[Discuss-gnuradio] Two samples per symbol..how can we use both samples t
From:
Bishal Thapa
Subject:
[Discuss-gnuradio] Two samples per symbol..how can we use both samples to create a symbol during demod!!
Date:
Mon, 28 Sep 2009 23:16:16 -0400
Dear Thomas and Tim, Thank you for replying all my questions previously. I have another question for the list. Hope you don't mind. I wrote a demod for dbpsk. I had to because I am spreading/despreading packets using dbpsk modulation. DBPSK demod turned out pretty easy, except I committed a serious mistake that didn't take its toll until very much later. Since, gnuradio is collecting two samples per symbol, I hapazardly was skipping every other sample, and just using one sample per symbol to demodulate the dbpsk samples. This is obviously wrong, now I realize that a hard way. Could someone, a DSP being, or the gnuradio-dbpsk- demod developer help me understand, how can i combine both samples to decide on one symbol? I am doing a hack without understanding much. I am taking average of two samples and then using it to calculate phase difference with the next bit-sample. This is a hazard, I know :(. Please shed some light on these two samples per symbol business, please!!