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Sampled QPSK model.

Question asked by azp25 on Aug 17, 2005
Hello I ahve a simple QPSK model that I have enclosed. I have been staring at it for quite sometimes now but can seem to find out what is wrong.

The model modultes a signal to 153 MHz. I am resampling at 150 MHZ to shift the spectrum to 3 MHz. I use the filter - It is not needed here- But I intend to add channels at 156MHz, 159MHz, etc.

1- The demodulated Q side in inverted and I do not know why.
2- When I change the filter coeficent to a singned integers, it does not work at all.

I am having diffeculty adding the BER. But that is for next time.

Any help is greatly appreciated. :?: