> at
> > the PRS-10 PPS out.  On infinite persistence, one clearly sees that some
> > PPS out times  remain at ground.
> >
> > OK so is the problem that the GPS had outliers of more than +/- 1.2us
> (the
> > scope display at 200ns/div), or that the PRS-10 did not create a PPS?
> >
> > Test 2.
> >
> > Trigger on PRS-10 PPS-out and set up the scope delay to 1s, to observe
> the
> > next PPS after the trigger.  Set up a mask test.
> > This also indicates a failure.
> >
> > My goal was to get a good low noise and accurate reference oscillator.  I
> > bought the PRS-10 for 550 euro, and probably should have just purchased a
> > new one, but live and learn...
> > It probably does not need to be GPS disciplined, but I wanted to get it
> > calibrated before setting it to free-running.
> >
> > At this point, to get further, I probably need a time interval counter,
> > which I can set up using my 4ch 14 bit 500MSPS  A/D boards pulse
> stretching
> > input, which should give 5ps RMS time stamping.  Unfortunately, right
> now I
> > only have one "good" quality timebase, the PRS-10.  I do have an old
> > TrueTime XL-AK GPSDO, but the 10MHz out is noisy, with strong 100Hz spurs
> > (2X line freq in Germany), and my boards on-board 50Mhz tcxo.
> >
> > The two time bases I neglected to mention, are the 10M ref out from my
> > Rigol DG4062, and the 10M ref out from my Siglent SSA 3021X.  I cannot
> > comment on their respective quality.
> >
> > Possible test config 1
> > prs-10 10MHz -> ref in -> LMX2581 (creates 500MHz sample clk for AD9684
> 14
> > bit 500MSPS A/D)
> > PRS-10 pps out -> pulse stretcher ->  ch0 500MSPS A/D
> > ublox pps out -> ch1 500MSPS  ( does not require pulse stretcher, as the
> > leading edge is 48ns, and should interpolate to sub 50ps easily)
> >
> > possible test config 2
> > 50MHz tcxo -> LMX2581 (creates 500MHz sample clk for AD9684 14 bit
> 500MSPS
> > A/D)
> > PRS-10 pps out -> pulse stretcher ->  ch0 500MSPS A/D

Re: [time-nuts] PRS-10 PPS output

[Bob kb8tq]

Hi

The main point is that these Rb’s (not just the PRS-10) are not really
set up for what you are trying to do. A proper GPSDO will do a much
better job than something like this. ( GPS into PRS-10  != GPSDO ). 

There are a number of sub-variants of the PRS-10 (and the other telecom
Rb’s) so knowing exactly what this or that example will or will not do is 
tough.  Even firmware versions are not perfect indicators since there are
hardware differences as well as firmware …..

==

Assuming the 5 ps is at the ~ 2 seconds or less level, that’s about 5x10^-12. 
The spec on the PRS-10 (just sitting there) is significantly worse than this 
(parts
in 10^-11) . Playing with a disciplining input that is *much* worse than that 
level 
will only degrade things further. 

https://www.thinksrs.com/downloads/pdfs/catalog/FS740c.pdf 


Page 2 has a pretty good graph showing (green line) what the PRS-10 does
close in. The units are ADEV so they may or may not map directly to your
“5 ps” number. 

