I have been working with Gnuradio and USRP N200 for about a month now and about all this time I have never succeeded in transmitting digital voice via USRP. My Proposed approach is like
audio source--->CVSD encoder---->OFDM mod------>rational resample to 200k------->multiply with signal source (100k)------>USRP sink
on the receiver side
USRP source------> multiply with signal source (100k)----------..rational resample to 48k ------->low pass filter----->OFDM demod------>CVSD decoder ------->audio sink
I have also used a built in flowgraph of OFDM voice attached within where i get zero output with encoder (codec 2). If the encoder is disabled, the output works just fine. Any kind of assistance in this regard would be much appreciated.
OFDM_voice.grc