ure effects on the other
> components. It is a never ending battle.
>
> BillWB6BNQ
>
>
> Bob Camp wrote:
>
>> Hi
>>
>> Ok, with a TCXO you have a temperature sensor that tries to servo the
>> crystal on to frequency. You also have a crystal with a
Hi
Different compensation approaches call for different crystal angles. Most (but
not all)
TCXO’s use AT cut crystals. What varies is the angle of cut and thus the
turnover temperatures.
If you are buying in sufficient volume, the price of a simple OCXO is well
below $10. You
need to be in t
precise?
> Nathan KK4REY
>
> Sent using CloudMagic Email
> [https://cloudmagic.com/k/d/mailapp?ct=pi&cv=7.4.15&pv=9.1&source=email_footer_2]
> On Fri, May 13, 2016 at 06:37, Bob Camp wrote:
> Hi
>
> Yes, it can be done. The performance will be poor,
Hi
Yes, it can be done. The performance will be poor, but it will work.
Bob
> On May 13, 2016, at 4:15 AM, David wrote:
>
> Has anybody tried using a thermoelectric cooler to maintain a TCVCXO
> at a constant temperature in lieu of using an OCXO?
>
> I was thinking about this after reading s
Hi
Given that a “real” TDC is a resistor and capacitor attached to a FPGA pin
(plus the ADC)
the cost of doing it better is not all that much. You can get down to a few
hundred ps without
a lot of crazy effort ( still using the MCU ADC).
Bob
> On May 13, 2016, at 3:51 AM, David wrote:
>
>
7 PM, Bob Stewart wrote:
>> Hi Bob,
>>
>> OK, I can see that. I had been wondering about how to build it out, but it
>> seems like each module should be on its own PCB for isolation. That keeps
>> the costs down, except for the numerous SMA jumpers - and the e
free of such spurs.
> Bruce
>
>
>
>On Thursday, 12 May
> 2016 3:00 PM, Bob Stewart wrote:
>
>
> Hi
> Bob,
>
> OK, I can see that.
> I had been wondering about how to build it out, but it seems
> like each module should be on its own PCB for i
such spurs.
> Bruce
>
> On Thursday, 12 May 2016 3:00 PM, Bob Stewart wrote:
>
>
> Hi Bob,
>
> OK, I can see that. I had been wondering about how to build it out, but it
> seems like each module should be on its own PCB for isolation. That keeps
> the costs do
gotten as far as the zero-crossing detectors yet, but I was
> thinking of using 125 gates.
>
> Bob
>
> On Tue, 3/29/16, Bob Camp wrote:
>
> Subject: Re: [time-nuts] high rev isolation amps
> To: "Discussion of precise ti
Hi
The same process issues that make for a “less than perfect” ADC, also
add more than a little noise into the circuit. Exactly which component(s)
are the biggest culprits … no idea. About all you can do is take data and
look at the results.
Bob
> On May 11, 2016, at 4:55 AM, David wrote:
>
Hi
I have not dug into them for several years. Back when I did, you were pushing
their limits as a couple of nanoseconds without getting into things like lots
of
averaging.
Bob
> On May 10, 2016, at 8:29 PM, David wrote:
>
> I ran a search through the time-nuts archives and found only one
Hi
Simple answer:
You are likely using an NPO cap and it’s not a big deal.
Bob
> On May 8, 2016, at 9:49 PM, David wrote:
>
> How much will dielectric absorption in the capacitor affect the
> accuracy of the result with such a high conversion rate? I am used to
> dealing with it on much l
Hi
The problem with phase pops inside a control loop is that they can come from a
lot of places. As
long as the loop is still closed they generally track out. That’s not saying
the OCXO is *not* the source,
only that there are other culprits to dig into.
Classic phase pops in an OCXO tend to b
Hi
> On May 8, 2016, at 7:08 PM, Gerhard Hoffmann wrote:
>
> Am 08.05.2016 um 21:53 schrieb Attila Kinali:
> ...
>
> Maybe I was too short. We have control over the charging current source,
> and when we switch it off, the status quo is kept. Then when the ADC is done,
> we can simply short the
Hi
SBAS is normally turned off for timing because historically it was not
optimized for timing use. The
“try it and see” approach tended to show it caused more trouble in a timing
application than it fixed.
