I am building a FSK receiver to recover data on UHF. The bit rate of the data
is 9,6kbps sent at 437MHz. I put all the information of the flowgraph.
The data sent are a Stream of 0x55 or in binar « 1010 ». the medium between the
emitter and the receiver is coax cable.
Here is my flowgraph on GRC : https://ibb.co/ixMYkn
I Use a bladeRF to record the signal. The Spectrum of the reception is the
following : https://ibb.co/gA6Nd7
As I can see the signal does not saturate the reception, then the signal should
To summarize my flowgraph :
- Multiply : to center of my signal
- Low pass filter : gross filter to have the signal
- Quadratur demod : demodulate the signal
- Low pass filter (decimation) : keep only the signal and decimate the sample
rate for the next block to 10 symbol per sample
- Clock recovery MM : find the clock
- Binary slicer : define 0 and 1
At the end of the flowgraph I save the data received in a file and here is the
result : https://ibb.co/dJyeQn
I have some holes in my file that I do not understand. I tried to use the
polyphase clock sync, I also changed the filter size, Nothing change.
Does anyone has an idea where my mistake is ? I am sure that my emitter send
the right data. If I miss information, tell me I will provide it/them. I also
can send the gnuradio flowgraph.
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