Looing at the schematics quickly, it looks like 1 MHz. There is a clock failure circuit on that line.
-John ================= > Hi > > So now the question becomes: With only modest / reversible butchery, > what's > the slowest pulse train it will accept? > > 1 MHz is not to bad to generate. Something slower would still be easier > with > a computer. If 1 ms accuracy is "good enough" then driving it with > anything > over 10 KHz is kind of overkill. > > Bob > > -----Original Message----- > From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On > Behalf Of J. Forster > Sent: Friday, January 15, 2010 12:28 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Sidereal time > > The external input triggers logic (via a selectable divider). It would > easily go +/- 50% in frequency. > > Artek Media has the manual. > > > -John > > ============= > > >> Hi >> >> There may be a gotcha. >> >> If that HP box has their standard time base in it, your idea isn't going >> to >> work. The normal HP approach is to lock a local oscillator up to the >> incoming reference input. That way they can handle a bunch of different >> time >> base inputs without much bother. Their standard VCXO does not have >> enough >> range to lock to a reference 0.03% off frequency. >> >> Bob >> >> -----Original Message----- >> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On >> Behalf Of Brian Kirby >> Sent: Thursday, January 14, 2010 10:13 PM >> To: precise time >> Subject: [time-nuts] Sidereal time >> >> I would like to have an electronic clock to keep sidereal time. I am >> planning on using a HP 59309A, which can except an external clock of >> 1/5/10 Mhz. >> >> According to Wikipedia sidereal time is 23 hours 56 minutes and 4.091 >> seconds - a total of 86,164.091 seconds >> >> So 86,400 seconds for a normal "atomic defined" day divided by >> 86,164.091 = 1.002,737,903,89 >> >> If I set the 59309A to 10 Mhz external clock and dial a synthesizer up >> to 10.0273790, the unit should be able to keep sidereal time. >> >> Is my math and theory correct ? >> >> Brian - KD4FM >> >> _______________________________________________ >> 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. > > > > _______________________________________________ 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.