[hpsdr] Penelope measurements

[Mark Amos]

Bill, 

Thanks for the suggestion.  Yes, I do have the version with the md5sum, below.

I certainly can't discount the possibility that I'm doing something wrong in setup or measurement - but I 
can't think of how I could cause such a discrepancy.

I'll keep looking.

Mark


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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