Re: [time-nuts] GPSDO 10 MHz Distribution Amp
At 04:39 PM 6/21/2009, time-nuts-request@febo.com wrote:
Send time-nuts mailing list submissions to
time-nuts@febo.com
To subscribe or unsubscribe via the World Wide Web, visit
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
or, via email, send a message with subject or body 'help' to
time-nuts-request@febo.com
DEMI (Down East Microwave) has 10 MHz distibution amplifers for
sale, either in kit form or built and tested. The kits ( all the
parts, but sans connectors and enclosure) are only $25 and delivery was quick.
Each output is driven by an ERA device and has a two stage low pass
filter. I just put one together and it took about an hour. Damn
some of SMD chip capacitors are really small ! But I'm proud that at
my age (77) I can still solder with a steady hand.
Chuck, W7CS
You can reach the person managing the list at
time-nuts-owner@febo.com
When replying, please edit your Subject line so it is more specific
than "Re: Contents of time-nuts digest..."
Today's Topics:
1. Re: LF power supply noise (Mike Monett)
2. Re: Thunderbolts for sale (Richard W. Solomon)
3. Re: Bad capacitors (was Volt-nuts cooperation?) (Dave Mallery)
4. Re: GPSDO 10 MHz Distribution Amp (Don Key)
5. Re: GPSDO 10 MHz Distribution Amp (dave powis)
Message: 1
Date: Sun, 21 Jun 2009 15:27:54 -0300
From: "Mike Monett" xde-l2g3@myamail.com
Subject: Re: [time-nuts] LF power supply noise
To: "" time-nuts@febo.com
Message-ID: mailman.2041.1245627544.2451.time-nuts@febo.com
Content-Type: text/plain; charset="iso-8859-1"
Mike,
[...]
One of the reasons I was attracted to the 543310A was it could
display 14 digits of frequency in one second. Sine then, I have
figured a way to resolve 16 digits in one second, so that part of
the spec is no longer interesting.
As was described by J. J. Snyder in "An Ultra-High Resolution
Frequency Meter" in the FCS 1981 (as available from IEEE UFFC) I
assume, basically using the fact that adding more measurements in
a dense time raises the degrees of freedom and allows for quicker
interpolation.
Modern counters like HP 53131, HP 53132 as well as Pendulum CNT-90
or Fluke 6690 uses similar approaches.
I can't find any copies that are not payware, but it is unlikely
there is any connection between the methods.
Conventional averaging methods are limited by the exponential rise
in number of samples that are required to improve the SNR. The
measurement ends up taking too long, or the system drifts which
renders the mesurement useless.
This provides an effective barrier to the amount of improvement
possible in SNR, and the available precision that is possible with
conventional technology.
Binary Sampling works a completely different way. It ignores the
amplitude of the sample, and only records the direction of the
error.
According to the Central Limit Theorem, the mean of Gaussian noise
is zero. This forces the Binary Sampler to converge on the true
value of the signal, and ignore the error caused by the amplitude of
the sample.
This is a really big thing. The problem of using averaging to
improve sigma has existed for over 109 years. And nobody has been
able to solve it up till now.
With a heterodyne sampling system, or conventional mixer technology,
the sample delta is the offset frequency divided by the square of
the reference frequency:
Delta = Offset / Ref * Ref
With a delta of 1Hz and reference of 1 MHz, the sample delta is
1 / (1e6)^2 = 1 / 1e12,
or 1 picosecond.
Since the Binary Sampler discards noise, the result is 1 picosecond
resolution in 1 second.
I show this on my web site. The schematic for the measurement is
shown in Fig. 1 at
http://pstca.com/sampler/design.htm
A simple boxcar smoother is used to integrate the samples. The
result with different smoothing values is shown at
http://pstca.com/sampler/smooth.htm
A system with 18.38 ps rms jitter would require averaging 338
waveforms to obtain 1ps rms jitter. With conventional sampling
technology, this would require 169 seconds, and the system would
probably drift during the measurement, rendering the measurement
invalid.
So it is not possible to obtain this amount of improvement in this
system, and the measurement is impossible.
