[time-nuts] noise of a 5370

2011-03-12 Thread Jean-Louis Noel
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 impedance

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Geraldo Lino de Campos
Mine measure between 13 and 14 ps Date: Sat, 12 Mar 2011 11:26:48 +0100 > From: "Jean-Louis Noel" > To: "Discussion of precise time and frequency measurement" > > Subject: [time-nuts] noise of a 5370 > Message-ID: <2FD7B4DFC01B438A86E9675D1909B

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Mike S
At 05:26 AM 3/12/2011, Jean-Louis Noel wrote... 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? The manual says to expect jitter of 35 ps typical, 100 max. One of mine is ~30, the other ~20. ___

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Jean-Louis Noel
Hi Mike, From: "Mike S" 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 __

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Mike S
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 jitt

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Said Jackson
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, mi...@flatsurface.com (Mike S) wrote: > At 10:45 AM 3/12/2011, Jean-Louis N

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Mark Spencer
- Original Message From: Jean-Louis Noel To: Discussion of precise time and frequency measurement 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

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Mark Spencer
Mine shows approx 25 ps. - Original Message From: Jean-Louis Noel To: Discussion of precise time and frequency measurement 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

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Mike S
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 t

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Jean-Louis Noel
Hi Everyone, From: "Mark Spencer" 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 ___

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Robert Atkinson
Hi, My 5370B gives about 21ps Robert G8RPI. From: Jean-Louis Noel To: Discussion of precise time and frequency measurement 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

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Said Jackson
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

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Bruce Griffiths
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 whi

Re: [time-nuts] noise of a 5370

2011-03-12 Thread Mike S
At 09:51 PM 3/12/2011, Said Jackson wrote... Yes, the TI will get more accurate with time. But the setup suggested in previous email doesn't measure TI. No, it's basically one step of the self-testing steps in the manual. Measuring the jitter of the unit's own clock isn't particularly useful

Re: [time-nuts] noise of a 5370

2011-03-13 Thread Jean-Louis Noel
Hi, From: "Mike S" Measuring the jitter of the unit's own clock isn't particularly useful or interesting for anything other than checking for proper operation. I agree for the purpose, but the noise mesured is not only the clock noise. It's the sum of all noises. Not only the clock, 200MHz m