Re: [Discuss-gnuradio] PSK modulation and demodulation from gnu radio tutorial.

Hello Atiqur,

The "PSK Demod" that you added into your flowgraph is deprecated, and is no longer supported. It is kept there for the backward-compatibility, but it is not guaranteed to work and will be removed in future. Also, that block does the synchronization and the equalization by itself, so you must remove the preceeding synchronization and equalization blocks if you actually want to use that (you shouldn't, though). Try other blocks, like a Constellation Decoder or a custom Python block.

Channel Model is used to "degrade" the signal (for simulation purposes). It will apply a FIR filter to the incoming signals to simulate the multipath environment. The taps are the filter taps used for that purpose. It is just a sequence of a few random non-zero numbers to simulate the multipath effect, and shouldn't really affect the functionality of the synchronizer and the equalizer blocks. A good equalizer will cancel out the effect of those channel taps. 

Regards,

Kyeong Su Shin

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보낸 사람: Md. Atiqur Rahman <atiq.r12@gmail.com> 대신 Discuss-gnuradio <discuss-gnuradio-bounces+ksshin=postech.ac.kr@gnu.org>
보낸 날짜: 2019년 6월 28일 금요일 오후 9:32:46
받는 사람: discuss-gnuradio@gnu.org
제목: [Discuss-gnuradio] PSK modulation and demodulation from gnu radio tutorial.

 

Hello Guys,

I am very much new in gnu radio and trying to do the tutorial that gnuradio published for PSK demodulation. I am using constellation modulator to modulate the signal and demodulate it by PSK demodulation block(not my QPSK demodulator). I did put every parameter as they suggested.  Unfortunately, I do not get the same result(synchronized input and output ). I think its may the Channel model or time recovary block is not set correctly. Moreover, I do not understand why they use the channel model taps parameter to [1.0, 0.25-0.25j, 0.50 + 0.10j, -0.3 + 0.2j]? How did the get that? I did already spend a lot of time for searching about these but do not get any specific understandable solution.

I attach my .grc file in this mail. Please have a look. Looking forward to hearing from you guys.

Sincerely,

Atiq