def __init__(self,
N,
sps,
rolloff,
ntaps,
bw,
noise,
foffset,
toffset,
poffset,
mode=0):
gr.top_block.__init__(self)
rrc_taps = gr.firdes.root_raised_cosine(sps, sps, 1.0, rolloff, ntaps)
gain = 2 * scipy.pi / 100.0
nfilts = 32
rrc_taps_rx = gr.firdes.root_raised_cosine(nfilts, sps * nfilts, 1.0,
rolloff, ntaps * nfilts)
data = 2.0 * scipy.random.randint(0, 2, N) - 1.0
data = scipy.exp(1j * poffset) * data
self.src = gr.vector_source_c(data.tolist(), False)
self.rrc = gr.interp_fir_filter_ccf(sps, rrc_taps)
self.chn = gr.channel_model(noise, foffset, toffset)
self.off = gr.fractional_interpolator_cc(0.20, 1.0)
if mode == 0:
self.clk = gr.pfb_clock_sync_ccf(sps, gain, rrc_taps_rx, nfilts,
nfilts // 2, 3.5)
self.taps = self.clk.get_taps()
self.dtaps = self.clk.get_diff_taps()
self.vsnk_err = gr.vector_sink_f()
self.vsnk_rat = gr.vector_sink_f()
self.vsnk_phs = gr.vector_sink_f()
self.connect((self.clk, 1), self.vsnk_err)
self.connect((self.clk, 2), self.vsnk_rat)
self.connect((self.clk, 3), self.vsnk_phs)
else: # mode == 1
mu = 0.5
gain_mu = 0.1
gain_omega = 0.25 * gain_mu * gain_mu
omega_rel_lim = 0.02
self.clk = digital.clock_recovery_mm_cc(sps, gain_omega, mu,
gain_mu, omega_rel_lim)
self.vsnk_err = gr.vector_sink_f()
self.connect((self.clk, 1), self.vsnk_err)
self.vsnk_src = gr.vector_sink_c()
self.vsnk_clk = gr.vector_sink_c()
self.connect(self.src, self.rrc, self.chn, self.off, self.clk,
self.vsnk_clk)
self.connect(self.off, self.vsnk_src)
def __init__(self, N, sps, rolloff, ntaps, bw, noise,
foffset, toffset, poffset, mode=0):
gr.top_block.__init__(self)
rrc_taps = gr.firdes.root_raised_cosine(
sps, sps, 1.0, rolloff, ntaps)
gain = 2*scipy.pi/100.0
nfilts = 32
rrc_taps_rx = gr.firdes.root_raised_cosine(
nfilts, sps*nfilts, 1.0, rolloff, ntaps*nfilts)
data = 2.0*scipy.random.randint(0, 2, N) - 1.0
data = scipy.exp(1j*poffset) * data
self.src = gr.vector_source_c(data.tolist(), False)
self.rrc = gr.interp_fir_filter_ccf(sps, rrc_taps)
self.chn = gr.channel_model(noise, foffset, toffset)
self.off = gr.fractional_interpolator_cc(0.20, 1.0)
if mode == 0:
self.clk = gr.pfb_clock_sync_ccf(sps, gain, rrc_taps_rx,
nfilts, nfilts//2, 3.5)
self.taps = self.clk.get_taps()
self.dtaps = self.clk.get_diff_taps()
self.vsnk_err = gr.vector_sink_f()
self.vsnk_rat = gr.vector_sink_f()
self.vsnk_phs = gr.vector_sink_f()
self.connect((self.clk,1), self.vsnk_err)
self.connect((self.clk,2), self.vsnk_rat)
self.connect((self.clk,3), self.vsnk_phs)
else: # mode == 1
mu = 0.5
gain_mu = 0.1
gain_omega = 0.25*gain_mu*gain_mu
omega_rel_lim = 0.02
self.clk = digital.clock_recovery_mm_cc(sps, gain_omega,
mu, gain_mu,
omega_rel_lim)
self.vsnk_err = gr.vector_sink_f()
self.connect((self.clk,1), self.vsnk_err)
self.vsnk_src = gr.vector_sink_c()
self.vsnk_clk = gr.vector_sink_c()
self.connect(self.src, self.rrc, self.chn, self.off, self.clk, self.vsnk_clk)
self.connect(self.off, self.vsnk_src)
def __init__(self, sample_rate, symbol_rate):
gr.hier_block2.__init__(
self,
"dvb_s_demodulator2_cc",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
samples_per_symbol = sample_rate / symbol_rate
# Automatic gain control
self.agc = gr.agc2_cc(
