01-28-2021, 10:08 AM
We have been trying to check if M17 can be implemented on MD380-class radios. Many thanks to the OpenRTX team for helping us with that one.
Let me list all unsolved mysteries and some other problems.
- There's no microphone audio signal present at the microcontroller (ADC)
- PC8 pin, that's probably configured as a PWM, is lowpassed and fed into speaker amp - is that enough to get speech out?
- 2-point modulation is done by the HR_C5000 chip. We can only try and set offsets at both outputs by writing to specific registers. That in turn allows us to swing MOD1 and MOD2 only by about 850 mV. Is that enough to get M17 RF out?
- How to get demodulated data?
Let me list all unsolved mysteries and some other problems.
- There's no microphone audio signal present at the microcontroller (ADC)
- PC8 pin, that's probably configured as a PWM, is lowpassed and fed into speaker amp - is that enough to get speech out?
- 2-point modulation is done by the HR_C5000 chip. We can only try and set offsets at both outputs by writing to specific registers. That in turn allows us to swing MOD1 and MOD2 only by about 850 mV. Is that enough to get M17 RF out?
- How to get demodulated data?