Bob

> On Apr 7, 2020, at 9:24 AM, Mike Ingle  wrote:
> 
> Hi Bob,
> 
> If I am understanding you correctly, it is normal operation that the time
> tagging stops working, and that the PPS out should not phase lock to the
> PPS-in?  It is perfectly fine in my application that the PPS out has a
> fixed non zero offet to the average GPS PPS signal (obviously any
> individual GPS PPS signal has an fairly large uncertainty in the 10s of
> ns).  I had hoped that the unit would lock to the GPS  and act as a jitter
> cleaner for testing our IRIG time stamping ADC boards.  I am new to the
> time-nuts group, but have become interested, since creating our IRIG time
> stamp circuit.  It certainly seems like a never needing rabbit hole of
> needing a better reference source to be able to test the equipment one is
> making.  For example on our IRIG time stamp system I measure 14ps
> uncertainty using the XL-AK as a 10MHz reference, and measuring a fixed
> cable length.  But our customer gets 5ps using a better reference.  I
> wanted to explore the precision of the IRIG time stamp system, and am
> trying to upgrade my lab as inexpensively as possible to find the limits.
> 
> Anyway, everyone's feedback is appreciated.
> 
> --mike
> 
> On Tue, Apr 7, 2020 at 2:53 PM Bob kb8tq  wrote:
> 
>> Hi
>> 
>> Backing up a little bit …. the PPS in on these telecom Rb’s is designed to
>> easily get the part set on frequency. It’s not designed for a GPSDO
>> application.
>> What you are seeing is consistent with that “application target”.
>> 
>> Bob
>> 
>>> On Apr 7, 2020, at 6:32 AM, Mike Ingle  wrote:
>>> 
>>> Hi all,
>>> 
>>> Thank you for your feedback.  I found the schematics for the PRS-10
>> online,
>>> and the output is 5V HCMOS.
>>> 
>>> signal :
>>> 
>>> locked -->  hc08 inhc08 out  -->  hc14 in   hc14 out --> 4x 240 ohm
>>> resistors -> output pin
>>> PPS-->  hc08 in
>>> 
>>> Which brings me to my next question.  I have been running this used
>> PRS-10
>>> FW version 3.21 with apparently (from lady heather) 126000 hours
>> lifetime.
>>> Since Friday when it came in the mail.  It has the bench heat sinks and
>> the
>>> accessory output board.  It is being disciplined by a blox5T PPS signal.
>>> Occasionally the PPS is missing from the PRS-10 (1 in 1000 or so) .  I
>>> presume due to loss of lock, as the and gate would inhibit PPS when lock
>> is
>>> zero.
>>> 
>>> First some over-all results, then some background on my testing
>> methodology.
>>> 
>>> The PRS-10 seems to lock to PPS-in such that the PRS-10 PPS out is 1.84us
>>> after PPS in.  The +1.84us happens to be where the time tag (TT) goes to
>>> zero.  I suspect that something might be wrong with the Time Tag setup.
>>> The unit steers itself until the TT=0ns, at which point the TT no longer
>>> returns data.  The PPS out from this point seems to wander by about 60ns
>> or
>>> so (delay from GPS PPS in to PPS out).
>>> 
>>> Why do I think that I am missing PPS from the PRS-10?
>>> 
>>> Test 1.
>>> 
>>> GPS PPS -> scope ch2 (1M input on BNC T) -> PRS-10 PPS in
>>> PRS-10 PPS out -> scope ch4
>>> 
>>> scope setup to trigger on ch2 PPS in and look 1.84us (200 ns/div) later
>> at
>>> the PRS-10 PPS out.  On infinite persistence, one clearly sees that some
>>> PPS out times  remain at ground.
>>> 
>>> OK so is the problem that the GPS had outliers of more than +/- 1.2us
>> (the
>>> scope display at 200ns/div), or that the PRS-10 did not create a PPS?
>>> 
>>> Test 2.
>>> 
>>> Trigger on PRS-10 PPS-out and set up the scope delay to 1s, to observe
>> the
>>> next PPS after the trigger.  Set up a mask test.
>>> This also indicates a failure.
>>> 
>>> My goal was to get a good low noise and accurate reference oscillator.  I
>>> bought the PRS-10 for 550 euro, and probably should have just purchased a
>>> new one, but live and learn...
>>> It probably does not need to be GPS disciplined, but I wanted to get it
>>> calibrated befor

[time-nuts] Now is the time for all good dogs

[Gerhard Hoffmann]

to jump over the lazy fox.

Oh, not really.


But if you always wanted to experiment with harmonic balance,

nonlinear noise and other things that your LTspice cannot do, then

Keysight currently offers 3 month trial licenses for ADS for home office use

for free.

< 
https://www.keysight.com/de/de/cmp/promotions/innovate-anywhere.html?elq_cid=1083495&cmpid=7012L00tzyG 
    >



cheers, Gerhard.


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Re: [time-nuts] Now is the time for all good dogs

[Brent]

Saw this the other day regarding training but it looks like its only the
Pathway stuff.  I don't see anything for ADS...

