Robert Roberts wrote: > Hello everyone, > > > I have been experimenting with the Flex400 board and have been trying to > implement a basic AM transmitter. I have a WFM and NFM transmitter > working, but I cannot get the AM one to transmit correctly. The code > below generates a much higher frequency tone. Any advice to what I am > doing wrong? Does my output need filtering before connecting to the > sink? > > > self.u = usrp.sink_c () # the USRP sink > > # Code here for setting up the USRP, omitted > > src = gr.file_source (gr.sizeof_float, "audio-1.dat", True) # 440Hz tone > file What is the sample_rate of the audio file What is you interpolation rate of the usrp What is the duc frequency of your usrp. If the sample rate of your audio file is for example 48000 Herz Then the usrp interpolation rate should be 128000000/48000 = 2666 Which is I think way out of range for the usrp You first have to interpolate in software to something in the range of the usrp.
Greetings, Martin > const = gr.add_const_ff (1.0) > conv = gr.float_to_complex() > > > gain = gr.multiply_const_cc (4000.0) # transmitter gain > > # connect it all > > self.connect (src, const) > self.connect (const, conv) > self.connect (conv, gain) > self.connect (gain, self.u) > > > > > Thanks, > ~Chris~ > > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
