JN
Jean-Louis Noel
Sat, Mar 12, 2011 3:45 PM
23.2pS I think it is a bit too much.
The manual says to expect jitter of 35 ps typical, 100 max. One of mine
is ~30, the other ~20.
Yes, I saw that!
But, where is the logical when your display starts at 100fS?
Bye,
Jean-Louis
Hi Mike,
From: "Mike S" <mikes@flatsurface.com>
>>23.2pS I think it is a bit too much.
>>Could you check yours?
> The manual says to expect jitter of 35 ps typical, 100 max. One of mine
> is ~30, the other ~20.
Yes, I saw that!
But, where is the logical when your display starts at 100fS?
Bye,
Jean-Louis
M
mikes@flatsurface.com
Sat, Mar 12, 2011 4:47 PM
At 10:45 AM 3/12/2011, Jean-Louis Noel wrote...
Yes, I saw that!
But, where is the logical when your display starts at 100fS?
A mean (average) measurement improves things by the square root of the
number of measurements, if I'm not mistaken. So, if you measure 100,000
times, then a 35 ps jitter is reduced to ~ 110 fs ( 35 ps /
sqrt(100000) = 35 ps / ~316 = ~110 ps). Using HPIB, you can do
measurements up to 2^24-1 = 16777215 times, so 35/4096 = ~9 fs.
There are other error sources which make the actual accuracy worse than
that, though. For instance, HP gives a +- 1 ns "Sytematic error" for TI
measurement, regardless of the number of measurements. They say it's
typical 300 ps and can be reduced to 30 ps. I'm not sure if that is
random or what consistency it has between different measurements. It
may only effect absolute accuracy, not relative accuracy when comparing
measurements.
Someone will tell me if I'm wrong.
At 10:45 AM 3/12/2011, Jean-Louis Noel wrote...
>Yes, I saw that!
>But, where is the logical when your display starts at 100fS?
A mean (average) measurement improves things by the square root of the
number of measurements, if I'm not mistaken. So, if you measure 100,000
times, then a 35 ps jitter is reduced to ~ 110 fs ( 35 ps /
sqrt(100000) = 35 ps / ~316 = ~110 ps). Using HPIB, you can do
measurements up to 2^24-1 = 16777215 times, so 35/4096 = ~9 fs.
There are other error sources which make the actual accuracy worse than
that, though. For instance, HP gives a +- 1 ns "Sytematic error" for TI
measurement, regardless of the number of measurements. They say it's
typical 300 ps and can be reduced to 30 ps. I'm not sure if that is
random or what consistency it has between different measurements. It
may only effect absolute accuracy, not relative accuracy when comparing
measurements.
Someone will tell me if I'm wrong.
SJ
Said Jackson
Sat, Mar 12, 2011 5:00 PM
Hi,
The average will approach 0.0 as the number of samples is increased, but not the standard deviation.. The value displayed by their unit is standard deviation.
Bye,
Said
Sent from my iPad
On Mar 12, 2011, at 8:47, mikes@flatsurface.com (Mike S) wrote:
At 10:45 AM 3/12/2011, Jean-Louis Noel wrote...
Yes, I saw that!
But, where is the logical when your display starts at 100fS?
A mean (average) measurement improves things by the square root of the number of measurements, if I'm not mistaken. So, if you measure 100,000 times, then a 35 ps jitter is reduced to ~ 110 fs ( 35 ps / sqrt(100000) = 35 ps / ~316 = ~110 ps). Using HPIB, you can do measurements up to 2^24-1 = 16777215 times, so 35/4096 = ~9 fs.
There are other error sources which make the actual accuracy worse than that, though. For instance, HP gives a +- 1 ns "Sytematic error" for TI measurement, regardless of the number of measurements. They say it's typical 300 ps and can be reduced to 30 ps. I'm not sure if that is random or what consistency it has between different measurements. It may only effect absolute accuracy, not relative accuracy when comparing measurements.
Someone will tell me if I'm wrong.
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.
Hi,
The average will approach 0.0 as the number of samples is increased, but not the standard deviation.. The value displayed by their unit is standard deviation.
Bye,
Said
Sent from my iPad
On Mar 12, 2011, at 8:47, mikes@flatsurface.com (Mike S) wrote:
> At 10:45 AM 3/12/2011, Jean-Louis Noel wrote...
>> Yes, I saw that!
>> But, where is the logical when your display starts at 100fS?
>
> A mean (average) measurement improves things by the square root of the number of measurements, if I'm not mistaken. So, if you measure 100,000 times, then a 35 ps jitter is reduced to ~ 110 fs ( 35 ps / sqrt(100000) = 35 ps / ~316 = ~110 ps). Using HPIB, you can do measurements up to 2^24-1 = 16777215 times, so 35/4096 = ~9 fs.
