Hi Mike, Thanks for the explanation. As I do not own a "reciprocal" counter, I was unfamilar or had forgotten the issue you described. "Reciprocal" was the missing link !
Bill....WB6BNQ Mike Feher wrote: > Bill - > > Sorry if I was vague. I am assuming that the frequency read out is the > frequency in the display, and, not one over the bus. Regardless of the fact > that the counter is auto scaling or not, they can only display a fixed > number of digits. I am also assuming that these are reciprocal type of > counters. So, given a fixed time base, and a fixed number of digits, if the > delta f measured is above 10 MHz, then with a 11 digit display, you would > read 10,000,000.000 Hz plus the offset from that number. So, the observable > delta f would be at best in the 0.000 Hz range. Now, if the frequency > measured was slightly below 10 MHz, you would be able to display up to > 9,999,999.9999 Hz. I am not considering any averaging at this time, just > what is displayed. So, in this case you should be able to measure down to > 0.0000 Hz delta f. Hence my statement of the extra LSD being shown. This has > been my experience. Regards - Mike > > > > Mike B. Feher, N4FS > 89 Arnold Blvd. > Howell, NJ, 07731 > 732-886-5960 > > > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > Behalf Of WB6BNQ > Sent: Saturday, December 22, 2007 7:00 AM > To: Discussion of precise time and frequency measurement > Subject: [time-nuts] Counter display resolution > > Mike, > > Your statement about "counters" is rather general and misleading. You need > to > explain your comment better. > > For instance, are your referring to the input signal or did you mean having > the > internal reference frequency offset from a standard value ? All the > counters I > have do not "auto-scale" which is what it sounds like your counter is doing. > However, you do not mention the word "scaling" or "auto" in your statement. > > In all of my counters the digits displayed is what you get no matter what > frequency is being observed. There is no gain in resolution by being > slightly > lower then or any loss by being higher then some arbitrary point. > > For the sake of the less skilled that might be on the list -server, could > you > explain in more clear detail what you were eluding to ? > > Thank you ... Bill....WB6BNQ > > Mike Feher wrote: > > > Bob - > > > > With most counters, I have found that running them at slightly less than > 10 > > MHz gives you an extra displayed digit of resolution. If the "1" out of 10 > > MHz were to be displayed, it would take up one more digit in the MSD > > position, leaving you one less in the LSD position. Since the numbers are > so > > close anyway, if measuring for stability, I personally would prefer that > > extra digit in the LSD position. Regards - Mike > > > > > > > > Mike B. Feher, N4FS > > 89 Arnold Blvd. > > Howell, NJ, 07731 > > 732-886-5960 > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > > Behalf Of Robert E. Martinson > > Sent: Saturday, December 22, 2007 1:57 AM > > To: 'Discussion of precise time and frequency measurement' > > Subject: Re: [time-nuts] HP 5370B question > > > > I ran my 5370B for one hour, counting its own reference with a one second > > gate. The summary of the results are: > > > > min 9999999.99650 Hz > > max 9999999.99963 Hz > > avg 9999999.99796 Hz > > median 9999999.99787 Hz > > > > Per the manual's Performance Test 5 (page 4-12) the spec is +/- 0.005 Hz. > > It would be nice if my average was 10,000,000.000 HZ but?? From a > Time-nuts > > thread of several months ago, the adjustment for this result is very > touchy > > and it's likely you will make the result worse rather then better. Since > > mine is in spec, I'll leave it alone. > > > > I have sent the graphical & raw data to Corby, if anybody else is > interested > > please advise me of your email address. > > > > Regards, > > Bob Martinson, N1VQR > > > > -----Original Message----- > > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > > Behalf Of corby d dawson > > Sent: Wednesday, December 19, 2007 2:15 PM > > To: [email protected] > > Subject: [time-nuts] HP 5370B question > > > > Hi, > > > > Could a few of the 5370B owners connect the counters reference output to > > its counting input jack and with a 1 second gate let me know what the > > last 2 digits are doing? > > > > An earlier post implied that the last couple digits will wander around > > due to the way its designed. > > > > I'd like to know what a couple different counters show to see if that is > > indeed true! > > > > Thanks, > > > > Corby Dawson > > > > _______________________________________________ > > 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. > > _______________________________________________ > 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.
