[time-nuts] An (unknown?) nasty feature of the DDS principle for time nuts applications

pablo alvarez pabloalvarezsanchez at gmail.com
Fri Jan 28 13:47:22 UTC 2011


The AD9850 has a 10bit DAC. If the AD9850 does not dither the 10bit ADC
output the zero crossings for a 1MHz signal will have an aprox resolution of
2^-10*1us~1ns on average. If the lookup table feeding values to the dac has
10 address lines (just guessing, I do not see any anything on it on the
datasheet), you will have an additional uncertainty of 1ns to the phase
error. Adding these two we have the ~2ns Ulrich is measuring.

What do you think?


> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

More information about the time-nuts mailing list