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 E. 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

–

AMSAT VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats,

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