[time-nuts] Re: time-nuts Digest, Vol 12, Issue 20

Tom Clark w3iwi at toad.net
Sun Jul 10 16:13:32 EDT 2005


>Today's Topics:
>
>   1. How do I measure oscillator frequency using 1pps? (David Kirkby)
>   2. Re: How do I measure oscillator frequency using 1pps?
>      (John Ackermann N8UR)
>   3. Re: How do I measure oscillator frequency using 1pps? (Javier)
>   4. Re: How do I measure oscillator frequency using 1pps?
>      (Brooke Clarke)
>   5. Re: How do I measure oscillator frequency using 1pps?
>      (Tom Van Baak)
>   6. Re: How do I measure oscillator frequency using 1pps? 
>      (Poul-Henning Kamp)
>   7. Axiom Sandpiper II (Mike Feher)
>   8. Re: How do I measure oscillator frequency using 1pps?
>      (Bill Janssen)
>
>  
>
I'd suggest you look at my "Timing for VLBI" tutorial at 
http://gpstime.com -- specifically fetch the latest 2005 version.

Also if you need to get a 10 MHz oscillator to make 1PPS pulses, I 
highly recommend the simple PIC-based divider developed by Tom Van Baak; 
I can't find it on Tom's leapsecond.com any more, but Brooks Shera has 
it at http://www.rt66.com/~shera/ppsdiv.zip 
<http://www.rt66.com/%7Eshera/ppsdiv.zip>. [Tom -- can you post where 
the master copy now resides?]

Finally, if you want more "why" detail, I recommend that everyone MUST 
have a copy of the old HP application note #1289, "the Science of 
Timekeeping" (of course the relevant divisions at HP are now part of 
Agilent). If you don't have a copy, I've posted it at 
http://mysite.verizon.net/w3iwi/hpan1289.pdf.  Also at that site is HP's 
1272 document "GPS and Precision Timing Applications" at 
http://mysite.verizon.net/w3iwi/hpan1272.pdf.

Tom Clark






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