For survey on an L1 device, it is a good idea to use it.
Bob
> On May 8, 2016, at 4:
Hi
For *survey* I would leave SBAS turned on. I would also suggest that something
like a 3 to 5 day run is needed. That’s way beyond what the
firmware can analyze. You at least need something like LH to capture and
analyze data. Since LH does not run on the uBlox, that sets you
back to serial
Hi
The way it’s normally found is in a control loop. The fact that the loop is
“dead” for
50 or 500 steps and then suddenly does something is what you quickly notice. If
you are
manually tuning a loop, it does show up.
Bob
> On May 7, 2016, at 7:26 AM, Azelio Boriani wrote:
>
> How can anyo
Hi
If you go back into the archives, there are a long series of posts about the
tuning word and tuning behavior
of the 5880. Simple answers: No the real resolution is not the same as the LSB
on the tuning word. The tuning is
closer to 1x10^12 than to 1x10^-15.
Bob
> On May 7, 2016, at 12:51
Hi
Be careful of isolation specs on some of these combiners / splitters. Often
they are deponent on the return loss
of the signal source. An OCXO that presets a 12 db return loss is doing ok. One
that is past 20 db is doing quite well.
Bob
> On May 5, 2016, at 7:00 PM, Mike Monett wrote:
>
>
od. Might as
> well pick the loudest things around, AM and TV broadcast.
>
> There are a number of SDR "kits" on the market that can sample the entire
> band or maybe 2 to 4 TV stations. TV stations might be easier because TV
> is channelized.
>
>
>
> On
Hi
At least back “a few” years ago … counting photons was a pretty good way to
generate
random numbers. It’s sort of like looking at current flow. The discrete nature
of the
process shows up if you look carefully enough.
Bob
> On May 5, 2016, at 12:55 AM, Ilia Platone wrote:
>
> Is it possi
HI
These days, there is no need to “just use one” if you are talking about AM
stations. Digitizing the entire AM band is pretty
a pretty low end SDR task these days. Storing the result will take some
storage, but noting insane;
100 Msps @ 16 bits => 200 MB / sec.
Run overnight: 30K sec
Total
Hi
Take a careful look at the phase noise requirements on a (say) 28 MHz signal
source with
a jitter of 1 ps. It’s trivial if the low end of the integration bandwidth
stops at 1 MHz. If you take
the lower limit into 1 Hz and below, it gets quite challenging. Even the math
gets a bit wonky due
Hi
A cheap GPS module and any of the nearly infinite number of sub $20 “demo
boards” would make
short work of looking at the pps, the time string out of the GPS and figuring
out when it’s the top of the
hour. I doubt it’s over 200 lines of code. I’m sure *somebody* will pop up with
an example
Hi
All of the things we yack about in terms of antenna location and timing, also
apply
to location and self survey. The gotcha is that they apply to a somewhat
greater
extent.
A timing receiver can be pretty happy with a 30 degree view to the horizon.
It’s not perfect, but it can work. For se
Hi
Ok, basic setup (most of which you have already):
Set up the counter in time interval mode. Start on channel 1 and stop on
channel 2.
Set both channels to DC coupling and whatever impedance works with your pps
signal
Manually set the trigger level to about 1/2 the zero to peak level of the
Hi
The “real” answer is to beg / borrow / obtain a geodetic receiver and let it
run for an
hour or ten at your location. Unless you are really out in the middle of
nowhere, that
will give you a very accurate position. If you don’t have any buddies who are
surveyors,
they do show up on eBay at
Hi
They changed the modulation format on WWVB back a while. It does not impact the
“wall clock” receivers
but it will not work with the carrier recovery (phase tracking) older
receivers. That’s regardless of the antenna
you happen to use. About the only solution is to run a device ahead of the
Hi
Just to toss one more possibility into the pile:
If there is an RTOS buried in the device, it’s probably got some sort of stack
management processing
going on in the background. Tasks get stacks and they are of a pre-determined
size. (Yes, that’s a lot
of guessing already). If so, you *can*
Hi
I would very much second the recommendation of Gardner’s book. It has been
the best way to get into PLL’s for a *long* time. It is unique in that the
current edition
is still as relevant today as the book was when it first came out.
