| #!/usr/bin/env python |
| ################################################## |
| # Gnuradio Python Flow Graph |
| # Title: GSM wideband input adaptor |
| # Author: Piotr Krysik |
| # Co-author: Pieter Robyns |
| # Description: Adaptor of input stream for the GSM receiver. Contains frequency ofset corrector doing also resampling to integer multiplies of GSM sample rate and LP filter filtering GSM channel. |
| ################################################## |
| |
| from gnuradio import filter |
| from gnuradio import gr |
| from gnuradio import eng_notation |
| from gnuradio.filter import firdes |
| import grgsm.arfcn as arfcn |
| import grgsm |
| |
| class gsm_wideband_input(grgsm.hier_block): |
| def __init__(self, ppm=0, osr=4, fc=925.2e6, samp_rate_in=20e6, ca=[], band='P-GSM'): |
| self.num_streams = len(ca) |
| grgsm.hier_block.__init__( |
| self, "GSM wideband input adaptor", |
| gr.io_signature(1, 1, gr.sizeof_gr_complex*1), |
| gr.io_signature(self.num_streams, self.num_streams, gr.sizeof_gr_complex*1), |
| ) |
| |
| ################################################## |
| # Parameters |
| ################################################## |
| self.ppm = ppm |
| self.osr = osr |
| self.fc = fc |
| self.samp_rate_in = samp_rate_in |
| self.ca = ca |
| self.blocks_fir_filters = {} |
| self.blocks_resamplers = {} |
| self.blocks_ocs = {} |
| self.band = band |
| |
| ################################################## |
| # Variables |
| ################################################## |
| self.samp_rate_out = samp_rate_out = 1625000.0/6.0*osr |
| |
| ################################################## |
| # Blocks |
| ################################################## |
| self.ppm_in = None |
| self.message_port_register_hier_in("ppm_in") |
| #self.lpf = firdes.low_pass(1, samp_rate_out, 125e3, 5e3, firdes.WIN_HAMMING, 6.76) |
| self.lpf = firdes.low_pass(1, samp_rate_in, 125e3, 75e3, firdes.WIN_HAMMING, 6.76) |
| self.gsm_clock_offset_corrector_0 = grgsm.clock_offset_corrector( |
| fc=fc, |
| ppm=ppm, |
| samp_rate_in=samp_rate_in, |
| ) |
| |
| center_arfcn = arfcn.downlink2arfcn(fc, band) |
| fc_str = eng_notation.num_to_str(fc) |
| print("Extracting channels %s, given center frequency at %sHz (ARFCN %d)" % (str(ca), fc_str, center_arfcn)) |
| |
| self.connect((self, 0), (self.gsm_clock_offset_corrector_0, 0)) |
| |
| output_port = 0 |
| for channel in ca: |
| channel_freq = arfcn.arfcn2downlink(channel, band) |
| if channel_freq is None: |
| print("Warning: invalid ARFCN %d for band %s" % (channel, band)) |
| continue |
| freq_diff = channel_freq - fc |
| freq_diff_str = "+" if 0 <= freq_diff else "" |
| freq_diff_str += eng_notation.num_to_str(freq_diff) |
| print("ARFCN %d is at %sHz %sHz" % (channel, fc_str, freq_diff_str)) |
| |
| self.blocks_resamplers[channel] = filter.fractional_resampler_cc(0, samp_rate_in/samp_rate_out) |
| self.blocks_fir_filters[channel] = filter.freq_xlating_fir_filter_ccc(1, self.lpf, freq_diff, samp_rate_in) |
| self.connect((self.gsm_clock_offset_corrector_0, 0), (self.blocks_fir_filters[channel], 0)) |
| self.connect((self.blocks_fir_filters[channel], 0), (self.blocks_resamplers[channel], 0)) |
| self.connect((self.blocks_resamplers[channel], 0), (self, output_port)) |
| output_port += 1 |
| |
| ################################################## |
| # Asynch Message Connections |
| ################################################## |
| self.msg_connect(self, "ppm_in", self.gsm_clock_offset_corrector_0, "ppm_in") |
| |
| def get_ppm(self): |
| return self.ppm |
| |
| def set_ppm(self, ppm): |
| self.ppm = ppm |
| self.gsm_clock_offset_corrector_0.set_ppm(self.ppm) |
| |
| def get_fc(self): |
| return self.fc |
| |
| def set_fc(self, fc): |
| self.fc = fc |
| self.gsm_clock_offset_corrector_0.set_fc(self.fc) |
| |
| def get_osr(self): |
| return self.osr |
| |
| def set_osr(self, osr): |
| self.osr = osr |
| self.set_samp_rate_out(1625000.0/6.0*self.osr) |
| |
| def get_samp_rate_in(self): |
| return self.samp_rate_in |
| |
| def set_samp_rate_in(self, samp_rate_in): |
| self.samp_rate_in = samp_rate_in |
| for channel in self.blocks_resamplers: |
| self.blocks_resamplers[channel].set_resamp_ratio(self.samp_rate_in / self.samp_rate_out) |
| self.gsm_clock_offset_corrector_0.set_samp_rate_in(self.samp_rate_in) |
| |
| def get_samp_rate_out(self): |
| return self.samp_rate_out |
| |
| def set_samp_rate_out(self, samp_rate_out): |
| self.samp_rate_out = samp_rate_out |
| for channel in self.blocks_resamplers: |
| self.blocks_resamplers[channel].set_resamp_ratio(self.samp_rate_in / self.samp_rate_out) |