I would like to configure the DAC to convert sample data which is stored in RAM on the ML605 and I'd like to loop that analog signal back into another ADC as a means to stimulate my signal processing chain. It appears that there are both an analog reconstruction filter as well as AC coupling on the output. Is it possible to configure the FMC150 for DC-coupled output? If so, what should be done here?
Also, I'd like to change the sampling clock to 80MHz for the ADC/DACs. Is it possible to modify the existing clock tree to provide 80MHz, or do I need to provide an external clock? If an external clock is required, what are the specifications (square vs. sinusoid, p-p voltage, AC/DC coupled)? Do the VCXO/PLL/etc. need to be disabled?
We gave up on trying to operate this board at anything other than its native 245.76Ms/s. Instead, we slave the associated circuits in our FPGA to the FMC150. We upconvert and downconvert to a low IF to get around the inherent high pass characteristic of the ac coupling.