diff options
| author | Ben Reynwar <ben@reynwar.net> | 2013-03-07 23:27:44 -0700 |
|---|---|---|
| committer | Ben Reynwar <ben@reynwar.net> | 2013-03-07 23:27:44 -0700 |
| commit | ae30f247616b6229fb304e30fecf3f82ae09dbf6 (patch) | |
| tree | 74c1d6cd8300b44b6280c56bc4ad257c40390b3e /gr-analog/python/analog/wfm_tx.py | |
| parent | e8b4e619479dd23d87c3aef042f2452f867a1e18 (diff) | |
analog: Enabling uninstalled python imports.
Diffstat (limited to 'gr-analog/python/analog/wfm_tx.py')
| -rw-r--r-- | gr-analog/python/analog/wfm_tx.py | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/gr-analog/python/analog/wfm_tx.py b/gr-analog/python/analog/wfm_tx.py new file mode 100644 index 0000000000..be662310db --- /dev/null +++ b/gr-analog/python/analog/wfm_tx.py @@ -0,0 +1,82 @@ +# +# Copyright 2005,2007,2012 Free Software Foundation, Inc. +# +# This file is part of GNU Radio +# +# GNU Radio is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3, or (at your option) +# any later version. +# +# GNU Radio is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with GNU Radio; see the file COPYING. If not, write to +# the Free Software Foundation, Inc., 51 Franklin Street, +# Boston, MA 02110-1301, USA. +# + +import math +from gnuradio import gr +from gnuradio import filter +from fm_emph import fm_preemph + +try: + from gnuradio import analog +except ImportError: + import analog_swig as analog + +class wfm_tx(gr.hier_block2): + def __init__(self, audio_rate, quad_rate, tau=75e-6, max_dev=75e3): + """ + Wide Band FM Transmitter. + + Takes a single float input stream of audio samples in the range [-1,+1] + and produces a single FM modulated complex baseband output. + + Args: + audio_rate: sample rate of audio stream, >= 16k (integer) + quad_rate: sample rate of output stream (integer) + tau: preemphasis time constant (default 75e-6) (float) + max_dev: maximum deviation in Hz (default 75e3) (float) + + quad_rate must be an integer multiple of audio_rate. + """ + gr.hier_block2.__init__(self, "wfm_tx", + gr.io_signature(1, 1, gr.sizeof_float), # Input signature + gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature + + # FIXME audio_rate and quad_rate ought to be exact rationals + audio_rate = int(audio_rate) + quad_rate = int(quad_rate) + + if quad_rate % audio_rate != 0: + raise ValueError, "quad_rate is not an integer multiple of audio_rate" + + + do_interp = audio_rate != quad_rate + + if do_interp: + interp_factor = quad_rate / audio_rate + interp_taps = filter.optfir.low_pass(interp_factor, # gain + quad_rate, # Fs + 16000, # passband cutoff + 18000, # stopband cutoff + 0.1, # passband ripple dB + 40) # stopband atten dB + + print "len(interp_taps) =", len(interp_taps) + self.interpolator = filter.interp_fir_filter_fff (interp_factor, interp_taps) + + self.preemph = fm_preemph(quad_rate, tau=tau) + + k = 2 * math.pi * max_dev / quad_rate + self.modulator = analog.frequency_modulator_fc (k) + + if do_interp: + self.connect(self, self.interpolator, self.preemph, self.modulator, self) + else: + self.connect(self, self.preemph, self.modulator, self) |