Brent

On Tue, Apr 7, 2020 at 12:57 PM Gerhard Hoffmann <
g...@hoffmann-hochfrequenz.de> wrote:

> to jump over the lazy fox.
>
> Oh, not really.
>
>
> But if you always wanted to experiment with harmonic balance,
>
> nonlinear noise and other things that your LTspice cannot do, then
>
> Keysight currently offers 3 month trial licenses for ADS for home office
> use
>
> for free.
>
> <
>
> https://www.keysight.com/de/de/cmp/promotions/innovate-anywhere.html?elq_cid=1083495&cmpid=7012L00tzyG
>  >
>
>
> cheers, Gerhard.
>
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>
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Re: [time-nuts] Now is the time for all good dogs

[Gerhard Hoffmann]

Am 07.04.20 um 19:27 schrieb Brent:

Saw this the other day regarding training but it looks like its only the
Pathway stuff.  I don't see anything for ADS...


It seems they have renamed it.


< 
https://www.keysight.com/de/de/products/software/pathwave-design-software/pathwave-advanced-design-system.html 
   >


My exposure to ADS is growing old already.


Gerhard





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Re: [time-nuts] Now is the time for all good dogs

[Richard (Rick) Karlquist]

When I worked for Agilent, I had full access for "free" to
all these tools, and access to their designers, etc.
Nevertheless, the time commitment to learn these tools
is prohibitive to any engineer who is responsible for
designing the complete product, not just designing a chip.
I mainly only ever used ADS, which is a nice improvement over
LTSpice.  I never did understand what X parameters were good
for, despite hearing in house talks by its inventor.

The Keysight management has a desperate (IMHO) business plan
to reposition itself as a software company since the bottom
end of the hardware business has been taken over by cheap
offshore instruments.  I guess this is the latest salvo
in the war to defeat NI (good luck).

Speaking of what LTSpice cannot do:  I don't care about
harmonic balance, etc, I just wish it it had better data
plotting capability.  An especially egregious "feature"
is the automatic autoscaling.  Yes, you can use a workaround
where you get the scaling you want, and then save it, and
then recall it again EVERY TIME you do a run.  I really miss
ADS in this respect.

Rather than a free 3 month license, I would rather rent the
software BY THE HOUR not by the calendar.  I might be happy
to pay $50 an hour once in a while for an intense ADS
session that would increase my productivity enough to be
worth it.  But I wouldn't use ADS often enough to justify
a calendar subscription service, unless it was like a few
hundred dollars a year.

Rick N6RK

On 4/7/2020 9:56 AM, Gerhard Hoffmann wrote:

to jump over the lazy fox.

Oh, not really.


But if you always wanted to experiment with harmonic balance,

nonlinear noise and other things that your LTspice cannot do, then

Keysight currently offers 3 month trial licenses for ADS for home office 
use


for free.

< 
https://www.keysight.com/de/de/cmp/promotions/innovate-anywhere.html?elq_cid=1083495&cmpid=7012L00tzyG 
     >



cheers, Gerhard.


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[time-nuts] DIY HP 105B Service Manual

[Perry Sandeen via time-nuts]

Esteemed Members,
Several years ago I had a late model HP 105B that was configured with the HP 
10811 OCXO and was only listed in an errata document so I made my own.
I've sent it to the KO4BB website for posting.
I had misplaced my files and had thought I'd lost them in a hard drive crash.
If anyone needs a copy before it's posted, contact me off list and I'll email 
it to you.
Regards,
Perrier
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[time-nuts] Phase noise principle and measuring confusion

[Perry Sandeen via time-nuts]

Learned Gentleman,
I've read several articles on phase noise but I'm lost.
I need a *Ding-Dong* school explanation of what it is, why it's important and 
how one goes about measuring it.
 Bob wrote:
Phase measurement of my GPSDO

Thequick way to do this is with a single mixer. Take something like anold 10811 
and use the coarse tune to set it high in frequency by 5 to10 Hz.




Thenfeed it into an RPD-1 mixer and pull out the 5 to 10 Hz audio tone.That 
tone is the *difference* between the 10811 and your device undertest. 




Ifthe DUT moves 1 Hz, the audio tone changes by 1 Hz.




Ifyou measured the 10 MHz on the DUT, that 1 Hz would be a very smallshift ( 
0.1 ppm ). At 10 Hz it’s a 10% change. You have ‘amplified’ the change in 
frequency by the ratio of 10 MHz to 10 Hz ( so amillion X increase ).



