Re: [Discuss-gnuradio] OFDM demodulation problem / example video

[Robert McGwier]

Jens:

This  pi/4-DQPSK.   That means

New-symbol  *  (complex conjugate (Old-symbol)) is   pi/4 modulo pi/2.  
Are you taking this into account on both the transmitter and the 
receiver and it in all of the bins before your inverse fft provides the 
time domain signal to transmit would be my best best.

I will look at it more carefully today if I have time but this question 
would be the first one I would ask the code to tell me.

Bob



Jens Elsner wrote:
> Here is my little problem in animated frames.
>
> What you are seeing is already DQPSK. Displayed is the signal
> constellation for one OFDM frame, 75 symbols. The code was posted earlier.
>
> The problem: The (differential!) signal constellation has a constant phase 
> offset for each OFDM symbol. Why? What to do about it?
>
> Jens
>   

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