0.06, # Attack rate
0.001, # Decay rate
1, # Reference
1, # Initial gain
100) # Max gain
# Frequency correction with band-edge filters FLL
freq_beta = freq_alpha * freq_alpha / 4
self.freq_recov = digital.fll_band_edge_cc(
samples_per_symbol,
dvb_swig.RRC_ROLLOFF_FACTOR,
11 * int(samples_per_symbol), # Size of the filter in taps
freq_bw)
self.freq_recov.set_alpha(freq_alpha)
self.freq_recov.set_beta(freq_beta)
# Symbol timing recovery with RRC data filter
ntaps = 11 * int(samples_per_symbol * nfilts)
rrc_taps = gr.firdes.root_raised_cosine(nfilts, nfilts,
1.0 / samples_per_symbol,
dvb_swig.RRC_ROLLOFF_FACTOR,
ntaps)
self.time_recov = gr.pfb_clock_sync_ccf(
samples_per_symbol, # Samples per second in the incoming signal
timing_alpha, # Alpha gain of control loop
rrc_taps, # The filter taps
nfilts, # Number of filters in the filter bank
nfilts /
2) # Initial phase to look at (or which filter to start with)
self.time_recov.set_beta(timing_beta)
# Perform phase / fine frequency correction using Costas PLL
phase_beta = phase_alpha * phase_alpha / 4
self.phase_recov = digital.costas_loop_cc(phase_bw, M)
self.phase_recov.set_alpha(phase_alpha)
self.phase_recov.set_beta(phase_beta)
self.connect(self, self.agc, self.freq_recov, self.time_recov,
self.phase_recov, self)
def __init__(self, sample_rate, symbol_rate): gr.hier_block2.__init__(self, "dvb_s_demodulator2_cc", gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature samples_per_symbol = sample_rate / symbol_rate # Automatic gain control self.agc = gr.agc2_cc( 0.06, # Attack rate 0.001, # Decay rate 1, # Reference 1, # Initial gain 100) # Max gain # Frequency correction with band-edge filters FLL freq_beta = freq_alpha * freq_alpha / 4 self.freq_recov = digital.fll_band_edge_cc( samples_per_symbol, dvb_swig.RRC_ROLLOFF_FACTOR, 11 * int(samples_per_symbol), # Size of the filter in taps freq_bw) self.freq_recov.set_alpha(freq_alpha) self.freq_recov.set_beta(freq_beta) # Symbol timing recovery with RRC data filter ntaps = 11 * int(samples_per_symbol * nfilts) rrc_taps = gr.firdes.root_raised_cosine(nfilts, nfilts, 1.0 / samples_per_symbol, dvb_swig.RRC_ROLLOFF_FACTOR, ntaps) self.time_recov = gr.pfb_clock_sync_ccf( samples_per_symbol, # Samples per second in the incoming signal timing_alpha, # Alpha gain of control loop rrc_taps, # The filter taps nfilts, # Number of filters in the filter bank nfilts / 2) # Initial phase to look at (or which filter to start with) self.time_recov.set_beta(timing_beta) # Perform phase / fine frequency correction using Costas PLL phase_beta = phase_alpha * phase_alpha / 4 self.phase_recov = digital.costas_loop_cc(phase_bw, M) self.phase_recov.set_alpha(phase_alpha) self.phase_recov.set_beta(phase_beta) self.connect(self, self.agc, self.freq_recov, self.time_recov, self.phase_recov, self)
def __init__(self, constellation,
samples_per_symbol=_def_samples_per_symbol,
differential=_def_differential,
excess_bw=_def_excess_bw,
gray_coded=True,
freq_bw=_def_freq_bw,
timing_bw=_def_timing_bw,
phase_bw=_def_phase_bw,
verbose=_def_verbose,
log=_def_log):
"""
Hierarchical block for RRC-filtered differential generic demodulation.
