#!/usr/bin/env python # # Weaver SSB demodulation # # # af_loi # | # --[lpf2i]---(X)---| # | af_mixi | # | | # signal --[freq xlating]--[split] (+)----- ssb_demod # [fir filter ] | | + USB # | af_mixq | - LSB # --[lpf2q]---(X)---| # | # af_loq # # This version uses TWO branches of the above, one for LSB and one for USB # and feeds to the right & left audio out for 'stereo' independant side band from gnuradio import gr, gru from gnuradio import audio from gnuradio import usrp def build_graph (freq,scale,usrp_center,audio_file,radio_file,input_file): # command line options if audio_file == "": SAVE_AUDIO_TO_FILE = False else: SAVE_AUDIO_TO_FILE = True if radio_file == "": SAVE_RADIO_TO_FILE = False else: SAVE_RADIO_TO_FILE = True if input_file == "": PLAY_FROM_USRP = True else: PLAY_FROM_USRP = False usrp_decim = 100 rf_sample_rate = 64000000 / usrp_decim af_sample_rate = 32000 fir_decimation = rf_sample_rate / af_sample_rate fg = gr.flow_graph () if PLAY_FROM_USRP: src = usrp.source_c(0,usrp_decim) mux = gru.hexint(0xf0f0f0f0) src.set_pga(0,20) src.set_mux(mux) src.set_rx_freq(0,-usrp_center) tune_offset = -usrp_center - src.rx_freq(0) else: src = gr.file_source (gr.sizeof_gr_complex,input_file) tune_offset = 2200 # 2200 works for 3.5-4Mhz band # save radio data to a file if SAVE_RADIO_TO_FILE: file = gr.file_sink(gr.sizeof_gr_complex, radio_file) fg.connect (src, file) rf_LO_L = usrp_center - ( freq - tune_offset ) + 1.8e3 rf_LO_U = usrp_center - ( freq - tune_offset ) - 1.82e3 af_LO = 1.8e3 xlate_taps = gr.firdes.low_pass ( \ 1.0, rf_sample_rate, 20e3, 10e3, gr.firdes.WIN_HAMMING ) # LSB branch xlate_L = gr.freq_xlating_fir_filter_ccf ( \ fir_decimation, xlate_taps, rf_LO_L, rf_sample_rate ) split_L = gr.complex_to_float () af_loi_L = gr.sig_source_f (af_sample_rate,gr.GR_COS_WAVE,af_LO,1,0) af_loq_L = gr.sig_source_f (af_sample_rate,gr.GR_SIN_WAVE,af_LO,1,0) lpf2_taps = gr.firdes.low_pass ( \ 1.0, af_sample_rate, 2e3, 600, gr.firdes.WIN_HAMMING) lpf2i_L = gr.fir_filter_fff (1, lpf2_taps) lpf2q_L = gr.fir_filter_fff (1, lpf2_taps) af_mixi_L = gr.multiply_ff () af_mixq_L = gr.multiply_ff () sum_L = gr.add_ff () # sub for USB, add for LSB audio_lpf_coeffs = gr.firdes.low_pass ( \ 1.0,af_sample_rate,3000,600,gr.firdes.WIN_HAMMING) audio_lpf_L = gr.fir_filter_fff (1, audio_lpf_coeffs) scale_L = gr.multiply_const_ff(scale) # USB branch xlate_U = gr.freq_xlating_fir_filter_ccf ( \ fir_decimation, xlate_taps, rf_LO_U, rf_sample_rate ) split_U = gr.complex_to_float () af_loi_U = gr.sig_source_f (af_sample_rate,gr.GR_COS_WAVE,af_LO,1,0) af_loq_U = gr.sig_source_f (af_sample_rate,gr.GR_SIN_WAVE,af_LO,1,0) lpf2i_U = gr.fir_filter_fff (1, lpf2_taps) lpf2q_U = gr.fir_filter_fff (1, lpf2_taps) af_mixi_U = gr.multiply_ff () af_mixq_U = gr.multiply_ff () sum_U = gr.sub_ff () # sub for USB, add for LSB audio_lpf_U = gr.fir_filter_fff (1, audio_lpf_coeffs) scale_U = gr.multiply_const_ff(scale) # AM branch mag = gr.complex_to_mag() sel_am = gr.multiply_const_ff(0) scale_am = gr.multiply_const_ff(0) # AGC lsb sqr1_L = gr.multiply_ff() int_L = gr.iir_filter_ffd ( [.004, 0], [0, .999] ) offset_L = gr.add_const_ff(1) agc_L = gr.divide_ff() # AGC usb sqr1_U = gr.multiply_ff() int_U = gr.iir_filter_ffd ( [.004, 0], [0, .999] ) offset_U = gr.add_const_ff(1) agc_U = gr.divide_ff() # sideband selection sel_lsb_0 = gr.multiply_const_ff(1) sel_lsb_1 = gr.multiply_const_ff(1) sel_usb_0 = gr.multiply_const_ff(0) sel_usb_1 = gr.multiply_const_ff(0) select0 = gr.add_ff() select1 = gr.add_ff() out = audio.sink (long(af_sample_rate)) fg.connect (src, xlate_L) fg.connect (src, xlate_U) fg.connect (xlate_L, split_L) fg.connect (xlate_U, split_U) fg.connect ((split_L, 0), lpf2i_L) fg.connect ((split_U, 0), lpf2i_U) fg.connect (lpf2i_L, (af_mixi_L, 0)) fg.connect (lpf2i_U, (af_mixi_U, 0)) fg.connect (af_loi_L, (af_mixi_L, 1)) fg.connect (af_loi_U, (af_mixi_U, 1)) fg.connect (af_mixi_L, (sum_L, 0)) fg.connect (af_mixi_U, (sum_U, 0)) fg.connect ((split_L, 1), lpf2q_L) fg.connect ((split_U, 1), lpf2q_U) fg.connect (lpf2q_L, (af_mixq_L, 0)) fg.connect (lpf2q_U, (af_mixq_U, 0)) fg.connect (af_loq_L, (af_mixq_L, 1)) fg.connect (af_loq_U, (af_mixq_U, 1)) fg.connect (af_mixq_L, (sum_L, 1)) fg.connect (af_mixq_U, (sum_U, 1)) fg.connect (sum_L, audio_lpf_L) fg.connect (sum_U, audio_lpf_U) fg.connect (audio_lpf_L, scale_L) fg.connect (audio_lpf_U, scale_U) # wire AGC fg.connect (scale_L, (sqr1_L, 0)) fg.connect (scale_U, (sqr1_U, 0)) fg.connect (scale_L, (sqr1_L, 1)) fg.connect (scale_U, (sqr1_U, 1)) fg.connect (sqr1_L, int_L) fg.connect (sqr1_U, int_U) fg.connect (int_L, offset_L) fg.connect (int_U, offset_U) fg.connect (offset_L, (agc_L, 1)) fg.connect (offset_U, (agc_U, 1)) fg.connect (scale_L, (agc_L, 0)) fg.connect (scale_U, (agc_U, 0)) # wire sideband selection fg.connect (agc_L, sel_lsb_0) fg.connect (agc_U, sel_usb_0) fg.connect (agc_L, sel_lsb_1) fg.connect (agc_U, sel_usb_1) fg.connect (sel_lsb_0, (select0, 0)) fg.connect (sel_usb_0, (select0, 1)) fg.connect (sel_lsb_1, (select1, 0)) fg.connect (sel_usb_1, (select1, 1)) fg.connect (select0, (out, 0)) fg.connect (select1, (out, 1)) # output to file if SAVE_AUDIO_TO_FILE: f_out = gr.file_sink(gr.sizeof_short,audio_file) # This creates a signed-word 2-channel (stereo) file at 32000 hz # convert to wav file with: sox -c 2 -r 32000 hfx_out.sw hfx_out.wav combine = gr.interleave(gr.sizeof_short) sc1 = gr.multiply_const_ff(64000) sc2 = gr.multiply_const_ff(64000) f2s1 = gr.float_to_short() f2s2 = gr.float_to_short() fg.connect (select0, sc1) fg.connect (select1, sc2) fg.connect (sc1, f2s1) fg.connect (sc2, f2s2) fg.connect (f2s1, (combine, 0)) fg.connect (f2s2, (combine, 1)) fg.connect (combine, f_out) # wire AM fg.connect (xlate_L, mag) fg.connect (mag, sel_am) fg.connect (sel_am, scale_am) fg.connect (scale_am, (select0, 2)) fg.connect (scale_am, (select1, 2)) return fg, tune_offset, xlate_L, xlate_U, scale_L, scale_U, src, audio_lpf_L, audio_lpf_U, sel_lsb_0, sel_lsb_1, sel_usb_0, sel_usb_1, sel_am, scale_am