Thanks very much Christophe! George On Mon, Apr 19, 2021, 2:16 PM Christophe Seguinot < [email protected]> wrote:
> Hi > > comparing inp and out bits in x-PSK at least need differential > encoding/decoding, > > See for example > https://wiki.gnuradio.org/index.php/Guided_Tutorial_PSK_Demodulation > > > Regards, > On 19/04/2021 00:48, George Edwards wrote: > > Hello Gnuradio Community, > > I am working with the Gnuradio CCSDS 27 encoder/decoder blocks in Gnuradio > ver 3.8. To ensure I understand these blocks, I fed a random signal from > 0-255 into the encoder with an embedded Python block between the encoder > and decoder which converts the bit values 0 and 1 leaving the encoder into > -1 and +1 for the decoder. I use file sinks to collect the byte values > (between 0-255) entering the encoder and collect those leaving the decoder > and compare them to validate proper working functioning. Works good!!! > > Next, appropriate blocks comprising QPSK modulator/demodulator were > inserted between the CCSDS 27 encoder/decoder. At this point I could not > get the output of the decoder to equal to the input of the encoder. I have > tried everything, the latest being the decomposition of data (input and > output) down to the bit level and put in a delay to see if I can find > synchronization between the input and output bit values. I have attached my > grc flowgraph. > > I will appreciate any help. > > Regards, > George > >