The input is the complex modulated signal at baseband.
The output is a stream of bits packed 1 bit per byte (LSB)
@param constellation: determines the modulation type
@type constellation: gnuradio.digital.gr_constellation
@param samples_per_symbol: samples per symbol >= 2
@type samples_per_symbol: float
@param excess_bw: Root-raised cosine filter excess bandwidth
@type excess_bw: float
@param gray_coded: turn gray coding on/off
@type gray_coded: bool
@param freq_bw: loop filter lock-in bandwidth
@type freq_bw: float
@param timing_bw: timing recovery loop lock-in bandwidth
@type timing_bw: float
@param phase_bw: phase recovery loop bandwidth
@type phase_bw: float
@param verbose: Print information about modulator?
@type verbose: bool
@param debug: Print modualtion data to files?
@type debug: bool
"""
gr.hier_block2.__init__(self, "generic_demod",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
self._constellation = constellation.base()
self._samples_per_symbol = samples_per_symbol
self._excess_bw = excess_bw
self._phase_bw = phase_bw
self._freq_bw = freq_bw
self._timing_bw = timing_bw
self._timing_max_dev= _def_timing_max_dev
self._differential = differential
if self._samples_per_symbol < 2:
raise TypeError, ("sbp must be >= 2, is %d" % self._samples_per_symbol)
arity = pow(2,self.bits_per_symbol())
nfilts = 32
ntaps = 11 * int(self._samples_per_symbol*nfilts)
# Automatic gain control
self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
# Frequency correction
fll_ntaps = 55
self.freq_recov = digital_swig.fll_band_edge_cc(self._samples_per_symbol, self._excess_bw,
fll_ntaps, self._freq_bw)
# symbol timing recovery with RRC data filter
taps = gr.firdes.root_raised_cosine(nfilts, nfilts*self._samples_per_symbol,
1.0, self._excess_bw, ntaps)
self.time_recov = gr.pfb_clock_sync_ccf(self._samples_per_symbol,
self._timing_bw, taps,
nfilts, nfilts//2, self._timing_max_dev)
fmin = -0.25
fmax = 0.25
self.receiver = digital_swig.constellation_receiver_cb(
self._constellation, self._phase_bw,
fmin, fmax)
# Do differential decoding based on phase change of symbols
if differential:
self.diffdec = gr.diff_decoder_bb(arity)
if gray_coded:
self.symbol_mapper = gr.map_bb(
mod_codes.invert_code(self._constellation.pre_diff_code()))
# unpack the k bit vector into a stream of bits
self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
if verbose:
self._print_verbage()
if log:
self._setup_logging()
# Connect and Initialize base class
blocks = [self, self.agc, self.freq_recov,
self.time_recov, self.receiver]
if differential:
blocks.append(self.diffdec)
if self._constellation.apply_pre_diff_code():
blocks.append(self.symbol_mapper)
blocks += [self.unpack, self]
self.connect(*blocks)
def __init__(self, options):
gr.hier_block2.__init__(
self,
"ais_demod",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
gr.io_signature(1, 1, gr.sizeof_char),
) # Output signature
self._samples_per_symbol = options.samples_per_symbol
self._bits_per_sec = options.bits_per_sec
self._samplerate = self._samples_per_symbol * self._bits_per_sec
self._gain_mu = options.gain_mu
self._mu = options.mu
self._omega_relative_limit = options.omega_relative_limit
self.fftlen = options.fftlen
# right now we are going to hardcode the different options for VA mode here. later on we can use configurable options
samples_per_symbol_viterbi = 2
bits_per_symbol = 2
samples_per_symbol = 6
samples_per_symbol_clockrec = samples_per_symbol / bits_per_symbol
BT = 0.4
data_rate = 9600.0
samp_rate = options.samp_rate
self.gmsk_sync = gmsk_sync.square_and_fft_sync(self._samplerate, self._bits_per_sec, self.fftlen)
if options.viterbi is True:
# calculate the required decimation and interpolation to achieve the desired samples per symbol
denom = gcd(data_rate * samples_per_symbol, samp_rate)
cr_interp = int(data_rate * samples_per_symbol / denom)
cr_decim = int(samp_rate / denom)
self.resample = blks2.rational_resampler_ccc(cr_interp, cr_decim)
# here we take a different tack and use A.A.'s CPM decomposition technique
self.clockrec = gr.clock_recovery_mm_cc(
samples_per_symbol_clockrec, 0.005 * 0.005 * 0.25, 0.5, 0.005, 0.0005
) # might have to futz with the max. deviation
(fsm, constellation, MF, N, f0T) = make_gmsk(
samples_per_symbol_viterbi, BT
) # calculate the decomposition required for demodulation
self.costas = gr.costas_loop_cc(
0.015, 0.015 * 0.015 * 0.25, 100e-6, -100e-6, 4
) # does fine freq/phase synchronization. should probably calc the coeffs instead of hardcode them.
