[time-nuts] Data collection cycle -- multiple sources to one counter?
Dr. David Kirkby
drkirkby at medphys.ucl.ac.uk
Mon Jun 20 08:31:35 EDT 2005
John Ackermann N8UR wrote:
> I want to monitor all my atomic devices over the long term against GPS.
> Rather than devoting one counter to each source and gathering a lot more
> data than is useful, I'm going to use a GPIB-controlled coax switch to
> route the 1pps from each source into the counter START input. That way
> I can alternately read each source for X minutes against GPS.
Just a thought (and probably a stupid one). Is the time delay through a PIN diode switch
sufficiently repeatable to allow such measurements, or would any changes of delay with temperature,
time etc mess up your measurements? Has anyone evaluated PIN diodes for this purpose? They would
certainly get around any worries of wearing them out, as there are no moving parts.
You can buy a 4-way single throw switch with SMA connectors for under $110 which has a minimum of 40
dB (typcally 60dB) isolation at 10MHz.
Dr. David Kirkby PhD CEng MIEE,
Senior Research Fellow,
Department of Medical Physics,
Mallet Place Engineering Building,
University College London,
London WC1E 6BT.
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