[Discuss-gnuradio] packer_decoder block in the GRC

[intermilan]

Hi:
       I recently used the GRC to test my Pi/4 DQPSK modulation and demodulation block.But and my
flow graph is vector_source->packet_encoder->pi/4 dqpsk mod->mutily_const->usrp_sink, usrp_source->
pi/4 dqpsk demod->packet_decoder->file_sink.but in my file_sink I got nothing.It seem that there is no
data output the packet_decoder.then I change the modulator to DQPSK,but there is still nothing output the
packder_decoder block. And I confirm that there is data input the packer_decoder block.Why did it happen?


Inter.