self.streams2stream = gr.streams_to_stream(int(gr.sizeof_gr_complex * 1), int(N))
self.mf0 = gr.fir_filter_ccc(
samples_per_symbol_viterbi, MF[0].conjugate()
) # two matched filters for decomposition
self.mf1 = gr.fir_filter_ccc(samples_per_symbol_viterbi, MF[1].conjugate())
self.fo = gr.sig_source_c(
samples_per_symbol_viterbi, gr.GR_COS_WAVE, -f0T, 1, 0
) # the memoryless modulation component of the decomposition
self.fomult = gr.multiply_cc(1)
self.trellis = trellis.viterbi_combined_cb(
fsm, int(data_rate), -1, -1, int(N), constellation, trellis.TRELLIS_EUCLIDEAN
) # the actual Viterbi decoder
else:
# this is probably not optimal and someone who knows what they're doing should correct me
self.datafiltertaps = gr.firdes.root_raised_cosine(
10, # gain
self._samplerate * 32, # sample rate
self._bits_per_sec, # symbol rate
0.4, # alpha, same as BT?
50 * 32,
) # no. of taps
self.datafilter = gr.fir_filter_fff(1, self.datafiltertaps)
sensitivity = (math.pi / 2) / self._samples_per_symbol
self.demod = gr.quadrature_demod_cf(sensitivity) # param is gain
# self.clockrec = digital.clock_recovery_mm_ff(self._samples_per_symbol,0.25*self._gain_mu*self._gain_mu,self._mu,self._gain_mu,self._omega_relative_limit)
self.clockrec = gr.pfb_clock_sync_ccf(self._samples_per_symbol, 0.04, self.datafiltertaps, 32, 0, 1.15)
self.tcslicer = digital.digital.binary_slicer_fb()
# self.dfe = digital.digital.lms_dd_equalizer_cc(
# 32,
# 0.005,
# 1,
# digital.digital.constellation_bpsk()
# )
# self.delay = gr.delay(gr.sizeof_float, 64 + 16) #the correlator delays 64 bits, and the LMS delays some as well.
self.slicer = digital.digital.binary_slicer_fb()
# self.training_correlator = digital.correlate_access_code_bb("1100110011001100", 0)
# self.cma = digital.cma_equalizer_cc
# just a note here: a complex combined quad demod/slicer could be based on if's rather than an actual quad demod, right?
# in fact all the constellation decoders up to QPSK could operate on complex data w/o doing the whole atan thing
self.diff = gr.diff_decoder_bb(2)
self.invert = ais.invert() # NRZI signal diff decoded and inverted should give original signal
self.connect(self, self.gmsk_sync)
if options.viterbi is False:
self.connect(self.gmsk_sync, self.clockrec, self.demod, self.slicer, self.diff, self.invert, self)
# self.connect(self.gmsk_sync, self.demod, self.clockrec, self.tcslicer, self.training_correlator)
# self.connect(self.clockrec, self.delay, (self.dfe, 0))
# self.connect(self.training_correlator, (self.dfe, 1))
# self.connect(self.dfe, self.slicer, self.diff, self.invert, self)
else:
self.connect(self.gmsk_sync, self.costas, self.resample, self.clockrec)
self.connect(self.clockrec, (self.fomult, 0))
self.connect(self.fo, (self.fomult, 1))
self.connect(self.fomult, self.mf0)
self.connect(self.fomult, self.mf1)
self.connect(self.mf0, (self.streams2stream, 0))
self.connect(self.mf1, (self.streams2stream, 1))
self.connect(self.streams2stream, self.trellis, self.diff, self.invert, self)
def __init__(self,
samples_per_symbol=_def_samples_per_symbol,
excess_bw=_def_excess_bw,
costas_alpha=_def_costas_alpha,
timing_alpha=_def_timing_alpha,
timing_max_dev=_def_timing_max_dev,
gray_code=_def_gray_code,
verbose=_def_verbose,
log=_def_log):
"""
Hierarchical block for RRC-filtered DQPSK demodulation
The input is the complex modulated signal at baseband.
