- #1
Jyan
- 36
- 2
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?
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?