>
> There are other error sources which make the actual accuracy worse than that, though. For instance, HP gives a +- 1 ns "Sytematic error" for TI measurement, regardless of the number of measurements. They say it's typical 300 ps and can be reduced to 30 ps. I'm not sure if that is random or what consistency it has between different measurements. It may only effect absolute accuracy, not relative accuracy when comparing measurements.
>
> Someone will tell me if I'm wrong.
>
> _______________________________________________
> 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.
MS
Mark Spencer
Sat, Mar 12, 2011 5:14 PM
----- Original Message ----
From: Jean-Louis Noel jln@stben.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sat, March 12, 2011 2:26:48 AM
Subject: [time-nuts] noise of a 5370
Hi,
I have a question for you guys.
I am currently fixing a 5370B and when I check the internal noise I got
23.2pS I think it is a bit too much.
Could you check yours noise?
- Connect a cable between the rear panel FREQ STD OUT to front panel START
input connector
- Set the input impedances at 50 ohms
- Attenuator switches at /1
- AC/DC switches to DC
- Input slope switches to positive (high)
- Level controls to preset
- START COM
- display rate fully clockwise
- SAMPLE SIZE 10K
- STATISTICS STD DEV
I got 23.2ps with 2ps unstability.
Is that OK?
Thanks for your help.
Bye,
Jean-Louis
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.
----- Original Message ----
From: Jean-Louis Noel <jln@stben.net>
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Sent: Sat, March 12, 2011 2:26:48 AM
Subject: [time-nuts] noise of a 5370
Hi,
I have a question for you guys.
I am currently fixing a 5370B and when I check the internal noise I got
23.2pS I think it is a bit too much.
Could you check yours noise?
1) Connect a cable between the rear panel FREQ STD OUT to front panel START
input connector
2) Set the input impedances at 50 ohms
3) Attenuator switches at /1
4) AC/DC switches to DC
5) Input slope switches to positive (high)
6) Level controls to preset
7) START COM
8) display rate fully clockwise
9) SAMPLE SIZE 10K
10) STATISTICS STD DEV
I got 23.2ps with 2ps unstability.
Is that OK?
Thanks for your help.
Bye,
Jean-Louis
_______________________________________________
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.
MS
Mark Spencer
Sat, Mar 12, 2011 5:22 PM
Mine shows approx 25 ps.
----- Original Message ----
From: Jean-Louis Noel jln@stben.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sat, March 12, 2011 2:26:48 AM
Subject: [time-nuts] noise of a 5370
Hi,
I have a question for you guys.
I am currently fixing a 5370B and when I check the internal noise I got
23.2pS I think it is a bit too much.
Could you check yours noise?
- Connect a cable between the rear panel FREQ STD OUT to front panel START
input connector
- Set the input impedances at 50 ohms
- Attenuator switches at /1
- AC/DC switches to DC
- Input slope switches to positive (high)
- Level controls to preset
- START COM
- display rate fully clockwise
- SAMPLE SIZE 10K
- STATISTICS STD DEV
I got 23.2ps with 2ps unstability.
Is that OK?
Thanks for your help.
Bye,
Jean-Louis
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.
Mine shows approx 25 ps.
----- Original Message ----
From: Jean-Louis Noel <jln@stben.net>
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Sent: Sat, March 12, 2011 2:26:48 AM
Subject: [time-nuts] noise of a 5370
Hi,
I have a question for you guys.
I am currently fixing a 5370B and when I check the internal noise I got
23.2pS I think it is a bit too much.
Could you check yours noise?
1) Connect a cable between the rear panel FREQ STD OUT to front panel START
input connector
2) Set the input impedances at 50 ohms
3) Attenuator switches at /1
4) AC/DC switches to DC
5) Input slope switches to positive (high)
6) Level controls to preset
7) START COM
8) display rate fully clockwise
9) SAMPLE SIZE 10K
10) STATISTICS STD DEV
I got 23.2ps with 2ps unstability.
Is that OK?
Thanks for your help.
Bye,
Jean-Louis
_______________________________________________
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.
M
mikes@flatsurface.com
Sat, Mar 12, 2011 5:27 PM
At 12:00 PM 3/12/2011, Said Jackson wrote...
The average will approach 0.0 as the number of samples is increased,
but not the standard deviation.. The value displayed by their unit is
standard deviation.
If you're measuring jitter of an external signal, accuracy is obviously
much worse than the internal jitter. But if you're measuring TI, both
the instrument and signal jitter get reduced with more measurements,
leaving a more accurate TI, doesn't it?
Being designed and sold as a TI analyzer, that seems right. It seems
the jitter test is mostly to make sure the unit is operating properly.