The output is a stream of bits packed 1 bit per byte (LSB)
@param samples_per_symbol: samples per symbol >= 2
@type samples_per_symbol: float
@param excess_bw: Root-raised cosine filter excess bandwidth
@type excess_bw: float
@param costas_alpha: loop filter gain
@type costas_alphas: float
@param timing_alpha: timing loop alpha gain
@type timing_alpha: float
@param timing_max: timing loop maximum rate deviations
@type timing_max: float
@param gray_code: Tell modulator to Gray code the bits
@type gray_code: bool
@param verbose: Print information about modulator?
@type verbose: bool
@param debug: Print modualtion data to files?
@type debug: bool
"""
gr.hier_block2.__init__(self, "dqpsk2_demod",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
self._samples_per_symbol = samples_per_symbol
self._excess_bw = excess_bw
self._costas_alpha = costas_alpha
self._timing_alpha = timing_alpha
self._timing_beta = _def_timing_beta
self._timing_max_dev=timing_max_dev
self._gray_code = gray_code
if samples_per_symbol < 2:
raise TypeError, "sbp must be >= 2, is %d" % samples_per_symbol
arity = pow(2,self.bits_per_symbol())
# Automatic gain control
self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
#self.agc = gr.feedforward_agc_cc(16, 2.0)
self._costas_beta = 0.25 * self._costas_alpha * self._costas_alpha
# Allow a frequency swing of +/- half of the sample rate
fmin = -0.5
fmax = 0.5
self.clock_recov = gr.costas_loop_cc(self._costas_alpha,
self._costas_beta,
fmax, fmin, arity)
# symbol timing recovery with RRC data filter
nfilts = 32
ntaps = 11 * samples_per_symbol*nfilts
taps = gr.firdes.root_raised_cosine(nfilts, nfilts, 1.0/float(self._samples_per_symbol), self._excess_bw, ntaps)
self.time_recov = gr.pfb_clock_sync_ccf(self._samples_per_symbol,
self._timing_alpha,
taps, nfilts, nfilts/2, self._timing_max_dev)
self.time_recov.set_beta(self._timing_beta)
# Perform Differential decoding on the constellation
self.diffdec = gr.diff_phasor_cc()
# find closest constellation point
rot = 1
rotated_const = map(lambda pt: pt * rot, psk.constellation[arity])
self.slicer = gr.constellation_decoder_cb(rotated_const, range(arity))
if self._gray_code:
self.symbol_mapper = gr.map_bb(psk.gray_to_binary[arity])
else:
self.symbol_mapper = gr.map_bb(psk.ungray_to_binary[arity])
# unpack the k bit vector into a stream of bits
self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
if verbose:
self._print_verbage()
if log:
self._setup_logging()
# Connect
self.connect(self, self.agc,
self.clock_recov,
self.time_recov,
self.diffdec, self.slicer, self.symbol_mapper, self.unpack, self)
def __init__(self,
samples_per_symbol=_def_samples_per_symbol,
excess_bw=_def_excess_bw,
freq_alpha=_def_freq_alpha,
phase_alpha=_def_phase_alpha,
timing_alpha=_def_timing_alpha,
timing_max_dev=_def_timing_max_dev,
gray_code=_def_gray_code,
verbose=_def_verbose,
log=_def_log,
sync_out=False):
"""
Hierarchical block for RRC-filtered DQPSK demodulation
The input is the complex modulated signal at baseband.
The output is a stream of bits packed 1 bit per byte (LSB)
@param samples_per_symbol: samples per symbol >= 2
@type samples_per_symbol: float
@param excess_bw: Root-raised cosine filter excess bandwidth
@type excess_bw: float
@param freq_alpha: loop filter gain for frequency recovery
@type freq_alpha: float
@param phase_alpha: loop filter gain
@type phase_alphas: float
@param timing_alpha: timing loop alpha gain
@type timing_alpha: float
@param timing_max: timing loop maximum rate deviations
@type timing_max: float
@param gray_code: Tell modulator to Gray code the bits
@type gray_code: bool
@param verbose: Print information about modulator?
@type verbose: bool
@param log: Print modualtion data to files?
@type log: bool
@param sync_out: Output a sync signal on :1?
@type sync_out: bool
"""
if sync_out:
io_sig_out = gr.io_signaturev(
2, 2, (gr.sizeof_char, gr.sizeof_gr_complex))
else:
io_sig_out = gr.io_signature(1, 1, gr.sizeof_char)
gr.hier_block2.__init__(
self,
"dqpsk2_demod",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
io_sig_out) # Output signature
self._samples_per_symbol = samples_per_symbol
self._excess_bw = excess_bw
self._freq_alpha = freq_alpha
self._freq_beta = 0.25 * self._freq_alpha**2
self._phase_alpha = phase_alpha
self._timing_alpha = timing_alpha
self._timing_beta = _def_timing_beta
self._timing_max_dev = timing_max_dev
self._gray_code = gray_code
if samples_per_symbol < 2:
raise TypeError, "sbp must be >= 2, is %d" % samples_per_symbol
arity = pow(2, self.bits_per_symbol())
# Automatic gain control
self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
#self.agc = gr.feedforward_agc_cc(16, 2.0)
# Frequency correction
self.freq_recov = gr.fll_band_edge_cc(
self._samples_per_symbol, self._excess_bw,
11 * int(self._samples_per_symbol), self._freq_alpha,
self._freq_beta)
# symbol timing recovery with RRC data filter
nfilts = 32
ntaps = 11 * int(samples_per_symbol * nfilts)
taps = gr.firdes.root_raised_cosine(
nfilts, nfilts, 1.0 / float(self._samples_per_symbol),
self._excess_bw, ntaps)
self.time_recov = gr.pfb_clock_sync_ccf(self._samples_per_symbol,
self._timing_alpha, taps,
nfilts, nfilts / 2,
self._timing_max_dev)
self.time_recov.set_beta(self._timing_beta)
# Perform phase / fine frequency correction
self._phase_beta = 0.25 * self._phase_alpha * self._phase_alpha
# Allow a frequency swing of +/- half of the sample rate
fmin = -0.5
fmax = 0.5
self.phase_recov = gr.costas_loop_cc(self._phase_alpha,
self._phase_beta, fmax, fmin,
arity)
# Perform Differential decoding on the constellation
self.diffdec = gr.diff_phasor_cc()
# find closest constellation point
rot = 1
rotated_const = map(lambda pt: pt * rot, psk.constellation[arity])
self.slicer = gr.constellation_decoder_cb(rotated_const, range(arity))
if self._gray_code:
self.symbol_mapper = gr.map_bb(psk.gray_to_binary[arity])
else:
self.symbol_mapper = gr.map_bb(psk.ungray_to_binary[arity])
# unpack the k bit vector into a stream of bits
self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
if verbose:
self._print_verbage()
if log:
self._setup_logging()
# Connect
self.connect(self, self.agc, self.freq_recov, self.time_recov,
self.phase_recov, self.diffdec, self.slicer,
self.symbol_mapper, self.unpack, self)
if sync_out: self.connect(self.time_recov, (self, 1))
def __init__(self, options):
gr.hier_block2.__init__(self, "ais_demod",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
self._samples_per_symbol = options.samples_per_symbol
self._bits_per_sec = options.bits_per_sec
self._samplerate = self._samples_per_symbol * self._bits_per_sec
self._gain_mu = options.gain_mu
self._mu = options.mu
self._omega_relative_limit = options.omega_relative_limit
self.fftlen = options.fftlen
#right now we are going to hardcode the different options for VA mode here. later on we can use configurable options
samples_per_symbol_viterbi = 2
bits_per_symbol = 2
samples_per_symbol = 6
samples_per_symbol_clockrec = samples_per_symbol / bits_per_symbol
BT = 0.4
data_rate = 9600.0
samp_rate = options.samp_rate
self.gmsk_sync = gmsk_sync.square_and_fft_sync(self._samplerate, self._bits_per_sec, self.fftlen)
if(options.viterbi is True):
#calculate the required decimation and interpolation to achieve the desired samples per symbol
denom = gcd(data_rate*samples_per_symbol, samp_rate)
cr_interp = int(data_rate*samples_per_symbol/denom)
cr_decim = int(samp_rate/denom)
self.resample = blks2.rational_resampler_ccc(cr_interp, cr_decim)
#here we take a different tack and use A.A.'s CPM decomposition technique
self.clockrec = gr.clock_recovery_mm_cc(samples_per_symbol_clockrec, 0.005*0.005*0.25, 0.5, 0.005, 0.0005) #might have to futz with the max. deviation
(fsm, constellation, MF, N, f0T) = make_gmsk(samples_per_symbol_viterbi, BT) #calculate the decomposition required for demodulation
self.costas = gr.costas_loop_cc(0.015, 0.015*0.015*0.25, 100e-6, -100e-6, 4) #does fine freq/phase synchronization. should probably calc the coeffs instead of hardcode them.
self.streams2stream = gr.streams_to_stream(int(gr.sizeof_gr_complex*1), int(N))
self.mf0 = gr.fir_filter_ccc(samples_per_symbol_viterbi, MF[0].conjugate()) #two matched filters for decomposition
self.mf1 = gr.fir_filter_ccc(samples_per_symbol_viterbi, MF[1].conjugate())
self.fo = gr.sig_source_c(samples_per_symbol_viterbi, gr.GR_COS_WAVE, -f0T, 1, 0) #the memoryless modulation component of the decomposition
self.fomult = gr.multiply_cc(1)
self.trellis = trellis.viterbi_combined_cb(fsm, int(data_rate), -1, -1, int(N), constellation, trellis.TRELLIS_EUCLIDEAN) #the actual Viterbi decoder
else:
#this is probably not optimal and someone who knows what they're doing should correct me
self.datafiltertaps = gr.firdes.root_raised_cosine(10, #gain
self._samplerate*32, #sample rate
self._bits_per_sec, #symbol rate
0.4, #alpha, same as BT?
50*32) #no. of taps
self.datafilter = gr.fir_filter_fff(1, self.datafiltertaps)
sensitivity = (math.pi / 2) / self._samples_per_symbol
self.demod = gr.quadrature_demod_cf(sensitivity) #param is gain
#self.clockrec = digital.clock_recovery_mm_ff(self._samples_per_symbol,0.25*self._gain_mu*self._gain_mu,self._mu,self._gain_mu,self._omega_relative_limit)
self.clockrec = gr.pfb_clock_sync_ccf(self._samples_per_symbol, 0.04, self.datafiltertaps, 32, 0, 1.15)
self.tcslicer = digital.digital.binary_slicer_fb()
# self.dfe = digital.digital.lms_dd_equalizer_cc(
# 32,
# 0.005,
# 1,
# digital.digital.constellation_bpsk()
# )
# self.delay = gr.delay(gr.sizeof_float, 64 + 16) #the correlator delays 64 bits, and the LMS delays some as well.
self.slicer = digital.digital.binary_slicer_fb()
# self.training_correlator = digital.correlate_access_code_bb("1100110011001100", 0)
# self.cma = digital.cma_equalizer_cc
#just a note here: a complex combined quad demod/slicer could be based on if's rather than an actual quad demod, right?