The Binary Sampler gives 1ps resolution in 1 second. This is shown
in Fig. 4 at
http://pstca.com/sampler/binsamp.htm
No other system can achieve this performance. And anyone with
sufficient skill can duplicate this result at home.
Extending this to higher frequency, it should be possible to obtain
a 1Hz offset at 100MHz with 1 uHz resolution. This gives
1 / (1e8)^2 = 1e-16 resolution in 1 second.
I do not think any existing equipment from HP, Fluke, or Pendulum or
anyone else can come close to matching this level of performance.
Also, existing technology must deal with noise and the averaging
problem. This eliminates much of the performance boundaries from
consideration.
As a result, conventional technology cannot reach 1e-16 in one
second.
As being reported, such mechanisms does not fair well with ADEV
calculations, and especially the overlapping variants of ADEV and
den MDEV and TDEV which was inspired by that particular article,
so using it twice forms unwanted filters.
My approach delivers continuous samples. No missing or extra bits.
The 543310A can do a single-shot time measurement with a
resolution of 200ps, and gets down to 1ps with averaging. The
HP5370B does 20ps single-shot, and will resolve 100fs with
averaging. But I have figured a way to measure 2ps single-shot,
and a bit better with averaging. So that part of the spec is not
so interesting any more.
I assume you really mean HP 53310A and not HP 543310A, even if
your typing is consistent. The listed numbers is when weigthing in
how various jitter sources combine upon averaging and should be
considered a bit conservative.
By all means describe what you mean by 2 ps single-shot
resolution.
That will cure me of trying to type complex numbers when copy and
paste works so much better. But now I have to try and figure out
what your "weigthing" really means:)
The 2ps single shot is dead straight conventional time-to-time
conversion. Nothing new there, except I think I have some new tricks
on stabilizing the circuits against drift, and providing a much
faster response to the zero-crossing at the end of the timing
interval. All these reduce the noise in the sampling process.
But the real trick is applying the Binary Sampling technique to the
result. That allows a huge reduction in the noise from the sampling
process, and converges rapidly on a much more precise solution.
The 543310A will display the phase and frequency changes in a PLL
step response. But you can get the frequency response just by
looking at the VCO DC error voltage. And if you look at the
voltage across the bottom capacitor in a type 3 loop, you get the
phase response. Here's a picture:
|
--- C1
---
|
|----------O < - Phase Error
| |
--- C2 \
--- / R1
| \
| |
--- ---
- -
You should recall that when HP built their line of analyzers, they
where thinking "what can we make this cool ZDT core do?" rather
than attempting to build the best analyzer for all responsens.
I have a slightly different impression. I sold a lot of equipment to
Boisie, Idaho, and I used to make a lot of trips there in my Piper
Malibu, which was about the only realistic way of getting there from
San Jose:
http://www.jetphotos.net/viewphoto.php?id=5874208&nseq=0
There was a lot of political infighting at Boisie involved in
development of new equipment. The winner pretty much had whatever
say he wanted in the direction, and he ignored the input from other
competent engineers.
As a result, the equipment was limited by that individual's scope
and abilities. The result is much of HP's equipment suffered.
One example is the 20ps single-shot resolution of the HP 5370B has
never been matched by any later equipment, as far as I know. A few
engineers at Boisie complained bitterly about the loss.
So about the only thing left of interest is histograms of the
jitter. Unfortunately, the 543310A cannot store enough samples to
really make an interesting graph. What I would like to be able to
do is similar to an invention I made for the disk industry long
ago, called Phase Margin Analysis. There is a brief description
on my web page at
Somewhere in my map of apps there is a HP appnote for doing the
same, to discs, intended for disc industry, back in the days.
That may very well be a result of my invention, which occurred in
1970, was published in 1979, and was copied by IBM in the 1990's.
But I have all the HP appnotes for disk. I don't recall any of them
describing what I show above. Can you provide more information?
[...]
The 53310A was a nice convenient tool at its time, but it's
performance isn't up to spec with modern times. It seems like HP
didn't pursue it into much deeper levels after its VXI
instruments, where as others went deeper.
