Hi So to do things the "same way", start your time measurement at something less than 1 ms and do the math to get to 1 second and beyond. One advantage over the frequency reading would be that you will know what math has been done. The math *does* very much matter....
Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Tom Van Baak Sent: Tuesday, October 02, 2012 9:39 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Best counter setting for ADEV? Azelio, In frequency average mode the 53132A makes something like 200,000 measurements per second, according to the manual. This is why the instrument does so well as a smoothed frequency counter. The resolution "gain" is some fraction of sqrt(200000), subject to the normal caveats like the need for independent samples. That's why these counters have reduced resolution when the input frequency is too close a multiple/fraction of the timebase. Details on this technique (used also in the Pendulum CNT-9x counters): "New frequency counting principle improves resolution" http://tycho.usno.navy.mil/ptti/ptti2005/paper67.pdf See also this fine presentation by Staffan Johansson: http://www.npl.co.uk/upload/pdf/20060209_t-f_johansson_1.pdf Or, google for: continuous time-stamping frequency counter /tvb ----- Original Message ----- From: "Azelio Boriani" <[email protected]> To: "Discussion of precise time and frequency measurement" <[email protected]> Sent: Tuesday, October 02, 2012 5:30 AM Subject: Re: [time-nuts] Best counter setting for ADEV? > Hmm, the frequency mode sigma is the same as the TI mode sigma for 200*tau. > That is if I take the sigma at 200*tau from the TI mode I have the same > figure of the frequency mode. Maybe the frequency mode 2 seconds sample > time uses 100 averages per second. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