*IF*you could tack that on to the ADEV plot of your 5335 ( no, it’s notthat 
simple) your 7x10^-10 at 1 second would become more 7x10^-16 at1 second.


OK, this seems to me that this is measuring frequency difference.

wrote:




Thereason its not quite that simple is that the input circuit on thecounter 
really does not handle a 10 Hz audio tone as well as ithandles a 10 MHz RF 
signal. Instead of getting 9 digits a second, youprobably will get three *good* 
digits a second and another 6 digitsof noise.

OK, then would using a 3336A synthesizer work by using the *good* 10811 or 
other 10 MHz as an external reference and provide, say, a 10 MHz + 100 Hz or 10 
MHz + 1KHz work with the 5335? (I have two). Or am I missing something (or a 
lot)?
Regards,
Perrier








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Re: [time-nuts] Phase noise principle and measuring confusion

[Bob kb8tq]

Hi

Phase is what drives an ADEV measurement ( frequency from phase ….). Phase 
noise the noise
at a specific offset from a carrier, often normalized to a 1 Hz bandwidth. 
Phase noise is a different
measure than “phase”. ( = they are not the same thing ).

Indeed a single mixer can be used as the heart of a measurement system for both 
quantities. You
do configure it differently depending on what you are after. Same basic 
hardware, different setups
to get different results. 

If you are looking at phase noise you put the mixer in quadrature lock ( just 
like the HP 3048) and 
use some sort of audio spectrum analyzer to figure out what the numbers are. 
You need a servo 
amp to keep things in lock.

If you are after phase, you offset the oscillators and get an audio tone out of 
the mixer ( a beat 
note …). The lower the tone frequency the greater the amplification ( and the 
more mixer noise
to deal with…..). For phase you need a low noise limiter to turn the audio into 
something your 
counter can deal with. 

Does it make sense to build both setups into the same box? Maybe it does. It 
depends a lot on 
just how much that mixer hits your “playing around” budget. 

Bob

> On Apr 7, 2020, at 7:42 PM, Perry Sandeen via time-nuts 
>  wrote:
> 
> Learned Gentleman,
> I've read several articles on phase noise but I'm lost.
> I need a *Ding-Dong* school explanation of what it is, why it's important and 
> how one goes about measuring it.
>  Bob wrote:
> Phase measurement of my GPSDO
> 
> Thequick way to do this is with a single mixer. Take something like anold 
> 10811 and use the coarse tune to set it high in frequency by 5 to10 Hz.
> 
> 
> 
> 
> Thenfeed it into an RPD-1 mixer and pull out the 5 to 10 Hz audio tone.That 
> tone is the *difference* between the 10811 and your device undertest. 
> 
> 
> 
> 
> Ifthe DUT moves 1 Hz, the audio tone changes by 1 Hz.
> 
> 
> 
> 
> Ifyou measured the 10 MHz on the DUT, that 1 Hz would be a very smallshift ( 
> 0.1 ppm ). At 10 Hz it’s a 10% change. You have ‘amplified’ the change in 
> frequency by the ratio of 10 MHz to 10 Hz ( so amillion X increase ).
> 
> 
> 
> *IF*you could tack that on to the ADEV plot of your 5335 ( no, it’s notthat 
> simple) your 7x10^-10 at 1 second would become more 7x10^-16 at1 second.
> 
> 
> OK, this seems to me that this is measuring frequency difference.
> 
> wrote:
> 
> 
> 
> 
> Thereason its not quite that simple is that the input circuit on thecounter 
> really does not handle a 10 Hz audio tone as well as ithandles a 10 MHz RF 
> signal. Instead of getting 9 digits a second, youprobably will get three 
> *good* digits a second and another 6 digitsof noise.
> 
> OK, then would using a 3336A synthesizer work by using the *good* 10811 or 
> other 10 MHz as an external reference and provide, say, a 10 MHz + 100 Hz or 
> 10 MHz + 1KHz work with the 5335? (I have two). Or am I missing something (or 
> a lot)?
> Regards,
> Perrier
> 
> 
> 
> 
> 
> 
> 
> 
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