diff options
Diffstat (limited to 'gr-digital/python/digital/gmsk.py')
| -rw-r--r-- | gr-digital/python/digital/gmsk.py | 38 |
1 files changed, 25 insertions, 13 deletions
diff --git a/gr-digital/python/digital/gmsk.py b/gr-digital/python/digital/gmsk.py index cf998391c6..68127119e6 100644 --- a/gr-digital/python/digital/gmsk.py +++ b/gr-digital/python/digital/gmsk.py @@ -14,6 +14,7 @@ # See gnuradio-examples/python/digital for examples from math import pi +from math import log as ln from pprint import pprint import inspect @@ -167,7 +168,7 @@ class gmsk_demod(gr.hier_block2): Args: samples_per_symbol: samples per baud (integer) gain_mu: controls rate of mu adjustment (float) - mu: fractional delay [0.0, 1.0] (float) + mu: unused but unremoved for backward compatibility (unused) omega_relative_limit: sets max variation in omega (float) freq_error: bit rate error as a fraction (float) verbose: Print information about modulator? (boolean) @@ -189,7 +190,6 @@ class gmsk_demod(gr.hier_block2): self._samples_per_symbol = samples_per_symbol self._gain_mu = gain_mu - self._mu = mu self._omega_relative_limit = omega_relative_limit self._freq_error = freq_error self._differential = False @@ -204,15 +204,27 @@ class gmsk_demod(gr.hier_block2): self._gain_omega = .25 * self._gain_mu * self._gain_mu # critically damped + self._damping = 1.0 + self._loop_bw = -ln((self._gain_mu + self._gain_omega)/(-2.0) + 1) # critically damped + self._max_dev = self._omega_relative_limit * self._samples_per_symbol + # Demodulate FM sensitivity = (pi / 2) / samples_per_symbol self.fmdemod = analog.quadrature_demod_cf(1.0 / sensitivity) # the clock recovery block tracks the symbol clock and resamples as needed. # the output of the block is a stream of soft symbols (float) - self.clock_recovery = digital.clock_recovery_mm_ff(self._omega, self._gain_omega, - self._mu, self._gain_mu, - self._omega_relative_limit) + self.clock_recovery = self.digital_symbol_sync_xx_0 = digital.symbol_sync_ff(digital.TED_MUELLER_AND_MULLER, + self._omega, + self._loop_bw, + self._damping, + 1.0, # Expected TED gain + self._max_dev, + 1, # Output sps + digital.constellation_bpsk().base(), + digital.IR_MMSE_8TAP, + 128, + []) # slice the floats at 0, outputting 1 bit (the LSB of the output byte) per sample self.slicer = digital.binary_slicer_fb() @@ -235,10 +247,10 @@ class gmsk_demod(gr.hier_block2): def _print_verbage(self): print("bits per symbol = %d" % self.bits_per_symbol()) - print("M&M clock recovery omega = %f" % self._omega) - print("M&M clock recovery gain mu = %f" % self._gain_mu) - print("M&M clock recovery mu = %f" % self._mu) - print("M&M clock recovery omega rel. limit = %f" % self._omega_relative_limit) + print("Symbol Sync M&M omega = %f" % self._omega) + print("Symbol Sync M&M gain mu = %f" % self._gain_mu) + print("M&M clock recovery mu (Unused) = %f" % self._mu) + print("Symbol Sync M&M omega rel. limit = %f" % self._omega_relative_limit) print("frequency error = %f" % self._freq_error) @@ -257,13 +269,13 @@ class gmsk_demod(gr.hier_block2): Adds GMSK demodulation-specific options to the standard parser """ parser.add_option("", "--gain-mu", type="float", default=_def_gain_mu, - help="M&M clock recovery gain mu [default=%default] (GMSK/PSK)") + help="Symbol Sync M&M gain mu [default=%default] (GMSK/PSK)") parser.add_option("", "--mu", type="float", default=_def_mu, - help="M&M clock recovery mu [default=%default] (GMSK/PSK)") + help="M&M clock recovery mu [default=%default] (Unused)") parser.add_option("", "--omega-relative-limit", type="float", default=_def_omega_relative_limit, - help="M&M clock recovery omega relative limit [default=%default] (GMSK/PSK)") + help="Symbol Sync M&M omega relative limit [default=%default] (GMSK/PSK)") parser.add_option("", "--freq-error", type="float", default=_def_freq_error, - help="M&M clock recovery frequency error [default=%default] (GMSK)") + help="Symbol Sync M&M frequency error [default=%default] (GMSK)") @staticmethod def extract_kwargs_from_options(options): |