3 # Copyright 2007 Free Software Foundation, Inc.
5 # This file is part of GNU Radio
7 # GNU Radio is free software; you can redistribute it and/or modify
8 # it under the terms of the GNU General Public License as published by
9 # the Free Software Foundation; either version 3, or (at your option)
12 # GNU Radio is distributed in the hope that it will be useful,
13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 # GNU General Public License for more details.
17 # You should have received a copy of the GNU General Public License
18 # along with GNU Radio; see the file COPYING. If not, write to
19 # the Free Software Foundation, Inc., 51 Franklin Street,
20 # Boston, MA 02110-1301, USA.
25 from gnuradio import gr
27 class ofdm_sync_pnac(gr.hier_block):
28 def __init__(self, fg, fft_length, cp_length, ks):
31 # FIXME: when converting to hier_block2's, the output signature
32 # should be the output of the divider (the normalized peaks) and
33 # the angle value out of the sample and hold block
35 self.input = gr.add_const_cc(0)
37 symbol_length = fft_length + cp_length
41 # autocorrelate with the known symbol
42 ks = ks[0:fft_length//2]
44 self.crosscorr_filter = gr.fir_filter_ccc(1, ks)
45 self.fg.connect(self.crosscorr_filter, gr.file_sink(gr.sizeof_gr_complex, "crosscorr.dat"))
48 self.delay = gr.delay(gr.sizeof_gr_complex, fft_length/2)
50 # Correlation from ML Sync
51 self.conjg = gr.conjugate_cc();
52 self.corr = gr.multiply_cc();
54 # Create a moving sum filter for the corr output
55 moving_sum_taps = [1.0 for i in range(fft_length//2)]
56 self.moving_sum_filter = gr.fir_filter_ccf(1,moving_sum_taps)
58 # Create a moving sum filter for the input
59 self.inputmag2 = gr.complex_to_mag_squared()
60 movingsum2_taps = [1.0 for i in range(fft_length/2)]
61 self.inputmovingsum = gr.fir_filter_fff(1,movingsum2_taps)
62 self.square = gr.multiply_ff()
63 self.normalize = gr.divide_ff()
65 # Get magnitude (peaks) and angle (phase/freq error)
66 self.c2mag = gr.complex_to_mag_squared()
67 self.angle = gr.complex_to_arg()
69 self.sample_and_hold = gr.sample_and_hold_ff()
71 # Mix the signal with an NCO controlled by the sync loop
72 nco_sensitivity = -1.0/fft_length
73 self.nco = gr.frequency_modulator_fc(nco_sensitivity)
74 self.sigmix = gr.multiply_cc()
76 #ML measurements input to sampler block and detect
77 self.sub1 = gr.add_const_ff(-1)
78 self.pk_detect = gr.peak_detector_fb(0.2, 0.25, 30, 0.0005)
80 self.sampler = gr.ofdm_sampler(fft_length,symbol_length)
82 self.fg.connect(self.input, self.crosscorr_filter)
83 self.fg.connect(self.crosscorr_filter, self.delay)
84 self.fg.connect(self.crosscorr_filter, (self.corr,0))
85 self.fg.connect(self.delay, self.conjg)
86 self.fg.connect(self.conjg, (self.corr,1))
87 self.fg.connect(self.corr, self.moving_sum_filter)
88 self.fg.connect(self.moving_sum_filter, self.c2mag)
89 self.fg.connect(self.moving_sum_filter, self.angle)
90 self.fg.connect(self.angle, (self.sample_and_hold,0))
91 self.fg.connect(self.sample_and_hold, self.nco)
93 self.fg.connect(self.input, (self.sigmix,0))
94 self.fg.connect(self.nco, (self.sigmix,1))
95 self.fg.connect(self.sigmix, (self.sampler,0))
97 self.fg.connect(self.input, self.inputmag2, self.inputmovingsum)
98 self.fg.connect(self.inputmovingsum, (self.square,0))
99 self.fg.connect(self.inputmovingsum, (self.square,1))
100 self.fg.connect(self.square, (self.normalize,1))
101 self.fg.connect(self.c2mag, (self.normalize,0))
102 self.fg.connect(self.normalize, self.sub1, self.pk_detect)
104 self.fg.connect(self.pk_detect, (self.sampler,1))
105 self.fg.connect(self.pk_detect, (self.sample_and_hold,1))
109 self.fg.connect(self.normalize, gr.file_sink(gr.sizeof_float,
110 "ofdm_sync_pnac-theta_f.dat"))
111 self.fg.connect(self.angle, gr.file_sink(gr.sizeof_float,
112 "ofdm_sync_pnac-epsilon_f.dat"))
113 self.fg.connect(self.pk_detect, gr.file_sink(gr.sizeof_char,
114 "ofdm_sync_pnac-peaks_b.dat"))
115 self.fg.connect(self.sigmix, gr.file_sink(gr.sizeof_gr_complex,
116 "ofdm_sync_pnac-sigmix_c.dat"))
117 self.fg.connect(self.sampler, gr.file_sink(gr.sizeof_gr_complex*fft_length,
118 "ofdm_sync_pnac-sampler_c.dat"))
119 self.fg.connect(self.sample_and_hold, gr.file_sink(gr.sizeof_float,
120 "ofdm_sync_pnac-sample_and_hold_f.dat"))
121 self.fg.connect(self.nco, gr.file_sink(gr.sizeof_gr_complex,
122 "ofdm_sync_pnac-nco_c.dat"))
123 self.fg.connect(self.input, gr.file_sink(gr.sizeof_gr_complex,
124 "ofdm_sync_pnac-input_c.dat"))
126 gr.hier_block.__init__(self, fg, self.input, self.sampler)