# Coding of 8psk signal in GNU radio and its decoding in Matlab

**URL:** <https://www.ruby-forum.com/t/coding-of-8psk-signal-in-gnu-radio-and-its-decoding-in-matlab/263872>\
**Category:** GNU Radio\
**Created:** [May 20, 2023, 12:41pm UTC](https://www.ruby-forum.com/t/coding-of-8psk-signal-in-gnu-radio-and-its-decoding-in-matlab/263872 "2023-05-20T12:41:46Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Frog](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/9fc29f/32.png) [@Frog](https://www.ruby-forum.com/u/Frog)\
**Post date:** [May 20, 2023, 12:41pm UTC](https://www.ruby-forum.com/t/coding-of-8psk-signal-in-gnu-radio-and-its-decoding-in-matlab/263872/1 "2023-05-20T12:41:46Z")

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I record an 8PSK signal using the following scheme (1):

 ![image](https://www.ruby-forum.com/uploads/default/original/2X/2/25261385fe3f6eb0d3edea36632c8fe1d9ac8ab6.png)  
After that, I open the recorded signals in Matlab and add them (signal = re + 1i\*Im):  
After that, I demodulate.The original signal differs from the demodulated one. For demod i use comm.PSKDemodulator (8, ‘BitOutput’,true)  
If I decode the signal in GNU radio, then the signals are the same.

Can you explain what the problem is and correct me?