Re: [Discuss-gnuradio] QPSK Modulation and Demodulation Question

[Julian Arnold]

Hey,

I only have my phone available right now so I can’t really check but from what 
I can see, you got a little problem with your decimation factors.

Your initial sps (samples per symbol) is 4 and you reduce it to 2 sps in the 
clock recovery process (output sps = 2). However, in you equalizer you set sps 
again to 4 whereas it should be 2.

Hope this helps.
Cheers,
Julian

Julian Arnold, M.Sc

> On 7. Aug 2018, at 23:08, 梁帆 <address@hidden> wrote:
> 
> Hello All,
> 
> I am using the Gnuradio for two weeks. I am doing the Gnuradio tutorial 7 on 
> stage 5. There I used PSK demod to demodulate the signal. I do not know why 
> the output signals are different than input signal. This is the screenshot of 
> my blocks. Is that because my vector source influence the result or should I 
> use the My_Qpsk_demod block on tutorial 4.
> 
> Thanks
> Fan
> <Screenshot from 2018-08-07 15-06-50.png>
> <Screenshot from 2018-08-07 15-07-01.png>
> <Screenshot from 2018-08-07 15-07-07.png>
> <Screenshot from 2018-08-07 15-07-17.png>
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