#!/usr/bin/env python # # # Copyright 2005 Free Software Foundation, Inc. # # This file is part of GNU Radio # # GNU Radio is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2, or (at your option) # any later version. # # GNU Radio is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with GNU Radio; see the file COPYING. If not, write to # the Free Software Foundation, Inc., 59 Temple Place - Suite 330, # Boston, MA 02111-1307, USA. # ===================================================================== # 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 from gnuradio import audio def build_graph (freq,scale,usrp_center,tune_offset): usrp_decim = 100 rf_sample_rate = 64000000 / usrp_decim af_sample_rate = 32000 fir_decimation = rf_sample_rate / af_sample_rate rf_LO_L = usrp_center - ( freq - tune_offset ) + 1.8e3 rf_LO_U = usrp_center - ( freq - tune_offset ) - 1.82e3 af_LO = 1.8e3 fg = gr.flow_graph () src = gr.file_source (gr.sizeof_gr_complex,"/root/radio/ssb_data-3.8e6-c-d100_3-6-2005_6-35pm",1) 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) # 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 = gr.file_sink (gr.sizeof_float, "ssb_demod") 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)) fg.start() return fg, 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