Bob
> On Apr 28, 2016, at 2:00 AM, Charles Steinmetz wrot
Hi
The 5334B event is commonly called a frequency jump. There is a fairly famous
HP paper on testing for them that invokes the phrase “test to destruction” (if
I remember
correctly). They are seen in all OCXO’s if you watch enough parts long enough.
They tend to increase
in time between jumps as
AM, Attila Kinali wrote:
>
> On Mon, 25 Apr 2016 20:45:53 -0400
> Bob Camp wrote:
>
>>> To get to CMOS levels, you usually add a simple inverter, with an
>>> capacitor in front and a 1M resistor across the inverter (from input
>>> to output).
>>
>>
Hi
> On Apr 25, 2016, at 7:36 PM, Attila Kinali wrote:
>
> On Mon, 25 Apr 2016 23:34:52 +0200
> Ilia Platone wrote:
>
>> I selected this because of the CMOS output, since I didn't find any
>> Connor Winfield osc with these levels yet.
>
> To get to CMOS levels, you usually add a simple inve
….
Bob
> On Apr 24, 2016, at 12:28 AM, Richard (Rick) Karlquist
> wrote:
>
>
>
> On 4/23/2016 6:27 PM, Bob Camp wrote:
>> Hi
>>
>> The 5334 spanned the era when the 10811 was being introduced. I’ve never been
>> able to sort out exactly *what* w
Hi
The 5334 spanned the era when the 10811 was being introduced. I’ve never been
able to sort out exactly *what* was in each version as shipped and what got
swapped
around by various techs over the years. I always *thought* the 10811 was
standard for the 5334B version. There are a lot of example
Hi
Does your 5334B have a 10811 in it or some other OCXO?
Bob
> On Apr 23, 2016, at 5:04 PM, Hal Murray wrote:
>
>
> This is the result of a HP 5334B with opt 010 watching a GPSDO. It was
> unplugged for a week or two while I was rearranging things.
>
> You have to stand on your head. No
Hi
The intended purpose of MDEV was to supply a plot that looked the same as an
ADEV
plot *except* for separating flicker phase. To the extent they succeeded, you
can use
the same plot on either one. (and as long as flicker phase is not an issue). To
the extent
they failed, you are stuck.
Bob
your receiver, so you shouldn't cut the RG-174, otherwise you
> may overload the receiver's front-end.
>
> Bob
> ----
> On Fri, 4/22/16, Bob Camp wrote:
>
> Subject: Re: [time-nuts] RG6 or LMR400 for GPS Antenna
>>>
>>>>>
>>> -Ryan Stasel
>>>>>
>>>>>> On Apr 21, 2016, at 06:02 , paul
>>> swed
>>> wrote:
>>>>>>
>>>>>> With respect to sealing. Everyone
>>> has a method.
>
>>>>> scotch kote
>>>>> Layer of plastic tape
>>>>> scotch kote
>>>>> If done well the connector
>> releases just fine even after 5 or more
>>>> years. I
>>>>>
>> want to say 10. But then woodpec
Hi
Most of the data sheets on RG-6 Quad show it around 9 db per 100’. Like any of
the
“old” (RG) specs, there really is no control on who does what with a given type
of
cable. The direct burial versions seem to be a little more consistent.
Bob
> On Apr 20, 2016, at 6:48 PM, Pete Stephenson
Hi
Most of these telco Rb’s start out around 2x10^-11 at 1 second tau. Their ADEV
then drops
as square root of tau. At 100 seconds they hit 2x10^-12 and at 10,000 seconds
they (might)
hit 2x10^-13. A *good* OCXO will do 2x10^-12 at 100 seconds. An excellent part
will hold
sub 1x10^-12 out to 1
Hi
RG-6 Quad Shield should be fine as long as it’s meeting the published specs.
The advantage of LRM-400 is that you likely *know* where it came from and what
the specs are.
If you decide to split the antenna between GPSDO’s, a powered splitter is a
really good idea. Each time you split anoth
Does anyone else have comparative experience with the new SMT modules
> from Trimble? RES or ICM?
