[hpsdr] Penelope measurements

[Bill Tracey]

Hmm --not the result I'd expect for the GPSDO case.

One thing -- can you check you've got the latest version of 
Ozy_Janus.rbf -- the most recent has a size of 97282 and an md5sum 
of: 4e944865433c3176f4b9ade74140f1d3

Regards,

Bill  (kd5tfd)

At 10:29 AM 5/18/2008, Mark Amos wrote:
>***** High Performance Software Defined Radio Discussion List *****
>
>Folks,
>
>I did some more playing around with Penelope this weekend testing 
>the frequency of the transmitted output.
>Penelope had been powered up for about a half an hour. These were 
>tests run at 10.101000 MHz.
>
>I found that when I selected Penelope for the 10 MHz clock source 
>the transmit signal was low by 133 Hz
>(10.100867).  When I selected Atlas as the 10 MHz clock source 
>(using an an external GPSDO fed to pin C16 on
>the Atlas bus) the measured transmit frequency was about 24Hz high 
>at 10.100024.
>
>I expected it to be spot on. (A similar experiment with my SDR1000 
>showed the output to 10.101000 using the
>same GPSDO as with Penelope and same counter.)
>
>I believe the measurements to be accurate - I'm using an HP 5328A 
>counter with a GPSDO external clock that
>measures the GPSDO's to within 1 Hz at 10 MHz.  Also, when I zero 
>beat the GPSDO driving Penelope against 10
>MHz WWV with the SDR1000 and Ten Tec Orion it seems to be dead on 
>when it shows 10.000000 on the counter.
>
>So, I think there's something wrong with my expectations.  Shouldn't 
>the transmitted frequency be closer than
>2.4 PPM?
>
>Just to be certain that my question is not misunderstood - I'm not 
>complaining about this; I'm really just
>trying to learn something!
>
>Thanks in advance!
>
>Mark



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