FreeDV demodulator is a GNU Radio block wrapping the codec2 library freedv_api for receiving digital voice signals.
Input is a stream of modulated signal data. Output is voice audio.
- select one of the 9 signal formats. (depending upon modes enabled in the linked codec2 library)
'1600' Initial mode. 8 kHz in and out.
2400A Input rate 48 kHz
2400B Input rate 48 kHz
800XA Input rate = Output rate = 8 kHz
700C Input rate = Output rate = 8 kHz
700D Input rate = Output rate = 8 kHz
'2020' low-bitrate - input rate is 4 kHz, Output rate 8 kHz
- Squelch threshold
- Interleave frames
- Squelch Enable
This flowgraph can be found at 
- C++ files
- Header files
- Public header files
- Block definition