I'm not sure about this, but I don't think there is any later HP
equipment that can approach what the 53310A does.
But I can now match or beat it by orders of magnitude. This is
sufficient for our current needs, but I will always be working on
newer technology to break through the limits we now have.
Cheers,
Magnus
Thanks,
Mike
Message: 2
Date: Sun, 21 Jun 2009 14:24:25 -0700 (GMT-07:00)
From: "Richard W. Solomon" w1ksz@earthlink.net
Subject: Re: [time-nuts] Thunderbolts for sale
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID:
10269879.1245619465545.JavaMail.root@mswamui-blood.atl.sa.earthlink.net
Content-Type: text/plain; charset=UTF-8
Did you receive my e-mail ?
73, Dick, W1KSZ
-----Original Message-----
From: Brian Kirby kilodelta4foxmike@gmail.com
Sent: Jun 19, 2009 9:49 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Thunderbolts for sale
I will have two Trimble Thunderbolts GPSDO, that I will be selling.
Both were bought thru the Time-Nuts purchases. There is nothing wrong
with these units, they are operational, and surplus to my needs.
One unit comes with the Ault power supply and power connector.
The second unit comes without a power supply and I will be furnishing a
pig-tailed power lead connector.
I do not have pay-pal (sorry, I gave up on *bay...) and I can send COD.
I can only make this offer for the lower 48 of the United States.
If you are interested, please contact me off this list.
Brian Kirby - KD4FM
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
and follow the instructions there.
Message: 3
Date: Sun, 21 Jun 2009 16:12:35 -0600
From: Dave Mallery dave.mallery@gmail.com
Subject: Re: [time-nuts] Bad capacitors (was Volt-nuts cooperation?)
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID:
3010c9470906211512r73738824xf7c33fb2fc3f7757@mail.gmail.com
Content-Type: text/plain; charset=windows-1252
hi
many thanks for the heads-up on the pg505 caps!
they are supposed to be 350 ufd at 75 vdc. they are anything but.
(goes back to mixing/matching caps...)
dave
On Sun, Jun 21, 2009 at 10:21 AM, Mark Sims holrum@hotmail.com wrote:
The problems I saw were mostly hard failures in the caps
(opens/shorts/etc). These were in both power caps and signal caps.
One lot that I saw was a group of 12 Mettler scales. 6 were used daily and
6 were never used backup units. When the company shut down the operations
that used the scales, they were sold. All the used units worked
fine. The
backup units all had capacitor problems.
I also bought a lot of new-in-box Tektronix TM500 modules. Most wound up
having flakey capacitors. BTW, EVERY (new or used) Tek PG505 pulse
generator you will come across will have bad power supply filter caps...
unless they were replaced.
Does this happen even if the electrolytics are reformed before use?
Lauren found her dream laptop. Find the PC that?s right for you.
http://www.microsoft.com/windows/choosepc/?ocid=ftp_val_wl_290
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.
--
Dave Mallery, K5EN (ubuntu linux 9.04)
HC31 Box 99E; Williamsburg, NM 87942
no gates...
no windows!
free at last!
linux counter #64628 (since 1997)
"People aren't as dumb as Microsoft needs them to be."
--PJ, May 2007
Message: 4
Date: Mon, 22 Jun 2009 00:14:23 +0100
From: "Don Key" don.key@ntlworld.com
Subject: Re: [time-nuts] GPSDO 10 MHz Distribution Amp
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Message-ID: 04B4AD11A8FC49DAA586C95521161AEE@JimPC
Content-Type: text/plain; format=flowed; charset="UTF-8";
reply-type=original
Hi Dave
Do you supply your DA1-4L distribution amp as a ready-built unit?
Your PDF Technical manual says you do, but there are only prices for the
kits on your ordering page.
Cheers.
Jim.
----- Original Message -----
From: "dave powis" g4hup@btinternet.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Sunday, June 21, 2009 5:34 PM
Subject: Re: [time-nuts] GPSDO 10 MHz Distribution Amp
Hi Paul,
Sounds a reasonable approach to me where an equal 2 way split is needed, and
you already have adequate signal level available. May not be up to
'time-nuts' precision etc, but it is a practical method that will give what
you need. If you ever need to remove one Rig, just remember to terminate
the unused split output in 50R!
