| #!/usr/bin/env python |
| |
| import gsm |
| from gnuradio.eng_option import eng_option |
| from gnuradio import gr, gru, blocks |
| from gnuradio import filter |
| |
| |
| class tuner(gr.feval_dd): |
| def __init__(self, top_block): |
| gr.feval_dd.__init__(self) |
| self.top_block = top_block |
| def eval(self, freq_offet): |
| self.top_block.set_center_frequency(freq_offet) |
| return freq_offet |
| |
| class receiver_hier(gr.hier_block2): |
| def __init__(self, input_rate, osr=4): |
| gr.hier_block2.__init__(self, |
| "receiver_hier", |
| gr.io_signature(1, 1, gr.sizeof_gr_complex), |
| gr.io_signature(1, 1, 142*gr.sizeof_float)) |
| #set rates |
| gsm_symb_rate = 1625000/6.0 |
| self.input_rate = input_rate |
| self.osr = osr |
| self.sps = input_rate / gsm_symb_rate / osr |
| |
| #create callbacks |
| self.tuner_callback = tuner(self) |
| #create accompaning blocks |
| self.filtr = self._set_filter() |
| self.interpolator = self._set_interpolator() |
| self.receiver = self._set_receiver() |
| self.connect(self, self.filtr, self.interpolator, self.receiver, self) |
| |
| def _set_filter(self): |
| filter_cutoff = 125e3 |
| filter_t_width = 10e3 |
| offset = 0 |
| |
| filter_taps = filter.firdes.low_pass(1.0, self.input_rate, filter_cutoff, filter_t_width, filter.firdes.WIN_HAMMING) |
| filtr = filter.freq_xlating_fir_filter_ccf(1, filter_taps, offset, self.input_rate) |
| return filtr |
| |
| def _set_interpolator(self): |
| interpolator = filter.fractional_resampler_cc(0, self.sps) |
| return interpolator |
| |
| def _set_receiver(self): |
| receiver = gsm.receiver(self.tuner_callback, self.osr) |
| return receiver |
| |
| def set_center_frequency(self, center_freq): |
| self.filtr.set_center_freq(center_freq) |
| |
| def set_timing(self, timing_offset): |
| pass |
| |