Yes,this seems work.but the intention is get a radio.So, I use a USRP source instead FFT sink and observe in Spectrum Analyzer and it still doesn't work.
I think the only different is I use a usrp as CF to put baseband FM signal to RF because Spectrum Analyzer quite like FFT sink. 2009/10/28 Josh Blum <[email protected]> > My advice is to get this all figured out in software before using any > hardware (usrps and spectrum analyzers). > > You can simulate the effect of changing the max deviation all in software > using a noise source, throttle, nbfm tx block, and an fft sink (all in grc). > > I guarantee that changing max deviation from 5 to 50k makes a big > difference. > > -Josh > > nansai hu wrote: > >> I want to design a FM radio with freq deviation can be change. >> Then I tried to modified an example in GNUradio example folder which name >> "fm_tx4.py" in line61,let max_dev=5 to 50K,shown in following yellow >> label. >> but there is no change at all in a spectrum analyzer. >> Help me,thanks >> >> class pipeline(gr.hier_block2): >> def __init__(self, filename, lo_freq, audio_rate, if_rate): >> >> gr.hier_block2.__init__(self, "pipeline", >> gr.io_signature(0, 0, 0), >> # Input signature >> gr.io_signature(1, 1, >> gr.sizeof_gr_complex)) >> # Output signature >> >> src = gr.file_source (gr.sizeof_float,'/home/sdr/Desktop/hu/1.wma', >> True) >> fmtx = blks2.nbfm_tx (audio_rate, if_rate, max_dev=5, tau=75e-6) >> >> # Local oscillator >> lo = gr.sig_source_c (if_rate, # sample rate >> gr.GR_SIN_WAVE, # waveform type >> lo_freq, #frequency >> 1.0, # amplitude >> 0) # DC Offset >> mixer = gr.multiply_cc () >> >> self.connect (src, fmtx, (mixer, 0)) >> self.connect (lo, (mixer, 1)) >> self.connect (mixer, self) >> >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> [email protected] >> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >
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