OpenHT-fpga
OpenHT FPGA design - a complete Lattice Radiant project for the LIFCL-40-9SG72C.
Functionality
Generic modulators:
- frequency modulator
- amplitude modulator
- phase modulator
- single sideband (SSB)
- 16QAM (Gray-coded)
- arbitrary I/Q
- 32APSK
Generic demodulators:
- frequency demodulator
- amplitude demodulator
- phase demodulator
- single sideband (SSB)
- arbitrary constellation map
Other:
- I/Q raw sample access over SPI
- optional phase dither for the frequency/phase modulator
- Received Signal Strength Indicator (RSSI) estimation
- symbol recovery, clock sync
Supported modes
Analog: FM, AM, SSB, OOK (CW)
Digital: M17, FreeDV, crude "4FSK", SSTV, 16QAM, BPSK/QPSK/DQPSK, OFDM, AFSK, APRS
Note: automatic gain control (AGC) is done by the RF transceiver chip. Not all modes are yet implemented in the firmware.
Block diagram
Register map
The register map is listed in /docs/OpenHT_reg_map.pdf.
Gallery
Transmission
M17 (baseband via SPI)
SSB (USB) - FreeDV (baseband via SPI)
16QAM (unfiltered, internally generated, pseudorandom "staircase" baseband)
BPSK/QPSK (unfiltered, internally generated, pseudorandom "staircase" baseband)
Reception
M17