However, when you get yourself an analyser, sig gen or counter that takes
the 10MHz reference, then you will need a DA! Comeback to me
(http://g4hup.com) or TAPR then!
73,
Dave
From: Paul Christensen w9ac@arrl.net
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Sunday, 21 June, 2009 5:18:51 PM
Subject: [time-nuts] GPSDO 10 MHz Distribution Amp
In the next couple weeks, I plan on distributing the output of my GPSDO to a
pair of Icom transceivers. I've thought about using a DA like the TAPR
TADD-1, but it seems that I can simply split the output of the +13 dBm GPSDO
with a Z=50, 3dB equal power divider, that will yield an output of ~ +9.5
dBm to each transceiver.
I can't foresee any port isolation issues that would make necessitate the
use of the DA for this application and the 3 dB "hit" in level to each
transceiver still seems reasonable for proper transceiver operation. Am I
not considering something important? Also, I do not want to add any noise
with such a distribution that would in any way destroy the excellent phase
noise characteristics of my GPSDO. Thoughts?
Paul, W9AC
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.
Message: 5
Date: Sun, 21 Jun 2009 16:38:58 -0700 (PDT)
From: dave powis g4hup@btinternet.com
Subject: Re: [time-nuts] GPSDO 10 MHz Distribution Amp
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Message-ID: 720079.15159.qm@web86306.mail.ird.yahoo.com
Content-Type: text/plain; charset=utf-8
Hi Jim,
Thanks for the enquiry. I do prefer to supply kits, as I am not a
full time business, and need to work for a living! However, on
request I do build units, so if that is what you want, I can quote for that.
Cost for the DA1-4L assembled will depend on the connectors you want
fitted - if you note from the page, I don't supply connectors with
the kit, since some folks want BNC's to fit in their systems, while
others want SMA's. Let me know what connector you are interested
in, and where the finished unit is to be shipped to, and I'll put a
quote together.
Best 73,
Dave, G4HUP
From: Don Key don.key@ntlworld.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Monday, 22 June, 2009 12:14:23 AM
Subject: Re: [time-nuts] GPSDO 10 MHz Distribution Amp
Hi Dave
Do you supply your DA1-4L distribution amp as a ready-built unit?
Your PDF Technical manual says you do, but there are only prices for
the kits on your ordering page.
Cheers.
Jim.
----- Original Message ----- From: "dave powis" g4hup@btinternet.com
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Sunday, June 21, 2009 5:34 PM
Subject: Re: [time-nuts] GPSDO 10 MHz Distribution Amp
Hi Paul,
Sounds a reasonable approach to me where an equal 2 way split is
needed, and you already have adequate signal level available. May
not be up to 'time-nuts' precision etc, but it is a practical method
that will give what you need. If you ever need to remove one Rig,
just remember to terminate the unused split output in 50R!
However, when you get yourself an analyser, sig gen or counter that
takes the 10MHz reference, then you will need a DA! Comeback to me
(http://g4hup.com) or TAPR then!
73,
Dave
From: Paul Christensen w9ac@arrl.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sunday, 21 June, 2009 5:18:51 PM
Subject: [time-nuts] GPSDO 10 MHz Distribution Amp
In the next couple weeks, I plan on distributing the output of my
GPSDO to a pair of Icom transceivers. I've thought about using a DA
like the TAPR TADD-1, but it seems that I can simply split the
output of the +13 dBm GPSDO with a Z=50, 3dB equal power divider,
that will yield an output of ~ +9.5 dBm to each transceiver.
I can't foresee any port isolation issues that would make
necessitate the use of the DA for this application and the 3 dB
"hit" in level to each transceiver still seems reasonable for proper
transceiver operation. Am I not considering something
important? Also, I do not want to add any noise with such a
distribution that would in any way destroy the excellent phase noise
characteristics of my GPSDO. Thoughts?
Paul, W9AC
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
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
End of time-nuts Digest, Vol 59, Issue 74