If I recall correctly, internal jitter is affected by tweaking the 200
MHz multiplier. Lacking a proper spectrum analyzer, that's the only
calibration I have been unable to do.
At 12:00 PM 3/12/2011, Said Jackson wrote...
>The average will approach 0.0 as the number of samples is increased,
>but not the standard deviation.. The value displayed by their unit is
>standard deviation.
If you're measuring jitter of an external signal, accuracy is obviously
much worse than the internal jitter. But if you're measuring TI, both
the instrument and signal jitter get reduced with more measurements,
leaving a more accurate TI, doesn't it?
Being designed and sold as a TI analyzer, that seems right. It seems
the jitter test is mostly to make sure the unit is operating properly.
If I recall correctly, internal jitter is affected by tweaking the 200
MHz multiplier. Lacking a proper spectrum analyzer, that's the only
calibration I have been unable to do.
JN
Jean-Louis Noel
Sat, Mar 12, 2011 7:28 PM
I am currently fixing a 5370B and when I check the internal noise I got
23.2pS I think it is a bit too much.
So, it's not too bad for a device saved from trash!
Ebay 120681814403.
Thanks.
Bye,
Jean-Louis
Hi Everyone,
From: "Mark Spencer" <mspencer12345@yahoo.ca>
> Mine shows approx 25 ps.
> I am currently fixing a 5370B and when I check the internal noise I got
> 23.2pS I think it is a bit too much.
So, it's not too bad for a device saved from trash!
Ebay 120681814403.
Thanks.
Bye,
Jean-Louis
RA
Robert Atkinson
Sat, Mar 12, 2011 8:45 PM
Hi,
My 5370B gives about 21ps
Robert G8RPI.
From: Jean-Louis Noel jln@stben.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sat, 12 March, 2011 10:26:48
Subject: [time-nuts] noise of a 5370
Hi,
I have a question for you guys.
I am currently fixing a 5370B and when I check the internal noise I got
23.2pS I think it is a bit too much.
Could you check yours noise?
- Connect a cable between the rear panel FREQ STD OUT to front panel START
input connector
- Set the input impedances at 50 ohms
- Attenuator switches at /1
- AC/DC switches to DC
- Input slope switches to positive (high)
- Level controls to preset
- START COM
- display rate fully clockwise
- SAMPLE SIZE 10K
- STATISTICS STD DEV
I got 23.2ps with 2ps unstability.
Is that OK?
Thanks for your help.
Bye,
Jean-Louis
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.
Hi,
My 5370B gives about 21ps
Robert G8RPI.
________________________________
From: Jean-Louis Noel <jln@stben.net>
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Sent: Sat, 12 March, 2011 10:26:48
Subject: [time-nuts] noise of a 5370
Hi,
I have a question for you guys.
I am currently fixing a 5370B and when I check the internal noise I got
23.2pS I think it is a bit too much.
Could you check yours noise?
1) Connect a cable between the rear panel FREQ STD OUT to front panel START
input connector
2) Set the input impedances at 50 ohms
3) Attenuator switches at /1
4) AC/DC switches to DC
5) Input slope switches to positive (high)
6) Level controls to preset
7) START COM
8) display rate fully clockwise
9) SAMPLE SIZE 10K
10) STATISTICS STD DEV
I got 23.2ps with 2ps unstability.
Is that OK?
Thanks for your help.
Bye,
Jean-Louis
_______________________________________________
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.
SJ
Said Jackson
Sun, Mar 13, 2011 2:51 AM
Yes, the TI will get more accurate with time. But the setup suggested in previous email doesn't measure TI.
It measures the standard deviation of that TI. Big difference, two completely different numbers. The SD number is essentially a measure of the absolute amplitude of the noise. Since it is an absolute measurement, it doesn't converge to 0ps.
That number will quickly converge to about 20ps to 50ps. It will not get smaller with larger sample sets.
Please check the 5370 manual what standard deviation means, it will make sense then.
Bye,
Said
Sent from my iPad
On Mar 12, 2011, at 9:27, mikes@flatsurface.com (Mike S) wrote:
At 12:00 PM 3/12/2011, Said Jackson wrote...
The average will approach 0.0 as the number of samples is increased, but not the standard deviation.. The value displayed by their unit is standard deviation.
If you're measuring jitter of an external signal, accuracy is obviously much worse than the internal jitter. But if you're measuring TI, both the instrument and signal jitter get reduced with more measurements, leaving a more accurate TI, doesn't it?
Being designed and sold as a TI analyzer, that seems right. It seems the jitter test is mostly to make sure the unit is operating properly.
If I recall correctly, internal jitter is affected by tweaking the 200 MHz multiplier. Lacking a proper spectrum analyzer, that's the only calibration I have been unable to do.
