7/15/2019 · Excess BW Root-raised cosine (RRC) filter excess bandwidth (float) Verbose Print information about modulator? (boolean) Log Log modulation data to files? (boolean) Example Flowgraph . This flowgraph modulates random bits with 8-PSK.
By increasing the Excess BW parameter, number of points that appear at the edges decrease. We can increase Excess BW to 1. For Excess bandwidth > 1, the constellation diagram distorts , constellation points that are the tips of the rhombus are getting closer to the center.
excess _bw0 = 0.35: excess _bw1 = 0.22: sps = 4: loop_ bw = cmath. pi / 100.0: nfilts = 32: init_phase = nfilts / 2: max_rate_deviation = 0.5: osps = 1: ntaps = 11 * int (sps * nfilts) taps = filter. firdes. root_raised_cosine (nfilts, nfilts * sps, 1.0, excess _bw0, ntaps) self. test = digital. pfb_clock_sync_ccf (sps, loop_ bw , taps, nfilts, init_phase, max_rate_deviation, osps), self. _ excess _ bw = excess _ bw : self. _differential = differential # Only apply a predifferential coding if the constellation also supports it. self. pre_diff_code = pre_diff_code and self. _constellation. apply_pre_diff_code if self. _samples_per_symbol = 2, is %f % self. _samples_per_symbol) arity = pow (2, self. bits_per_symbol ()), It looks like your modulator has an excess BW of 0.35 (based on the pulse shaping filter used) which I believe means the occupied bandwidth would be the symbol rate (which is half your data rate) * 1.35. $endgroup$ – Dan Boschen Oct 22 ’19 at 0:13, 7/9/2020 · – name: excess _ bw : id: variable: parameters: comment: ” value: ‘0.35’ states: bus_sink: false: bus_source: false: bus_structure: null: coordinate: [416, 20.0] rotation: 0: state: enabled – name:.
digital.fll_band_edge_cc(self._samples_per_symbol, self._ excess _ bw , fll_ntaps, self._freq_ bw )./ Furthermore, I can find the timing recovery by polyphase filterbanks approach, through /self.time_recov = digital.pfb_clock_sync_ccf(self._samples_per_symbol,self._timing_ bw , taps,nfilts, nfilts//2, self._timing_max_dev) /, from gnuradio import gr, blocks, digital, analog, filter: from gnuradio . filter import firdes: import mapper: sps = 8: ebw = 0.35: class transmitter_mapper (gr. hier_block2): def __init__ (self, modtype, symvals, txname, samples_per_symbol = 2, excess _ bw .
digital: addresses issue gnuradio #890 . The set_taps was redone a while ago to better handle the differential taps as well as the normal ones, but this made externally resetting them impossible. Adding a new update_taps function to properly handle this case so …
