DQPSK

[MarkI]

Do you differentially encode the data and then do serial to parrallel conversion? or the other way round for differential QPSK?

The DBPSK article on the website is useful but i wasn't sure if you duplicate the process for both channels seperately. This would make some sense as then you could work out if one of the channels was inverted.

I have implemented it by differentially encoding the bit stream and then doing serial to parrallel conversion. but then i need a way to demodulate the signal. possibly non-coherently. or to do it coherently i need to implement a costas loop. is coherent demodulation DEQPSK though?

Also when mixing up the carrier in hardware to a higher frequency does it invert the spectrum or transpose the data? as i am communicating with another type of modem and i seem to get inverted data.

Any help would be appreciated.

Regards

Mark ([e-mail])

[marki]

the post above is mine by the way