git.gag.com Git - debian/gnuradio/blob - gnuradio-examples/python/gmsk2/qpsk_tester.py

   1 #!/usr/bin/env python
   2
   3 import random
   4 from gnuradio import gr
   5
   6 default_access_code = '\xAC\xDD\xA4\xE2\xF2\x8C\x20\xFC'
   7
   8 def string_to_1_0_list(s):
   9     r = []
  10     for ch in s:
  11         x = ord(ch)
  12         for i in range(8):
  13             t = (x >> i) & 0x1
  14             r.append(t)
  15
  16     return r
  17
  18 def to_1_0_string(L):
  19     return ''.join(map(lambda x: chr(x + ord('0')), L))
  20
  21 code = string_to_1_0_list(default_access_code)
  22 access_code = to_1_0_string(code)
  23
  24 use_agc        = 0
  25 use_rrc_tx     = 1
  26 use_rrc_rx     = 1
  27 use_sync_loop  = 1
  28 use_clock_sync = 1
  29
  30 def main():
  31     fg = gr.flow_graph()
  32
  33 #    data = (1,2,3,4,5,6,7,8,9)
  34     random.seed()
  35     data = [random.randint(1,100) for i in range(20000)]
  36     data[0] = 0 # you know, for the diff encoding stuff
  37     bytes_src = gr.vector_source_b(data,False)
  38
  39     k = 2
  40     spb = 50
  41     ntaps = 11*spb
  42     excess_bw = 0.9
  43     threshold = 12
  44     constellation  = (1+0j, 0+1j, -1+0j, 0-1j)
  45
  46     bytes2chunks   = gr.packed_to_unpacked_bb(k, gr.GR_MSB_FIRST)
  47     diffenc        = gr.diff_encoder_bb(4)
  48     chunks2symbols = gr.chunks_to_symbols_bc(constellation)
  49
  50     if use_rrc_tx:
  51         rrc_taps_tx = gr.firdes.root_raised_cosine(spb, spb, 1.0, \
  52                                                    excess_bw, ntaps)
  53         rrc_tx = gr.interp_fir_filter_ccf(spb, rrc_taps_tx)
  54     else:
  55         rrc_tx = gr.interp_fir_filter_ccf(1, (1,))
  56
  57 ################### CHANNEL MODEL #############################
  58
  59     phase_rotate = gr.multiply_const_cc(1-0.36j)
  60     channel      = gr.add_cc()
  61     awgn         = gr.noise_source_c(gr.GR_GAUSSIAN, 0.5)
  62     fg.connect(awgn, (channel,1))
  63
  64 ################### CHANNEL MODEL #############################
  65
  66     if use_agc:
  67         agc = gr.agc_cc(1e-4, 1, 1)
  68     else:
  69         agc = gr.multiply_const_cc(1)
  70
  71     # Downconverter
  72     if use_sync_loop:
  73         costas_alpha=0.005
  74         beta = costas_alpha*costas_alpha*0.25
  75         sync_loop = gr.costas_loop_cc(costas_alpha, beta, 0.05, -0.05, 0)
  76     else:
  77         sync_loop = gr.multiply_const_cc(1)
  78
  79     if use_rrc_rx:
  80         rrc_taps_rx = gr.firdes.root_raised_cosine(1, spb, 1.0, \
  81                                                    excess_bw, ntaps)
  82         rrc_rx = gr.fir_filter_ccf(1, rrc_taps_rx)
  83     else:
  84         rrc_rx = gr.fir_filter_ccf(1, (1,))
  85
  86     # Sampler
  87     if use_clock_sync:
  88         mu = 0.05
  89         omega = spb
  90         gain_mu = 0.05
  91         gain_omega = 0.25*gain_mu*gain_mu
  92         omega_rel_limit = 0.5
  93         clock_sync = gr.clock_recovery_mm_cc(omega, gain_omega, mu, \
  94                                              gain_mu, omega_rel_limit)
  95         #clock_sync.set_verbose(True);
  96     else:
  97         clock_sync = gr.fir_filter_ccf(1, (1,))
  98
  99     diff_phasor = gr.diff_phasor_cc()
 100     slicer = gr.constellation_decoder_cb((constellation), (0,1,2,3))
 101     unpack = gr.unpack_k_bits_bb(k)
 102     access = gr.correlate_access_code_bb(access_code,threshold)
 103
 104     sink = gr.file_sink(gr.sizeof_char, 'output.dat')
 105
 106     fg.connect(bytes_src, bytes2chunks, diffenc, chunks2symbols, rrc_tx)
 107     fg.connect(rrc_tx, phase_rotate, channel, agc)
 108     fg.connect(agc, sync_loop, rrc_rx, clock_sync, diff_phasor, slicer, sink)
 109
 110     test = gr.file_sink(gr.sizeof_gr_complex, 'test.dat')
 111     fg.connect(rrc_rx, test)
 112
 113     fg.connect(chunks2symbols, gr.file_sink(gr.sizeof_gr_complex, 'rrc_tx.dat'))  # into TX RRC
 114     fg.connect(channel, gr.file_sink(gr.sizeof_gr_complex, 'channel.dat'))        # Out of TX RRC
 115     fg.connect(rrc_rx, gr.file_sink(gr.sizeof_gr_complex, 'rrc_rx.dat'))          # Out of RX RRC -> clock_sync
 116     fg.connect(clock_sync, gr.file_sink(gr.sizeof_gr_complex, 'clock_sync.dat'))  # Out of M&M sync loop
 117     fg.connect(bytes2chunks, gr.file_sink(gr.sizeof_char, 'source.dat'))
 118
 119     fg.start()
 120     fg.wait()
 121
 122 if __name__ == "__main__":
 123     main()
 124
 125
 126
 127