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

[Mike Markowski]

I can't make out details in your image, George, but attach one I made 
when working through the tutorial and works just now under gnuradio 
3.8.1.0.  Like someone else mentioned in another reply, I found the 
delay to be 58 and set it as the default in the attached flowgraph. 
Zoom in on the bit stream plot and allow a second or two after changing 
delay to see the effect.

Hope this helps,
Mike Markowski

On 3/12/21 10:37 AM, 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

mpsk_stage6.grc
Description: application/gnuradio-grc