Building complete mbpsk modulator


#1

hello im a telecommunications engineering student and i cant build
complete
bpsk modulator, when i multiply the signal that returns of
gr_chunks_to_symbols_bc by the local oscillator the output signal its
wrong
and i dont know what can i do wrong
this is my code:

src = gr.file_source (1, ‘audio_1.dat’, False)

self.bytes2chunks=gr.packed_to_unpacked_bb(self.bits_per_baud(),
gr.GR_MSB_FIRST) #

self.chunks2symbols = gr.chunks_to_symbols_bc(psk.constellation[arity])

self.connect(src,self.bytes2chunks,self.chunks2symbols)

if_rate=48e3
lo_freq=2math.pi10

      # Local oscillator

lo = gr.sig_source_c (if_rate,gr.GR_COS_WAVE,lo_freq, 1.0, 0)

mixer = gr.multiply_cc ()

self.connect(self.chunks2symbols,(mixer,0))

self.connect(lo,(mixer,1))

dst = gr.file_sink (gr.sizeof_gr_complex,‘float.dat’)

self.connect(mixer,dst)
self.star()

maybe this code dont work god but is the essence
thanks for your atencion


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#2

I was trying to do a bpsk modulator on the similar line…what is the
flaw in the code