El 28/01/2012 00:17, [email protected] escribió:
Hello John,
thanks for maintaining the 5680A FAQ;
regarding its
frequency resolution, have you checked the DDS FSELECT pin (and maybe
also PSEL0/1) to see if they are doing some kind of "dithering" of the
DDS frequency ?
I've just checked it... yes, it does. In the unit I've at hand, a quick
check shows a square wave at FSELECT, rate 416.6666666...Hz, duty cycle
50% (exact as per a fast check, will try to measure with higher detail
later).
I've not reprogrammed the frequency adjustment on this unit, so I
suspect that the adjustment is done by a combination of varying the duty
cycle at FSELECT and reprogramming the DDS. Next step: to snif the SPI
buts to the AD9832 :)
Regards,
Javier
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
