I am currently working on a product(cant disclose too much details of the actual project) in which some data is being sent via audible(but on the higher freq) sound that is encoded with dqpsk.
However, it gets very inaccurate at times since the receiver and the broadcaster does not have the same sampling windows. I am not trained academically for DSP and therefore having a lot of problem finding out what are the correct terms to search for.
Basically after a lot of debugging and simulation, i found that the most major issue is that the phase information gets more and more inaccurate as the output and the input gets more out of sync... Are there some techniques to find the beginning of the actual signal in the samples? The data isnt contained in just one sample window(they can span through quite a lot of windows)
Thanks! (I would appreciate any sort of help, even if it is just some term i should use to search on google... )
And on a seperate note, when the timing is relatively accurate, I am already able to get the data properly decoded, so I am not really having much problem with the psk side