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_block2):
28 def __init__(self, fft_length, cp_length, ks):
30 # FIXME: change the output signature
31 # should be the output of the divider (the normalized peaks) and
32 # the angle value out of the sample and hold block
33 # move sampler out of this block
35 gr.hier_block2.__init__(self, "ofdm_sync_pnac",
36 gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
37 gr.io_signature(1, 1, gr.sizeof_gr_complex*fft_length)) # Output signature
40 self.input = gr.add_const_cc(0)
42 symbol_length = fft_length + cp_length
46 # autocorrelate with the known symbol
47 ks = ks[0:fft_length//2]
49 self.crosscorr_filter = gr.fir_filter_ccc(1, ks)
50 self.connect(self.crosscorr_filter, gr.file_sink(gr.sizeof_gr_complex, "crosscorr.dat"))
53 self.delay = gr.delay(gr.sizeof_gr_complex, fft_length/2)
55 # Correlation from ML Sync
56 self.conjg = gr.conjugate_cc();
57 self.corr = gr.multiply_cc();
59 # Create a moving sum filter for the corr output
60 moving_sum_taps = [1.0 for i in range(fft_length//2)]
61 self.moving_sum_filter = gr.fir_filter_ccf(1,moving_sum_taps)
63 # Create a moving sum filter for the input
64 self.inputmag2 = gr.complex_to_mag_squared()
65 movingsum2_taps = [1.0 for i in range(fft_length/2)]
66 self.inputmovingsum = gr.fir_filter_fff(1,movingsum2_taps)
67 self.square = gr.multiply_ff()
68 self.normalize = gr.divide_ff()
70 # Get magnitude (peaks) and angle (phase/freq error)
71 self.c2mag = gr.complex_to_mag_squared()
72 self.angle = gr.complex_to_arg()
74 self.sample_and_hold = gr.sample_and_hold_ff()
76 # Mix the signal with an NCO controlled by the sync loop
77 nco_sensitivity = -1.0/fft_length
78 self.nco = gr.frequency_modulator_fc(nco_sensitivity)
79 self.sigmix = gr.multiply_cc()
81 #ML measurements input to sampler block and detect
82 self.sub1 = gr.add_const_ff(-1)
83 self.pk_detect = gr.peak_detector_fb(0.2, 0.25, 30, 0.0005)
85 self.sampler = gr.ofdm_sampler(fft_length,symbol_length)
87 self.connect(self, self.input)
88 self.connect(self.input, self.crosscorr_filter)
89 self.connect(self.crosscorr_filter, self.delay)
90 self.connect(self.crosscorr_filter, (self.corr,0))
91 self.connect(self.delay, self.conjg)
92 self.connect(self.conjg, (self.corr,1))
93 self.connect(self.corr, self.moving_sum_filter)
94 self.connect(self.moving_sum_filter, self.c2mag)
95 self.connect(self.moving_sum_filter, self.angle)
96 self.connect(self.angle, (self.sample_and_hold,0))
97 self.connect(self.sample_and_hold, self.nco)
99 self.connect(self.input, (self.sigmix,0))
100 self.connect(self.nco, (self.sigmix,1))
101 self.connect(self.sigmix, (self.sampler,0))
103 self.connect(self.input, self.inputmag2, self.inputmovingsum)
104 self.connect(self.inputmovingsum, (self.square,0))
105 self.connect(self.inputmovingsum, (self.square,1))
106 self.connect(self.square, (self.normalize,1))
107 self.connect(self.c2mag, (self.normalize,0))
108 self.connect(self.normalize, self.sub1, self.pk_detect)
110 self.connect(self.pk_detect, (self.sampler,1))
111 self.connect(self.pk_detect, (self.sample_and_hold,1))
113 self.connect(self.sampler, self)
116 self.connect(self.normalize, gr.file_sink(gr.sizeof_float,
117 "ofdm_sync_pnac-theta_f.dat"))
118 self.connect(self.angle, gr.file_sink(gr.sizeof_float,
119 "ofdm_sync_pnac-epsilon_f.dat"))
120 self.connect(self.pk_detect, gr.file_sink(gr.sizeof_char,
121 "ofdm_sync_pnac-peaks_b.dat"))
122 self.connect(self.sigmix, gr.file_sink(gr.sizeof_gr_complex,
123 "ofdm_sync_pnac-sigmix_c.dat"))
124 self.connect(self.sampler, gr.file_sink(gr.sizeof_gr_complex*fft_length,
125 "ofdm_sync_pnac-sampler_c.dat"))
126 self.connect(self.sample_and_hold, gr.file_sink(gr.sizeof_float,
127 "ofdm_sync_pnac-sample_and_hold_f.dat"))
128 self.connect(self.nco, gr.file_sink(gr.sizeof_gr_complex,
129 "ofdm_sync_pnac-nco_c.dat"))
130 self.connect(self.input, gr.file_sink(gr.sizeof_gr_complex,
131 "ofdm_sync_pnac-input_c.dat"))