I have an HP Z3816A GPS timing receiver. It has 4 of its output connectors at 19.6608 MHz. I gather this was for cellular telephone service. Just curious... 19.6608 MHz seems like an unusual frequency. Is there some logical reason why that frequency was chosen for this application? I see this is 12C0000 in hex (or 300 * 65536). I guess this may be part of the reason. Would be pretty easy to divide down to 0.01 second intervals. I've been thinking of trying to hack the circuit board to convert the drive for these 4 outputs to also be at 10 MHz. I wonder if anyone else has already done this and could save me a lot of circuit tracing. -Rex

Hello, Not unusual at all. It is 4.9152 * 4 and also 6.5536 * 3, both quite common numbers :). It easily divides to standard serial baud rates (38400 * 16 * 32 ). Regards, Javier, EA1CRB Rex wrote: >I have an HP Z3816A GPS timing receiver. It has 4 of its output >connectors at 19.6608 MHz. I gather this was for cellular telephone >service. > >Just curious... 19.6608 MHz seems like an unusual frequency. Is there >some logical reason why that frequency was chosen for this application? >I see this is 12C0000 in hex (or 300 * 65536). I guess this may be part >of the reason. Would be pretty easy to divide down to 0.01 second >intervals. > >I've been thinking of trying to hack the circuit board to convert the >drive for these 4 outputs to also be at 10 MHz. I wonder if anyone else >has already done this and could save me a lot of circuit tracing. > >-Rex > > >_______________________________________________ >time-nuts mailing list >time-nuts@febo.com >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > >

In message <s2fr82hmko62cppbsa45tphgc3pl0l0g25@4ax.com>, Rex writes: >Just curious... 19.6608 MHz seems like an unusual frequency. Is there >some logical reason why that frequency was chosen for this application? It is the heartbeat of CDMA celluar networks as far as I know. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.