DAC with THDB-ADA on DE2-115

I don't know much about OFDM. As far as I know, it's a system using many sub-carriers to transmit digital information. In case of that, I dont think it is impossible to get multiple frequency signals onto processing by that daughter board. However, the frequency for a carrier using DE2-115 for that ADC abd DAC, in my opinion, are, should be less than 6MHz to create a good waveform.

Here is a trick that I found myself (I'm sure there are at least 1 more using OBUF) that will be useful for you to deal with ADC and DAC on that board.

First, you create 2 25MHz clock by detectting the rising edge and falling edge of your main clock, like:

If risingedge, clockR = not clockR

If fallingedge, clockF = not clockF

Then use your clockF to drive the DAC clocks, Write signals, using clockR to drive ADC and the whole program. This is to avoid the clock skew when sometimes ADC samples first and DAC samples later, and vice versa (try to imagine here, I'm not cery good in explaining, try me if you dont understand)

Then, I'm sure your waveform will get no any distortion (if the output is clocked in your program)

Cheers,

Tan