This commit includes a blind frequency correction mechanism for FM
signals. It uses the information of the angle difference between two
concecutive samples and a VCO to continuously compenstate any frequency
offset. To avoid intermodulations, a low pass filter is used trying to
pass only the DC component that is needed.
* Set all decoders output to binary format
* Introduce the quadrature demodulation filter in all affected
flowgraphs, in order to reduce false alarms and increase performance
There are cases where in AFSK1200 mode, the transmit source uses the
G3RUH scrambling. Now the flowgraph implements both scrambled and
unscrambled decoders, so there is no need to descriminate between
scrambled and unscrambled satellites.
* Decoded frames are stored only in hex files
* Output only the CRC valid frames. For now, in order to get the CRC
failed manual edit of the flowgraph is needed. In the near future, a
command line arguemnt will enable/disable
* Fix clock recovery issue on AFSK 1200 decoder
* Improve performance of AFSK 1200
* Make AFSK 1200 decoder to produce waterfall and audio file with the
same characteristics as the generic FM demodulator flowgraph for a
unified output experience in the SatNOGS network
* AFSK1200 decoder with AX.25 frame support
* Fix issue with the AX.25 decoder when the frame has only one AX.25
SYNC flag
* Fix clear text debug output to print each one of the characters and
not the string, so that the payload can be partially be printed even if
it contains non-printable characters
* Add AFSK1200 decoder example that can decode frames from an .ogg file
retrieved by the satnogs-network
Manolis Surligas
Corey Shields
Nikos Karamolegkos