[time-nuts] HP5061B Versus HP5071 Cesium Line Frequencies

Tom Van Baak tvb at LeapSecond.com
Fri Jun 2 19:28:36 EDT 2017

> A guy by the name of David W. Allan used direct multiplication to
> build NBS-4 and NBS-5, see http://tf.nist.gov/general/pdf/65.pdf .  He
> didn't see anything wrong with it.  He used a commercial frequency
> standard modified from 5 mc to 5.006880 mc.

That kind of LO is ok for a research clock. But maybe not so good for a working institutional or house standard where people expect frequency distribution in nice round numbers like 5 or 10 or 100 MHz.

The good news is that you can get a perfect 1PPS out of it: divide by 5006880 = 2^5 * 3^3 * 5 * 19 * 61. I've heard JohnA has one of these vintage 5.006880 mc oscillators so I did a PIC divider for him. See pd21 under www.leapsecond.com/pic/src/


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