discuss-gnuradio
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Combined constellation modulator/Decoder do not seem to work


From: George Edwards
Subject: Re: Combined constellation modulator/Decoder do not seem to work
Date: Fri, 12 Mar 2021 16:00:52 -0600

Hi Christophe,

Thanks for sending your grc. I will check it (I have both Gnuradio versions 3.7.13.4 and 3.8) to see if I can glean some understanding from how you are setting parameters. 

I have attached my grc file, it is version 3.7.13.4. If you have the time, please glance at it to see if you can determine what is wrong. I am not worried about the delay between the two streams of data because I am dumping them into 2-  binary file sinks and comparing them after the fact in Jupyter Notebook. The problem is that the tx and rx data are not the same, so I must be missing some understanding in parameter settings.

Thanks again for the help!

Regards,
George

On Fri, Mar 12, 2021 at 12:00 PM Christophe Seguinot <christophe.seguinot@orange.fr> wrote:

This flowgraph (derived from the original mpsk_stage6.grc, I don't remember what I change) is working at least whitout impairments.

On 12/03/2021 16:37, George Edwards wrote:
Hello, 

I cannot get the combined Constellation Modulator/Decoder as shown below to work. The figure below is an example from the online Guided Tutorial PSK Demodulation.... I leave out the Equalizer, Costas Loop blocks, the channel was set to pass the signal unimpaired and the Poly Clock Sync was set for Output sps=1. The constellation plot of the output of the Poly Clock Sync is perfect. Now, in the flowgraph below, the signal entering the Constellation Modulator and that leaving the Constellation Decoder are routed into Time Sinks for display. I route these signals into File Sinks so I can print them and compare 1's and 0's. The results show they are not the same. I passed Constellation Rect.Object parameters to both the Constellation Modulator and Decoder, which seems logical to me, but I could be wrong???
Will appreciate any help you can provide because what enters the modulator should be the same as what is leaving the demodulator. 
Regards, 
George

image.png

Attachment: qpskModDem.grc
Description: Binary data


reply via email to

[Prev in Thread] Current Thread [Next in Thread]