USB-6351 minimum analog output resolution?

[Mike_TheKraken]

I'm using a USB-6351 to generate a SE analog output sine wave. The generated frequency range can range from 10KHz to 100KHz. Experimentally I've confirmed with 2 frequency counters, I am getting ~ 2 Hz resolution. The master clock for the system has a 100MHz clock. The DAQ output sample frequency is 2MHz, but I cannot figure out how to calculate the minimum frequency resolution from those parameters. I'd like to theoretically calculate if I can get 10,000 and 10,002, 10,004, etc, from system parameters, so I have an idea what is actually going on...

I was referenced to the below knowledgebase, but with it I don't get agreement with experiment.. It would insist on ~1KHz resolution, not 2 Hz.

Frequency Resolution of the Analog Output of a DAQ Device

http://digital.ni.com/public.nsf/allkb/C9F181974B734CAE862569F40050BE53

[Kevin_Price]

You've got several distinct parameters to keep track of.  One is the AO Update Rate clock frequency, which must be an integer divisor of the 100MHz master timebase clock on your board.  Another is your AO waveform buffer, which must contain an integer # of AO samples.  Further, in addition to the timing resolution of your samples, you probably also care about the amplitude resolution.  This desired amplitude resolution will put an additional constraint on the minimum # of AO samples you want per cycle.  Finally, of course, these things must all work together to produce your sine wave at the desired frequency, with sufficient amplitude resolution.

If only someone had been down this road before and made a vi to figure it all out...

(And, by the way, hid it away in a thread that probably won't show up for the most likely keyword searches)

Seriously though, read the linked thread and maybe this one too.  The key concept is that by defining the AO output buffer to contain multiple cycles of a repeating waveform, you can get almost arbitrarily good waveform frequency precision.

-Kevin P