I am trying to model an FPGA FM radio demodulator in Python. I will have a mixer that converts an FM channel to 36MHz IF, and I plan on undersampling this IF signal. If in the digital world (my Python model), I have a high sample rate FM signal at 1.2MHz, should I be able to resample to a lower sample rate (after using a BPF ofc) and obtain the same aliasing down to baseband? My understanding is that this should be possible, it just doesn't seem to be working. I am confident I understand undersampling 100%, but am not so sure about resampling... When I resample the FM modulated signal I get complete garbage at the baseband. My high sample rate is 3MSPs, the FM signal is sitting with 200KHz bandwidth and a centre at 1.2MHz. I am resampling to 525KSPs, if this were undersampling then the FM signal would be sitting in the 5th nyquist zone. But does it work the same digitally?