>
> Thanks,
> -Logan
>
> On Tue, Apr 19, 2016 at 4:01 AM, Bob Camp wrote:
>
>> Hi
>>
>> The two plots shown appear to be identical. If they are actually two
>
Hi
The two plots shown appear to be identical. If they are actually two different
runs, the problem repeats very closely.
If the GPS is not in position hold *and* the antenna is less than ideal -
That’s
the sort of thing you may see. Essentially it’s got two locations it “thinks”
are
correc
Hi
If our approach was to fabricate an IC totally from scratch for this or that
application,
there are a lot of things that could be done. Unfortunately, for most of us,
doing that
to wire up an output on a board … not so much.
Starting back in the 1970’s people stopped making packaged invert
Hi
LH is designed to work with Trimble (and not Symmetricom) GPSDO’s. The HP /
Symmetricom
“empire” does not have anything quite as nice as LH to support it.
There are indeed “Trimble” labeled GPSDO’s on the auction sites that are not
actually GPSDO’s
made by Trimble. They have a few parts i
Hi
You are correct in your observation that the short term stability of a TCXO
*does* impact GPSDO performance. An OCXO
(once it has warmed up and stabilized) will do better than a TCXO.
Because of the higher sensitivity of a TCXO on the EFC, there will be some
change to the firmware when goi
Hi
If the PPS is being generated by an FPGA or a MCU, inverted is as easy to
generate as
not inverted. Many decades ago an “un buffered” inverter was the speed king.
These days,
as you have noticed, the difference between inverters and bufferers is not
significant. For
non-inverting setups the
Hi
If the resistors are typical thick film SMT parts, they will begin to have
issues below
1 GHz. Thin film resistors will get you a bit higher than thick films. In both
cases board
layout to achieve 1 GHz performance is going to be a challenge.
All that said, for a 1 PPS output the waveform l
Hi
Just about any of the modern ‘125 or ‘126 buffer gates will do a pretty good
job
of generating a logic output:
https://www.fairchildsemi.com/datasheets/NC/NC7SZ125.pdf
https://www.fairchildsemi.com/datasheets/NC/NC7SZ126.pdf
http://www.nxp.com/products/discretes-and-logic/logic/quad-buffer-3
Hi
The same “Collins Limiter” stuff that goes along with DMTD’s applies to 60 Hz
power
measurement as well. There is a “magic bandwidth” that combined with a slew
rate
will give you an optimum result. The gotcha is that you need to know the noise
parameters inorder to work it out. Even back i
Hi
I had a 5360 on my bench in the 1970’s. Back then it was a pretty impressive
piece of gear. The most amazing thing I remember doing with it was converting
the output to PPM. Yes, that’s not really all that exciting these days …..
Bob
> On Apr 13, 2016, at 5:32 PM, Jeremy Nichols wrote:
>
Hi
If you *do* want to go with the fancy ADC approach, there are MCU’s that are
built specifically for
power meter applications. They have cool stuff like 24 bit ADC’s and DSP
capability. Since the
target it high volume, the cost is sub $10 …
That’s still an IF by the way. It’s still not at a
Hi
Is there a “common view” to a TV station or an FM radio station or a cell tower
or ….
Carrier phase works on terrestrial signals. If you have one with a stable
enough career and
a complex enough modulation to work out which cycle is which, it might be a
cheaper approach.
Bob
> On Apr 1
Hi
Judging by what can be seen in the eBay listing pictures: That is a mid 1990’s
design. I would
*guess* that the same i/o (baud rates, basic commands) that works with a 3801
would work with it.
Given it’s physical resemblance to a TBolt … it might talk to LH …
Fortunately the power connector
a mentioned using "LEA-M8T". I assume the T suffix
> relates to Time rather than the plain GPS. What is the difference? Apart from
> 50% higher cost.
>
>
> Cheers
> Will
> ZL1TAO
>
>
>> Sent: Sunday, April 10, 2016 at 7:00 AM
>> From: "Bob Ca
;>> filtering to take it out.
