Hardware:
- MCP2036
How does it work:
- Teensy produces LO RX frequency on BCLK (pin 9) or MCLK (pin 11)
- MCP2036 mixes LO with RF coming from antenna --> direct conversion
- MCP amplifies and lowpass filters the IF signal
- Teensy ADC samples incoming IF signal with sample rate == IF * 4
- Software Oscillators cos & sin are used to produce I & Q signals and simultaneously translate the I & Q signals to audio baseband
- I & Q are filtered by phase-added Hilbert FIR bandpass (for SSB) or FIR lowpass filters (AM)
- Demodulation --> SSB, AM
- Decoding of time signals or other digital modes [tbd]
- IIR biquad filter to shape baseband audio
- Audio output through Teensy DAC