I am a bit confused to the answer given for the following question.
The question reads as follows:
If the input to a binary differential PSK modulation system is 01100101000111 tabulate The differential coder output
I know that for the differential coder output: 0 is encoded by the same pulse used to encode the previous data bit and 1 is encoded by the negative(opposite) of the pulse used to encode the previous data bit.
I am confused because Online and what I calculated does not match the answer that my professor gave.
My answer: For 01100101000111 input --> the output 001000110000101
Professors answer: --> 1 -1 -1 -1 1 -1 -1 1 1 -1 1 -1 -1 -1 -1
I found that this is only true if I first invert the input then apply the method, (in other words For 01100101000111 input becomes 10011010111000 )
Im so confused now, because I do not think that is how he obtained his final answer.