>>
>>> Bob
>>
>>>> On Apr 8, 2016, at 7:06 AM, Herbert Poetzl
> wrote:
>>>>
>>>> On Mon, Apr 04, 2016 at 06:07:54PM -0700, Alexander Pummer wrote:
>>>>> and it is relative easy t
divide it. The only settings on the module are for outputs at or below
the internal TCXO frequency.
Bob
>
> On Fri, Apr 8, 2016 at 5:13 PM, Bob Camp wrote:
>
>> Hi
>>
>> If you start from a 24 MHz TCXO (different modules use different TCXO’s):
>>
>> On an
y to make 10MHz from 8MHz with analog
>>>> frequency manipulation, which generates less jitter
>>>
>>> Could you elaborate on this a little if time permits?
>>> I'm more a 'digital person' but it sounds interesting.
>>>
>&g
Hi
> On Apr 8, 2016, at 10:35 PM, Herbert Poetzl wrote:
>
> On Fri, Apr 08, 2016 at 06:13:07PM -0400, Bob Camp wrote:
>> Hi
>
>> If you start from a 24 MHz TCXO (different modules use
>> different TCXO’s):
>
>> On an 8 MHz output, most of the time
y manipulation, which generates less jitter
>
> Could you elaborate on this a little if time permits?
> I'm more a 'digital person' but it sounds interesting.
>
> Thanks in advance,
> Herbert
>
>> 73
>
>> On 4/4/2016 4:27 PM, Attila Kinali wrote
Hi
In my case, the antennas were nice brand new NovaTel L/L2/L5 Glonass rated
survey antennas. The were up far enough to have a 360 degree view of the sky
down to 10 degrees of the horizon.
The runs I did used a number of modules, not just uBlox products. Some modules
did worse than others on p
Hi
Been there / done that:
The answers on position are off by 3 to 5 meters after multi day self survey.
The answers on time are off by even more than that would predict. (> 20 ns but
< 100 ns).
Bob
> On Apr 7, 2016, at 9:14 PM, Hal Murray wrote:
>
>
> kb...@n1k.org said:
>> I agree tha
me” problem.
Bob
>
> --
>Björn
>
> Originalmeddelande Från: Bob Camp
> Datum:2016-04-07 18:41 (GMT+07:00)
> Till: Bob Stewart , Discussion of precise time
> and frequency measurement Rubrik: Re:
> [time-nuts] LEA-M8T
> Hi
>
> Indeed, if you have
wrote:
>
> Hi Logan,
>
> I seem to remember Bob Camp mentioning that you can't have multiple satellite
> sources in the mix, because the other satellites are inferior to the GPS sats
> in timing. Maybe Bob or someone could address this. I would love to
> discover that
Hi
One thing to keep in mind:
If you are looking at stuff like sawtooth on most (but not all) GPS modules, the
counter you use to take the data does not have to be some sort of monster
machine. An old 5334 or 5335 will let you see the basic structure. If you spend
time
shopping, neither one is
Hi
Building a GPSDO *after* you have a lab full of gear is a very different
proposition than
building one because cash is tight and nobody mentioned the $43 surplus units.
There’s no right and wrong here, just a need to look at “why?” before you get
going.
Bob
> On Apr 5, 2016, at 5:40 PM,
Hi
This comes back (very much) to:
What is your objective?
If the full performance delivered by a surplus part is your objective, then the
Miller is not what you
are after. Since it sells for about 2X the current crop of surplus parts … that
is a bit of an issue as
well. There are a *lot* o
Hi
…. and this fulfills the requirement I mentioned:
“I just want to build one to say I’ve done it”
There is *absolutely* nothing at all wrong with that. If this is your goal, you
have
accomplished it. You likely have learned somethings along the way.
If you have a performance goal that is a
Hi
Even with an integer divide, it’s still going to toss in a full cycle of the
TCXO from time to time. It will
be an integer, except when it is not ….
Bob
> On Apr 4, 2016, at 7:27 PM, Attila Kinali wrote:
>
> On Mon, 4 Apr 2016 17:56:29 -0400
> Bob Camp wrote:
>
Hi
The variable frequency output on the uBlox (and other) GPS receivers has come
up many times in the past.
If you dig into the archives you can find quite a bit of data on the (lack of)
performance of the high(er) frequency
outputs from the various GPS modules. They all depend on cycle add / d
Hi
On a surplus cell phone GPSDO it’s going to be:
1) System has been down for a while (= something failed)
2) System is now working ( = something was fixed)
3) The primary system spec must now be met (+/- 100 ns time alignment).
4) The secondary system spec should be met (+/- 5x10^-8 frequency)
HI
Ok, let’s back up a bit. The first question is: why?
There are a few basic answers ( and many not so basic ones):
1) Because you want to save money over the $40 GPSDO’s that are on eBay.
2) Because you want to learn how a GPSDO works.
3) Because you want to make a GPSDO that performs bette
Hi
Like many others, I have had no problems with the Maxim RS-232 chips running at
3.6V. They have a nice table in the data sheet that includes the proper caps
for 3.6V operation. The data sheet clearly states that they will run from 3.0 V
to 5.5V supplies. They call out the capacitor values as
Hi
To contribute to the survey process, you need at least 4 satellites in the
“locked on” state. More is better and
4 may or may not get you into survey. If you are struggling to get enough
stateless, it’s usually an antenna issue.
Bob
> On Mar 30, 2016, at 1:38 PM, Vlad wrote:
>
>
>
> TB
Hi
There were (and maybe still are) SOT-89 versions of the 2N3804 and 3906. They
will handle more
power than most of the other versions. That gives you better Vce on the string.
They also have less
package inductance which helps tie the base to ground. If you are building some
of those circuits
Hi
> On Mar 27, 2016, at 9:23 PM, John Miles wrote:
>
>> BTW: I discovered that Timelab stops processing after 10'000'000 datapoints,
>> which is kind inconvenient when doing a long term measurment...
>
> It had better not! :) Any steps to reproduce?
>
It’s never stopped here …. I routinel
:11 PM, Attila Kinali wrote:
>
> On Sun, 27 Mar 2016 10:13:32 -0400
> Bob Camp wrote:
>
>> The “typical life” numbers on the tubes in the various Cesium standards
>> are fairly accurate. Most units that are well cared for “die” when the tube
>> goes out and come bac
Hi
There are a *lot* of chips that will divide down from a couple of GHz. Once you
have a chip, what do you do with it? There is more to a practical counter front
end than just the divider. Getting it all to work requires a bit of time and a
pretty good pc board.
This guy:
http://www.analog.
Hi
Telecom Rb prices have been running in the $100 to $150 range for quite a
while. The same is true of various surplus GPSDO’s with OCXO’s in them. If you
hop in your time machine and go back about 5 years ago, for about a year the
Rb’s came in (on and off) below $50 and GPSDO’s might come in
Hi
The “typical life” numbers on the tubes in the various Cesium standards
are fairly accurate. Most units that are well cared for “die” when the tube
goes out and come back to life when it’s replaced. The tube life dominates
the MTBF in this case.
Rb’s are a device that by it’s (possibly unfort
quency. A
118 MHz crystal shows much less impact from a given level of “air” than
something like a 2.5 MHz
5th overtone.
Bob
> 73
> KJ6UHN
> Alex
>
> On 2/2/2016 2:37 PM, Bob Camp wrote:
>> Hi
>>
>> I think you will find that the Russian versions were used
Hi
I wold not be at all surprised if it has a previous location surveyed into it’s
little
brain. As long as it still thinks it’s in Virginia (or wherever) it’s not going
to
lock up in it’s new home.
Depending where it came from, it might be a lab unit for initial design
checkout.
If HP ship
Hi
It’s probably bringing out both sides of the varicap to accomplish the same
sort of thing.
Bob
> On Mar 26, 2016, at 5:22 PM, Hal Murray wrote:
>
>> The one I have has both EFC+ and EFC- pins.
>
> Is that a differential input so you don't have to worry about ground offset
> shift when t
Hi
The 1150 OCXO has an EFC pin on it. The output *should* tune to both sides of
10 MHz.
Since this is an old box, the OCXO may have aged far enough to keep that from
happening.
If the EFC is railed, it is a good bet you need to tune the OCXO with the
mechanical trimmer
that is behind the seal
gt; effective in reducing noise whilst maintaining a flat response fro dc to
> around 50KHz.Small value resistors in series with the RF and LO ports are
> then useful in reducing the VSWR.