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.
Yes, the TI will get more accurate with time. But the setup suggested in previous email doesn't measure TI.
It measures the standard deviation of that TI. Big difference, two completely different numbers. The SD number is essentially a measure of the absolute amplitude of the noise. Since it is an absolute measurement, it doesn't converge to 0ps.
That number will quickly converge to about 20ps to 50ps. It will not get smaller with larger sample sets.
Please check the 5370 manual what standard deviation means, it will make sense then.
Bye,
Said
Sent from my iPad
On Mar 12, 2011, at 9:27, mikes@flatsurface.com (Mike S) wrote:
> At 12:00 PM 3/12/2011, Said Jackson wrote...
>> The average will approach 0.0 as the number of samples is increased, but not the standard deviation.. The value displayed by their unit is standard deviation.
>
> If you're measuring jitter of an external signal, accuracy is obviously much worse than the internal jitter. But if you're measuring TI, both the instrument and signal jitter get reduced with more measurements, leaving a more accurate TI, doesn't it?
>
> Being designed and sold as a TI analyzer, that seems right. It seems the jitter test is mostly to make sure the unit is operating properly.
>
> If I recall correctly, internal jitter is affected by tweaking the 200 MHz multiplier. Lacking a proper spectrum analyzer, that's the only calibration I have been unable to do.
>
> _______________________________________________
> 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.
BG
Bruce Griffiths
Sun, Mar 13, 2011 2:54 AM
Whilst the standard deviation of the individual measures of TI will be
invariant with the number (N) of TI measurements made (provided the
environment doesn't change and the noise remains white), the standard
deviation of the averaged TI will decrease with increasing N until drift
and non white noise components dominate.
Bruce
Said Jackson wrote:
Yes, the TI will get more accurate with time. But the setup suggested in previous email doesn't measure TI.
It measures the standard deviation of that TI. Big difference, two completely different numbers. The SD number is essentially a measure of the absolute amplitude of the noise. Since it is an absolute measurement, it doesn't converge to 0ps.
That number will quickly converge to about 20ps to 50ps. It will not get smaller with larger sample sets.
Please check the 5370 manual what standard deviation means, it will make sense then.
Bye,
Said
Sent from my iPad
On Mar 12, 2011, at 9:27, mikes@flatsurface.com (Mike S) wrote:
At 12:00 PM 3/12/2011, Said Jackson wrote...
The average will approach 0.0 as the number of samples is increased, but not the standard deviation.. The value displayed by their unit is standard deviation.
If you're measuring jitter of an external signal, accuracy is obviously much worse than the internal jitter. But if you're measuring TI, both the instrument and signal jitter get reduced with more measurements, leaving a more accurate TI, doesn't it?
Being designed and sold as a TI analyzer, that seems right. It seems the jitter test is mostly to make sure the unit is operating properly.
If I recall correctly, internal jitter is affected by tweaking the 200 MHz multiplier. Lacking a proper spectrum analyzer, that's the only calibration I have been unable to do.
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.
Whilst the standard deviation of the individual measures of TI will be
invariant with the number (N) of TI measurements made (provided the
environment doesn't change and the noise remains white), the standard
deviation of the averaged TI will decrease with increasing N until drift
and non white noise components dominate.
Bruce
Said Jackson wrote:
> Yes, the TI will get more accurate with time. But the setup suggested in previous email doesn't measure TI.
>
> It measures the standard deviation of that TI. Big difference, two completely different numbers. The SD number is essentially a measure of the absolute amplitude of the noise. Since it is an absolute measurement, it doesn't converge to 0ps.
>
> That number will quickly converge to about 20ps to 50ps. It will not get smaller with larger sample sets.
>
> Please check the 5370 manual what standard deviation means, it will make sense then.
>
> Bye,
> Said
>
> Sent from my iPad
>
> On Mar 12, 2011, at 9:27, mikes@flatsurface.com (Mike S) wrote:
>
>
>> At 12:00 PM 3/12/2011, Said Jackson wrote...
>>
>>> The average will approach 0.0 as the number of samples is increased, but not the standard deviation.. The value displayed by their unit is standard deviation.
>>>
>> If you're measuring jitter of an external signal, accuracy is obviously much worse than the internal jitter. But if you're measuring TI, both the instrument and signal jitter get reduced with more measurements, leaving a more accurate TI, doesn't it?
>>
>> Being designed and sold as a TI analyzer, that seems right. It seems the jitter test is mostly to make sure the unit is operating properly.
>>
>> If I recall correctly, internal jitter is affected by tweaking the 200 MHz multiplier. Lacking a proper spectrum analyzer, that's the only calibration I have been unable to do.
>>
>> _______________________________________________
>> 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.
>
>
