Chris Albertson wrote:
Just got my fe5680 yesterday. Seems to work but the fe5680 is the most accurate reference I have. So how to test it? I plan to buy a Thunderbolt but until then, anyone have any creative ideas?
<snip>
Going to have to get a Thunderbolt. I have an Oncore UT+ the provides a good pulse per second but that will not help
You can take the FE-5680 10MHz and divide it down to a derived 1 PPS. Use the time interval measurement on your HP5328A to measure the TI between the Oncore 1 PPS (start) and the derived 1 PPS (stop).
You might want to set a finite TI (for example, 100 usec) by adjusting the phase of the derived 1 PPS so the measurement doesn't get confused.
I have done this using an HP5316B with good results.The jitter on the GPS 1 PPS might limit your short term resolution, but over a day or so you should be able to measure the drift of the FE-5680A.
I have used a Ref Tek 111A GPS clock for the 1 PPS. That unit has a lot (several usec) of jitter. I recently started using a 111C that has much lower jitter (a few 10's of nsec). I believe your OnCore unit will be similar.
Here are some results from my tracking my FE-5680A: http://c-c-i.com/image/tid/4 Most recent: http://c-c-i.com/node/159 Hope this helps. -- ======================================================================== Bob Smither, PhD Circuit Concepts, Inc. "Patriotism is supporting your country all the time, and your government when it deserves it." - Mark Twain smit...@c-c-i.com http://www.C-C-I.Com 281-331-2744 ========================================================================
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