* 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
The AX.25 decoder is now decoding the received frames.
Also, the module now provides a UDP message source block. This block
will be responsible to receive UDP packets and transform them into PMT
messages for further processing in the GNU Radio flowgraph. As the
communication with the satnogs-client will be done in the same host, we
do not have to care about packet loss.
Furthermore, the module now provides and a debug message source block
for easy debugging.
The Morse decoding block has now the configuration parameter that
enables an automatic estimation of the dot duration. Based on this
estimation all other symbol durations are computed.
The CW decoder was wrongly producing a Short Pause symbol instead of a
dot symbol. With this fix the decoder can now reconstruct the initial
text sequence sent.
Also the CW matched filter now can directly produce the power of the
filtered samples. This is very handy in order to get rid off an
additional multiply block, saving vital resources especially for
embedded platforms.
For testing and demonstration purposes the morse_decoding_flowgraph can
be used. The word sequence is the `HELLO WORLD`.
The AGC block in the Morse decoding flowgraph is placed now at the
proper position. The output of the matched filter produces now a clear
and distinguishable signal during the presence of a pulse. This makes
the work for the signal to symbol decoder more easy.
The CW symbol decoder block takes as input the power of the processed
signal and tries to identify the dot and dash symbols. It produces
asynchronous messages containing the decoded symbols. The output
messages can be directly used by the Morse code decoder block, in order
to retrieve the clear text message.
There are some few thing that need to be done for the block to be fully
operational.
For now the generic clear text message sink just prints the decoded
clear text messages in the stdout. In the future and depending the needs
of the project, the clear text messages can be forwarded at other
services on the same host or via the network.
Also the debug message source block now supports injection of artificial
errors, for more robust decoding of the Morse decoder block.
Now, with the Morse code debug source block the testing of the decoder
can begin.
Add at the examples directory a small flowgraph that connects the debug
source block with the decoder.
Manolis Surligas
Nikos Karamolegkos
Manolis Surligas