In a message dated 6/14/2007 10:03:40 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
Just a quick note about the HP 54720D. If you have 2 of the 4Gs plugins
installed are measuring a differential ECL signal; this combination yields
2pS rms jitter. I spent many hours characterizing
Said,
The 54720D setup was just 54720D/54721A(x2) 8133A.
The 8133A level was set to 400mVp-p @ 100 to 250MHz.
8133A Output to 54721A #1 Complement Output to 54721A #2.
H-P spec for this setup is 6ps rms jitter.
I was using a PC based post processing analysis package from
Amherst Associates
Hi Said,
We have a lot of fet probes in our lab, including Tek, hp and
Philips. Only one is useful for jitter measurements with the
Wavcrest, the hp 200MHz differential probe. I use it most of the time
single ended. It is the noise bandwidth of the probe that is of most
importance.
If
In a message dated 6/14/2007 11:29:47 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
was using a PC based post processing analysis package from
Amherst Associates (Mike Williams) which has slightly better
zero crossing interpolation than the 54720D. It requires down loading
the (large)
In a message dated 6/14/2007 11:34:04 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
If realy a fet probe is needed, than use a lowpass filter with enough
bandwidth after the probe. Most of the time the majority of the
jitter is still seen and the large noise bandwidth of the probe
Hi Said,
For jitter measurements the bandwidth, and thus the rise time, is not
important. Only the timing which is not affected by the rise time.
The filter has to settle enough so bandwidth must be high enough. A
low pass which increases the rise time is oke. For digital scopes,
and thus
In a message dated 6/10/2007 23:14:02 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
In a message dated 6/10/2007 19:04:25 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
However there are some capacitively (critically?) tuned resonant
circuits which will need some care to adjust
Soo, out of desperation, and because I actually had other plans for
today :-) I took the digital camera. That always works...
By the way, I will bring the laptop next week. You are going to earn
your free dinner :-)
Sounds like a plan! And a bad cable. :) Can you send it an ID? query
Measurements taken from 3325B at 1 MHz:
5370B reference: INT EXT (same 5087A as 3325B uses)
Square wave, 2v pk:15-20 ps 11-12 ps
Sine wave, 2v pk: 50-70 ps 30-35 ps
Square wave, 1v pk:20-25 ps 12-13 ps
Sine wave, 1v pk: 60-80 ps 40-45 ps
Square
Measurements taken from 3325B at 1 MHz:
5370B reference: INT EXT (same 5087A as 3325B uses)
Square wave, 2v pk:15-20 ps 11-12 ps
Sine wave, 2v pk: 50-70 ps 30-35 ps
Square wave, 1v pk:20-25 ps 12-13 ps
Sine wave, 1v pk: 60-80 ps 40-45 ps
In the case of the 5370, page 3-12 of the manual is where it came from (15.
Press STD DEV and +/- TI switch. Display should read less than 100 ps (this
reading is the instrument's jitter).)
I'm wondering if it would be more informative to make three
runs: one with A and B uncorrelated to ref;
Auftrag von Dr Bruce Griffiths
Gesendet: Sonntag, 10. Juni 2007 03:59
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] another Ebay mixup, 5370
John Miles wrote:
Pretty similar results here, taken from the 5370B's
rear-panel output
while running
Tom
Tom Van Baak wrote:
In the case of the 5370, page 3-12 of the manual is where it came from (15.
Press STD DEV and +/- TI switch. Display should read less than 100 ps (this
reading is the instrument's jitter).)
I'm wondering if it would be more informative to make three
runs: one
Dr Bruce Griffiths wrote:
I have a copy of a letter from David Chu detailing the then known
sources of differential nonlinearity in the 5370A.
These causes are principally crosstalk between the START and STOP
channels, and interaction between the mixers and the phase locked
oscillators.
