Hi BobI didn't expect something to be tunable in the counter (except for the oscillator) - what is it that has to be calibrated?
Thanks Volker Am 03.11.2012 18:04, schrieb Bob Camp:
Hi The 620 is still pretty good (when tuned up). It certainly beats the Pendulum's on a single shot basis. The 53230 is spec'd to be as good as the 620. I suspect it meets or exceeds it's stated specs. Bob On Nov 3, 2012, at 12:58 PM, Tom Knox<act...@hotmail.com> wrote:Hi Magnus; I hope this is not to far off thread. Has anyone in the group done real world measurements of single shot res, and jitter on the new Agilent and Tektronix/Pendulum counters compared to the SR620 and Agilent 53132A. I would imagine that counter designs would be an area that really benefits from ongoing advances in digital technology. I have also found that it is much easier to claim specs then meet specs. Thanks; Thomas KnoxDate: Sat, 3 Nov 2012 16:28:42 +0100 From: mag...@rubidium.dyndns.org To: time-nuts@febo.com Subject: Re: [time-nuts] A counter for phase measures On 11/03/2012 03:10 PM, Volker Esper wrote:Thank you for the interesting information. Now, the time has come to look for an adequate counter - anyone who has experience with the HP 53132A and the SR620? If they both where at - say 1000 USD - what would you prefer for the job of phase measurement? I've read about that massive single shot capability of the SR, but - as being a newbie - is there anything I overlook at this moment?For short time-scales, single shot resolution and trigger jitter dominates your measurement floor. Single-shot resolution is the time resolution by which you make a single measurement. Trigger jitter is the noise at the trigger point. it's a combination of thermal noise and the slew-rate at the trigger points. It is often that trigger jitter is dominated by slew-rate, but there is also internal sources of trigger jitter. The slope dependent trigger jitter follows the formula: t_jitter = v_noise / s_slew t_jitter is the trigger jitter (s) v_noise is the noise power (V) s_slew is the slew rate (V/s) When the time-span of a measurement is long, long-term stability comes in as well as systematic drifts. Also, systematic noise such as hum also becomes important. To see how much you depend on slew-rate limitation, you can reduce the amplitude, and as this reduces the slew-rate you can separate the slew-rate dependent jitter from the intrinsic jitter of the input. It also helps you to identify if you need to work on the slew-rate limit rather than anything else. So, it may not be the single-shot resolution which limits you, but a combination of things. I would recommend you to pick up a SR620. It has 4 ps single shot resolution and about 25 ps jitter (but you can get less). That is significantly better than the 53152A provides. SR620 manual (one of many links): http://ilrs.gsfc.nasa.gov/docs/timing/sr620_manual.pdf Cheers, Magnus _______________________________________________ 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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
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