#in fact all the constellation decoders up to QPSK could operate on complex data w/o doing the whole atan thing
self.diff = gr.diff_decoder_bb(2)
self.invert = ais.invert() #NRZI signal diff decoded and inverted should give original signal
self.connect(self, self.gmsk_sync)
if(options.viterbi is False):
self.connect(self.gmsk_sync, self.clockrec, self.demod, self.slicer, self.diff, self.invert, self)
#self.connect(self.gmsk_sync, self.demod, self.clockrec, self.tcslicer, self.training_correlator)
#self.connect(self.clockrec, self.delay, (self.dfe, 0))
#self.connect(self.training_correlator, (self.dfe, 1))
#self.connect(self.dfe, self.slicer, self.diff, self.invert, self)
else:
self.connect(self.gmsk_sync, self.costas, self.resample, self.clockrec)
self.connect(self.clockrec, (self.fomult, 0))
self.connect(self.fo, (self.fomult, 1))
self.connect(self.fomult, self.mf0)
self.connect(self.fomult, self.mf1)
self.connect(self.mf0, (self.streams2stream, 0))
self.connect(self.mf1, (self.streams2stream, 1))
self.connect(self.streams2stream, self.trellis, self.diff, self.invert, self)
def __init__(self,
constellation,
samples_per_symbol=_def_samples_per_symbol,
differential=_def_differential,
excess_bw=_def_excess_bw,
gray_coded=True,
freq_bw=_def_freq_bw,
timing_bw=_def_timing_bw,
phase_bw=_def_phase_bw,
verbose=_def_verbose,
log=_def_log):
"""
Hierarchical block for RRC-filtered differential generic demodulation.
The input is the complex modulated signal at baseband.
The output is a stream of bits packed 1 bit per byte (LSB)
@param constellation: determines the modulation type
@type constellation: gnuradio.digital.gr_constellation
@param samples_per_symbol: samples per symbol >= 2
@type samples_per_symbol: float
@param excess_bw: Root-raised cosine filter excess bandwidth
@type excess_bw: float
@param gray_coded: turn gray coding on/off
@type gray_coded: bool
@param freq_bw: loop filter lock-in bandwidth
@type freq_bw: float
@param timing_bw: timing recovery loop lock-in bandwidth
@type timing_bw: float
@param phase_bw: phase recovery loop bandwidth
@type phase_bw: float
@param verbose: Print information about modulator?
@type verbose: bool
@param debug: Print modualtion data to files?
@type debug: bool
"""
gr.hier_block2.__init__(
self,
"generic_demod",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
gr.io_signature(1, 1, gr.sizeof_char)) # Output signature
self._constellation = constellation.base()
self._samples_per_symbol = samples_per_symbol
self._excess_bw = excess_bw
self._phase_bw = phase_bw
self._freq_bw = freq_bw
self._timing_bw = timing_bw
self._timing_max_dev = _def_timing_max_dev
self._differential = differential
if self._samples_per_symbol < 2:
raise TypeError, ("sbp must be >= 2, is %d" %
self._samples_per_symbol)
arity = pow(2, self.bits_per_symbol())
nfilts = 32
ntaps = 11 * int(self._samples_per_symbol * nfilts)
# Automatic gain control
self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
# Frequency correction
fll_ntaps = 55
self.freq_recov = digital_swig.fll_band_edge_cc(
self._samples_per_symbol, self._excess_bw, fll_ntaps,
self._freq_bw)
# symbol timing recovery with RRC data filter
taps = gr.firdes.root_raised_cosine(nfilts,
nfilts * self._samples_per_symbol,
1.0, self._excess_bw, ntaps)
self.time_recov = gr.pfb_clock_sync_ccf(self._samples_per_symbol,
self._timing_bw, taps, nfilts,
nfilts // 2,
self._timing_max_dev)
fmin = -0.25
fmax = 0.25
self.receiver = digital_swig.constellation_receiver_cb(
self._constellation, self._phase_bw, fmin, fmax)
# Do differential decoding based on phase change of symbols
if differential:
self.diffdec = gr.diff_decoder_bb(arity)
if gray_coded:
self.symbol_mapper = gr.map_bb(
mod_codes.invert_code(self._constellation.pre_diff_code()))
# unpack the k bit vector into a stream of bits
self.unpack = gr.unpack_k_bits_bb(self.bits_per_symbol())
if verbose:
self._print_verbage()
if log:
self._setup_logging()
# Connect and Initialize base class
blocks = [
self, self.agc, self.freq_recov, self.time_recov, self.receiver
]
if differential:
blocks.append(self.diffdec)
if self._constellation.apply_pre_diff_code():
blocks.append(self.symbol_mapper)
blocks += [self.unpack, self]
self.connect(*blocks)
