[time-nuts] distribution amp question + hp 59309A

Tom Van Baak tvb at LeapSecond.com
Sat Jan 28 16:38:06 EST 2017

> Also on an unrelated topic, I found an HP 59309A HPIB clock on a forgotten shelf 
> and looked at it, and was surprised to see such a poor primary time standard 
> oscillator inside, just a 1Mhz crystal using a cmos buffer oscillator. It can 
> accept an external standard, but it did feel odd for a device that is meant to 
> provide coordinated system time to be so modestly executed.  it's like an 
> uncorrected PC desktop clock.


The hp 59503A was intended as a GPIB "system" time of day clock in the days before PC's had their own clocks, or before NTP or GPS existed. Imagine a 19" rack with 2 or 3 or 10 HP-IB instruments all on the same bus doing some complex experiment yet and no instrument knows the date or time-of-day that the data is collected, or maybe the controller needs to synchronize events across several instruments. Well, just add a 59503A and you're all set. It even has a battery backup option.

To their credit, and unlike a PC, there is an external frequency input, so you have control over the accuracy. It's a beautiful little instrument (lots of discussion in the archives).


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