I'm trying to demodulate a radio signal from Motorol DP4801 (MOTOTRBO) that follows DMR specification.
I'm receiving the signal by using HackRF with the rate sample 1 MHz. The radio uses frequency 406MHz. According to the standard DMR uses 4FSK modulation with the following deviations:
Symbol +3 - +1,944 kHz
Symbol +1 - +0,648 kHz
Symbol -1 - -0,648 kHz
Symbol -3 - -1,944 kHz
The RF carrier bandwidth is 12,5 kHz.
Because after the sampling the radio signal I've lost the original signal (406 MHz) I can't understand how I should set up bandpass filters to catch these deviations. I need it because I'm going to apply non-coherent FSK demodulation but as in the image but for 4 symbols.