diff options
Diffstat (limited to 'gr-digital/python/generic_mod_demod.py')
| -rw-r--r-- | gr-digital/python/generic_mod_demod.py | 73 |
1 files changed, 33 insertions, 40 deletions
diff --git a/gr-digital/python/generic_mod_demod.py b/gr-digital/python/generic_mod_demod.py index f252af13b..b5c727058 100644 --- a/gr-digital/python/generic_mod_demod.py +++ b/gr-digital/python/generic_mod_demod.py @@ -29,6 +29,7 @@ from gnuradio import gr from modulation_utils2 import extract_kwargs_from_options_for_class from utils import mod_codes import digital_swig +import math # default values (used in __init__ and add_options) _def_samples_per_symbol = 2 @@ -37,13 +38,12 @@ _def_verbose = False _def_log = False # Frequency correction -_def_freq_alpha = 0.010 +_def_freq_bw = 2*math.pi/100.0 # Symbol timing recovery -_def_timing_alpha = 0.100 -_def_timing_beta = 0.010 +_def_timing_bw = 2*math.pi/100.0 _def_timing_max_dev = 1.5 # Fine frequency / Phase correction -_def_phase_alpha = 0.1 +_def_phase_bw = 2*math.pi/100.0 # Number of points in constellation _def_constellation_points = 16 # Whether differential coding is used. @@ -77,6 +77,7 @@ class generic_mod(gr.hier_block2): differential=_def_differential, samples_per_symbol=_def_samples_per_symbol, excess_bw=_def_excess_bw, + gray_coded=True, verbose=_def_verbose, log=_def_log): """ @@ -88,9 +89,11 @@ class generic_mod(gr.hier_block2): @param constellation: determines the modulation type @type constellation: gnuradio.digital.gr_constellation @param samples_per_symbol: samples per baud >= 2 - @type samples_per_symbol: integer + @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 verbose: Print information about modulator? @type verbose: bool @param log: Log modulation data to files? @@ -206,10 +209,9 @@ class generic_demod(gr.hier_block2): samples_per_symbol=_def_samples_per_symbol, differential=_def_differential, excess_bw=_def_excess_bw, - freq_alpha=_def_freq_alpha, - timing_alpha=_def_timing_alpha, - timing_max_dev=_def_timing_max_dev, - phase_alpha=_def_phase_alpha, + freq_bw=_def_freq_bw, + timing_bw=_def_timing_bw, + phase_bw=_def_phase_bw, verbose=_def_verbose, log=_def_log): """ @@ -224,14 +226,12 @@ class generic_demod(gr.hier_block2): @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 timing_alpha: loop alpha gain for timing recovery - @type timing_alpha: float - @param timing_max_dev: timing loop maximum rate deviations - @type timing_max_dev: float - @param phase_alpha: loop filter gain in phase loop - @type phase_alphas: float + @param freq_bw: loop filter lock-in bandwidth + @type freq_bw: float + @param timing_bw: timing recoery 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? @@ -245,12 +245,10 @@ class generic_demod(gr.hier_block2): self._constellation = constellation.base() self._samples_per_symbol = samples_per_symbol self._excess_bw = excess_bw - self._phase_alpha = phase_alpha - self._freq_alpha = freq_alpha - self._freq_beta = 0.10*self._freq_alpha - self._timing_alpha = timing_alpha - self._timing_beta = _def_timing_beta - self._timing_max_dev=timing_max_dev + 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: @@ -258,26 +256,24 @@ class generic_demod(gr.hier_block2): 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 - self.bandwidth = 6.28 / 100.0 self.freq_recov = digital_swig.fll_band_edge_cc(self._samples_per_symbol, self._excess_bw, - 11*int(self._samples_per_symbol), - self.bandwidth) + ntaps, self._freq_bw) # symbol timing recovery with RRC data filter - nfilts = 32 - ntaps = 11 * int(self._samples_per_symbol*nfilts) - taps = gr.firdes.root_raised_cosine(nfilts, nfilts, - 1.0/float(self._samples_per_symbol), - self._excess_bw, ntaps) + 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_alpha, - taps, nfilts, nfilts/2, self._timing_max_dev) - self.time_recov.set_beta(self._timing_beta) + self._timing_bw, taps, + nfilts, nfilts/2, self._timing_max_dev) + self._phase_alpha = 0.1 self._phase_beta = 0.25 * self._phase_alpha * self._phase_alpha fmin = -0.25 fmax = 0.25 @@ -323,12 +319,9 @@ class generic_demod(gr.hier_block2): print "\nDemodulator:" print "bits per symbol: %d" % self.bits_per_symbol() print "RRC roll-off factor: %.2f" % self._excess_bw - print "FLL gain: %.2e" % self._freq_alpha - print "Timing alpha gain: %.2e" % self._timing_alpha - print "Timing beta gain: %.2e" % self._timing_beta - print "Timing max dev: %.2f" % self._timing_max_dev - print "Phase track alpha: %.2e" % self._phase_alpha - print "Phase track beta: %.2e" % self._phase_beta + print "FLL bandwidth: %.2e" % self._freq_bw + print "Timing bandwidth: %.2e" % self._timing_bw + print "Phase bandwidth: %.2e" % self._phase_bw def _setup_logging(self): print "Modulation logging turned on." |