Posts: 1
Registered: ‎08-09-2012

Coarse Mixer function of DAC3283 not working properly on FMC150

There seems to be a problem with the Course Mixer function of the DAC3283.

I have developed my own project based on the Avnet DUC/DDC Reference design for the ML605/FMC150.

I sent a 12.5 MHz sine wave sampled at 62.5 MHz to the DAC. I have both FIR0 and FIR1 enabled. 
When I have the course_mixer(1:0) register set to 00 (normal mode), I see the 12.5 MHz tone on the spectrum analyzer as expected.
When I set the course_mixer(1:0) register to 01 (fs/2 mode), I expect to see that 12.5 MHz signal shifted up by fs/2 which would be:
12.5 MHz + 31.25 MHz = 43.75 MHz.

I am not getting a 43.75 MHz signal out of the DAC with this setup. Is there any special steps other than what I described above that I need to do to get this to work?

If I am not understanding the function of the course mixer, please correct me.