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

Attachment: phase_rotate.grc
Description: Binary data

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