PROTECTED]
Behalf Of Tom Van Baak
Sent: Sunday, June 10, 2007 1:20 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] another Ebay mixup, 5370
Measurements taken from 3325B at 1 MHz:
5370B reference: INT EXT (same 5087A as 3325B uses
I also have a spectrum plot of the HP5370A ref output.
http://www.ko4bb.com/Test_Equipment/HP_5370A/HP5370A.jpg
Yow. Dude, 7470.exe is your friend. :-P
-- john, KE5FX
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time-nuts mailing list
time-nuts@febo.com
If you send it to a cal lab, they will hook up a cable between the START and
REF jacks, note that the intrinsic jitter is less than 100 ps, slap a
sticker on it, and return it to you with the bill. As long as it passes
this and other tests in the manual, they won't tweak it any further, nor
[EMAIL PROTECTED] wrote:
Hi Bruce,
sounds like I can probably do the 200MHz multiplier board adjustment. I
wonder how much improvement that by itself, with the hardware mods will give?
I'm
just afraid to make things worse.
I used to work with TV's, and it took me years to learn
[EMAIL PROTECTED] wrote:
Hi Tom,
this was the recommended setup (by HP) for checking the internal noise. Feed
the 10MHz output back to the input using a short cable, and set the unit for
COMMON input, setting 50 Ohm impedance etc.
In the meantime I did some more tests, and found the
Hi Bruce,
and finally here is a plot of both the 5370B and the Fury 10MHz sine wave
spectras for comparison.
It only takes a 5 - 9th order passive lowpass filter to make a nice sine
wave out of the 5370B output, I wonder why HP didn't do that back then.
Also, I think the 10811 output
and frequency measurement
Subject: Re: [time-nuts] another Ebay mixup, 5370
[EMAIL PROTECTED] wrote:
Hi Tom,
this was the recommended setup (by HP) for checking the internal
noise. Feed the 10MHz output back to the input using a short cable,
and set the unit for COMMON input, setting 50
In a message dated 6/9/2007 17:00:32 Pacific Daylight Time, [EMAIL PROTECTED]
writes:
One of my 5370A's had a severely distorted sine out, which Bruce helped me
trace to a bad solder joint
Didier
Hi Didier,
was it worse than the scope picture I just sent out?
thanks,
Said
[EMAIL PROTECTED] wrote:
Hi Bruce,
just found out that the 10MHz output looks very much like the picture in the
5370B service manual.
I am not impressed. HP could have done a better job on that output :( Maybe
my unit isn't broken after all, maybe the 200ps RMS jitter is normal?
I am definitely not qualified to calibrate them for money. I will generally
take a look at peoples' gear for free as long as they understand that
they're lucky if it works as well when it leaves my bench as it did when
they brought it over. :)
-- john, KE5FX
Wow, 10ps RMS is nice. I would be
:[EMAIL PROTECTED]
Behalf Of [EMAIL PROTECTED]
Sent: Saturday, June 09, 2007 4:44 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] another Ebay mixup, 5370
In a message dated 6/9/2007 14:56:04 Pacific Daylight Time,
[EMAIL PROTECTED] writes:
Can you send an image of the rear panel
John Miles wrote:
Pretty similar results here, taken from the 5370B's rear-panel output while
running on the internal 10811B (attached). Indicated jitter with this setup
is about the same as it was on the ext ref via the 5087A (10-12 ps).
I've seen this counter return self-test jitter
Said,
You sent pictures of the Fury's waveform, only the spectrum of the 5370.
I did not look at the spectrum at the time, bu the waveform on the scope
was low in amplitude and looked like 30 MHz with some 10 MHz component.
It turns out a cap in the output filter was not making contact, and
John Miles wrote:
Pretty similar results here, taken from the 5370B's rear-panel output while
running on the internal 10811B (attached). Indicated jitter with this setup
is about the same as it was on the ext ref via the 5087A (10-12 ps).
I've seen this counter return self-test jitter
] another Ebay mixup, 5370
It only goes up to 20-25 ps here, measuring the Thunderbolt-5087A output
while running from the internal reference. About the same as what I see
when measuring either the 8640B or 8662A. Definitely some
correlation going
on, but not as significant a difference
The unit is actually relatively young (1990's), and has virtually no dust
whatsoever in it. Seems to have had very low usage. The actual 10MHz is
pretty
accurate, to within 10mHz.
Has anyone else measured the 5370B output jitter?
bye,
Said
Oh so many projects, so little time. I
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