> Bruce
>
>
>On Saturday, 26 March 2016 10:10 AM, Bob Camp wrote:
>
>
>
>
Hi
> On Mar 25, 2016, at 1:55 PM, jimlux wrote:
>
> On 3/25/16 5:07 AM, Bob Camp wrote:
>> Hi
>>
>> The reverse isolation issue is indeed one of the weaknesses of this setup.
>> For testing
>> OCXO’s isolation is not a big deal. A normal OCOX has very
n amp?
>
> Bob
> ----
> On Thu, 3/24/16, Bob Camp wrote:
>
> Subject: Re: [time-nuts] Spectrum Analyzer Specifications
> To: "Discussion of precise time and frequency measurement"
>
> Date: Thursday, March 24, 2016, 5:48
on amp
> works well.
>
> I just bought the HELA10's on evaluation PCBs complete with brass metalwork..
>
> Bruce
>
>
>
>On Friday, 25 March 2016 4:02 PM, Bob Camp wrote:
>
>
> Hi
>
> If you think the HELA10 is fun at 10 MHz, try it at 1 MH
on is due to the presence of anti correlated thermal noise at
> the splitter outputs.
>
> Bruce
>
>
>On Friday, 25 March 2016 2:06 PM, Bob Camp wrote:
>
>
> Hi
>
> That’s another good point about the need to work out a target device. Both
> of
d could also be used for power supply and
> reference noise measurement.
>
> Bruce
>
> On Thursday, March 24, 2016 04:54:47 PM Bob Camp wrote:
>> Hi
>>
>> The board is pretty non-critical. It’s 90% audio. The biggest hassle is a
>> power supply. You would
AM, jimlux wrote:
>
> More like $40 in parts, without a board, etc.
> The RPD-1 is $20.70
> LT1678/LT1679 is a nice low noise opamp that does rail to rail and is about $5
> etc
>
>
>
> On 3/24/16 4:42 AM, Bob Camp wrote:
>> Hi
>>
>> Pretty simple:
&
they go lower?? Any
> recommended sound cards (or USB things that
> work like sound cards)?
>
> Rick
>
> On 3/24/2016 4:42 AM, Bob Camp wrote:
>> Hi
>>
>> Pretty simple:
>>
>> Double balanced mixer, RPD-1 is one option, there are others.
>>
9:04 AM, jimlux wrote:
>> More like $40 in parts, without a board, etc.
>> The RPD-1 is $20.70
>> LT1678/LT1679 is a nice low noise opamp that does rail to rail and is
>> about $5
>> etc
>>
>>
>>
>> On 3/24/16 4:42 AM, Bob Camp wrote:
>
two similar
oscillators. They run in quadrature and
you do a few “measure this with switch in position A” sort of things to set
things up each time.
Nothing exotic.
Bob
> On Mar 24, 2016, at 12:25 AM, Richard (Rick) Karlquist
> wrote:
>
>
>
> On 3/23/2016 3:56
HI
At least the last time I dug into it … the project is about 2% hardware and
98% software. Most of a Grandmaster is the same hardware that a slave uses.
Getting timing from various cell systems has been tried both commercially and
experimentally. The issue is that you are at the mercy of the
Hi
The “spurs and noise” you see plotted on an OCXO are the output of a
phase noise tester. No spectrum analyzer or SDR out there has enough
dynamic range to look at the phase noise on a good OCXO. You are dealing
with +10 dbm signals so “sensitivity” is not the issue. The range between
the sig
Hi
If you can see harmonics down to -60 dbc, that is about the most a normal
spectrum
analyzer will do for you on a frequency standard. This *assumes* the part has a
sine
wave output. Most standards are in the 10 MHz range, so an analyzer that will
work to
>= 40 MHz is probably a good idea.
C
> On Tue, Mar 22, 2016 at 3:23 PM, Bob Camp wrote:
>
>> Hi
>>
>> I’ve always found that pin 9 (EFC monitor) gave you a pretty good idea of
>> the lock status.
>>
>> Bob
>>
>>> On Mar 22, 2016, at 8:43 AM, Wayne (gmail)
>> wro
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