4 from gnuradio import gr, gru, usrp
6 default_access_code = '\xAC\xDD\xA4\xE2\xF2\x8C\x20\xFC'
8 def string_to_1_0_list(s):
19 return ''.join(map(lambda x: chr(x + ord('0')), L))
21 code = string_to_1_0_list(default_access_code)
23 access_code = to_1_0_string(code)
36 src = usrp.source_c ()
37 adc_rate = src.adc_rate()
38 usrp_decim = int(adc_rate / fs)
39 src.set_decim_rate(usrp_decim)
41 subdev_spec = usrp.pick_rx_subdevice(src)
42 subdev = usrp.selected_subdev(src, subdev_spec)
43 print "Using RX d'board %s" % (subdev.side_and_name(),)
44 src.set_mux(usrp.determine_rx_mux_value(src, subdev_spec))
45 src.tune(0, subdev, f_rf)
47 g = subdev.gain_range()
49 subdev.set_auto_tr(True)
51 print "USRP Decimation Rate = %d" % usrp_decim
52 print "RF Frequency = %d" % f_rf
54 agc = gr.multiply_const_cc(0.0025)
58 beta = costas_alpha*costas_alpha*0.25
59 sync_loop = gr.costas_loop_cc(costas_alpha, beta, 0.05, -0.05, 0)
64 # decimator = gr.keep_one_in_n(gr.sizeof_gr_complex, D)
65 # print "D = %d\nAfter decimator fs = %f" % (D, fs2)
68 taps = gr.firdes.root_raised_cosine(1, fs, sr, alpha, 45)
69 rrc = gr.fir_filter_ccf(1, taps)
75 gain_omega = 0.25*gain_mu*gain_mu
77 clock_sync = gr.clock_recovery_mm_cc(omega, gain_omega, mu,
78 gain_mu, omega_rel_limit)
79 clock_sync.set_verbose(False)
81 diff_phasor = gr.diff_phasor_cc()
84 constellation = (1+0j, 0+1j, -1+0j, 0-1j)
85 slicer = gr.constellation_decoder_cb((constellation), (0,1,2,3))
86 unpack = gr.unpack_k_bits_bb(k)
87 access = gr.correlate_access_code_bb(access_code,threshold)
89 test = gr.file_sink(gr.sizeof_gr_complex, 'test.dat')
90 sink = gr.file_sink(gr.sizeof_char, 'output.dat')
92 fg.connect(src, agc, sync_loop, rrc, clock_sync)
93 fg.connect(clock_sync, diff_phasor, slicer, unpack, access, sink)
95 fg.connect(slicer, gr.file_sink(gr.sizeof_char, 'chunks.dat'))
96 fg.connect(unpack, gr.file_sink(gr.sizeof_char, 'unpack.dat'))
97 fg.connect(clock_sync, gr.file_sink(gr.sizeof_gr_complex, 'phasor.dat'))
102 if __name__ == "__main__":