[time-nuts] AD9912 DDS frequency resolution measurement?

[Bo Hansen]

Hi

I have experience with the AD9912 in this H/W and S/W implementation: <http://rudius.net/oz2m//ngnb/dds.htm>

But I must admit that I personally haven't measured the minimum frequency step size. Poul-Henning Kamp, among others, is using one of the AD9912 DDS units and observed a similar error, I think, that he has solved in this S/W: <http://phk.freebsd.dk/misc/ftw.c>

Whatever applies list the FTW values and calculate back to the real frequency and see if the frequency change is correct.

A friend of mine has a x96 multiplier from 108 MHz to 10 GHz but we don't have access to any counters capable if measuring the difference.

Bo