I am working on a FMCW radar and I want to sample the I/Q signals from the 2 receiving antenna (total 4 channels) simultaneoulsy and send the digital data to computer to extract range and velocity information using FFT. The below diagram is a overall plan.
In the diagram I have shown a ADC with 1MSPS but thats not based on any calculation, just a rough idea as the maximum frequency component is 500kHz. To make it simplier and test for short range I planned to limit the frequency to 100 kHz.
Now my question is how should I senlect the sampling rate? I don't think 2*fmax (Sampling Theorem) is enough for this purpose. The output from the radar frontend are I/Q signals, band limited from 30Hz to 100kHz. My target is to digitize the signal to the best for proper analysis. Should I consider the DAC (used for tuning the frontend) sample number calculated from the minimum and maximum voltage for tuning, to calculate my sampling rate?