[time-nuts] retry: PRS10 has spurious frequencies

Henk ten Pierick henk at deriesp.demon.nl
Sun Apr 29 14:12:40 EDT 2007


On Apr 25, 2007, at 23:38, Dave Brown wrote:

> Henk
> Do any of the spurious signals show on the SA with a search antenna
> (located in your lab environment)connected instead of the PRS10?
> DaveB


No, they are not. I can see spurious if and only if the PRS10 is  
powered. When I open the PRS10 and search with a loop antenna, then I  
see the whole spectrum up to 600MHz. Most of the power comes from the  
board with the micro which runs at 10MHz. I expect that there is a  
parasitic coupling of this micro 10MHz to the PRS10 output.  This can  
explain why the spurious level increases with frequency to higher  
than the spectrum analyzer noise level at say 500MHz. The micro slew  
rate can explain why it decreases again into the noise above 700MHz.  
The spurious is only there if the micro runs. It is not clear to me  
why I can see this spurious and other PRS10 owners can not. May be a  
different run or version of the PRS10. My PRS10 has serial 5099.

Henk




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