From 5d69a524f81f234b3fbc41d49ba18d6f6886baba Mon Sep 17 00:00:00 2001 From: jcorgan <jcorgan@221aa14e-8319-0410-a670-987f0aec2ac5> Date: Thu, 3 Aug 2006 04:51:51 +0000 Subject: Houston, we have a trunk. git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@3122 221aa14e-8319-0410-a670-987f0aec2ac5 --- gnuradio-examples/python/gmsk2/receive_path.py | 150 +++++++++++++++++++++++++ 1 file changed, 150 insertions(+) create mode 100644 gnuradio-examples/python/gmsk2/receive_path.py (limited to 'gnuradio-examples/python/gmsk2/receive_path.py') diff --git a/gnuradio-examples/python/gmsk2/receive_path.py b/gnuradio-examples/python/gmsk2/receive_path.py new file mode 100644 index 0000000000..505ff7c4d3 --- /dev/null +++ b/gnuradio-examples/python/gmsk2/receive_path.py @@ -0,0 +1,150 @@ +#!/usr/bin/env python +# +# Copyright 2005,2006 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 2, 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., 59 Temple Place - Suite 330, +# Boston, MA 02111-1307, USA. +# + +from gnuradio import gr, gru, blks +from gnuradio import usrp + +# from current dir +from pick_bitrate import pick_rx_bitrate + +# ///////////////////////////////////////////////////////////////////////////// +# receive path +# ///////////////////////////////////////////////////////////////////////////// + +class receive_path(gr.hier_block): + def __init__(self, fg, demod_class, rx_subdev_spec, + bitrate, decim, spb, + rx_callback, options, demod_kwargs): + + self.u = usrp.source_c (fusb_block_size=options.fusb_block_size, + fusb_nblocks=options.fusb_nblocks) + adc_rate = self.u.adc_rate() + + (self._bitrate, self._spb, self._decim) = \ + pick_rx_bitrate(bitrate, demod_class.bits_per_baud(), spb, decim, adc_rate) + + self.u.set_decim_rate(self._decim) + sw_decim = 1 + + if rx_subdev_spec is None: + rx_subdev_spec = usrp.pick_rx_subdevice(self.u) + self.subdev = usrp.selected_subdev(self.u, rx_subdev_spec) + print "Using RX d'board %s" % (self.subdev.side_and_name(),) + + self.u.set_mux(usrp.determine_rx_mux_value(self.u, rx_subdev_spec)) + + # Create filter to get actual channel we want + chan_coeffs = gr.firdes.low_pass (1.0, # gain + sw_decim * self._spb, # sampling rate + 1.0, # midpoint of trans. band + 0.1, # width of trans. band + gr.firdes.WIN_HANN) # filter type + + print "len(rx_chan_coeffs) =", len(chan_coeffs) + + # Decimating Channel filter + # complex in and out, float taps + self.chan_filt = gr.fft_filter_ccc(sw_decim, chan_coeffs) + #self.chan_filt = gr.fir_filter_ccf(sw_decim, chan_coeffs) + + # receiver + self.packet_receiver = \ + blks.demod_pkts(fg, + demod_class(fg, spb=self._spb, **demod_kwargs), + access_code=None, + callback=rx_callback, + threshold=-1) + + fg.connect(self.u, self.chan_filt, self.packet_receiver) + gr.hier_block.__init__(self, fg, None, None) + + g = self.subdev.gain_range() + #self.set_gain((g[0] + g[1])/2) # set gain to midpoint + self.set_gain(g[1]) # set gain to max + self.set_auto_tr(True) # enable Auto Transmit/Receive switching + + # Carrier Sensing Blocks + alpha = 0.001 + thresh = 30 # in dB, will have to adjust + self.probe = gr.probe_avg_mag_sqrd_c(thresh,alpha) + fg.connect(self.chan_filt, self.probe) + + def set_freq(self, target_freq): + """ + Set the center frequency we're interested in. + + @param target_freq: frequency in Hz + @rypte: bool + + Tuning is a two step process. First we ask the front-end to + tune as close to the desired frequency as it can. Then we use + the result of that operation and our target_frequency to + determine the value for the digital up converter. + """ + r = self.u.tune(0, self.subdev, target_freq) + if r: + return True + + return False + + def set_gain(self, gain): + if gain is None: + r = self.subdev.gain_range() + gain = (r[0] + r[1])/2 # set gain to midpoint + self.gain = gain + return self.subdev.set_gain(gain) + + def set_auto_tr(self, enable): + return self.subdev.set_auto_tr(enable) + + def bitrate(self): + return self._bitrate + + def spb(self): + return self._spb + + def decim(self): + return self._decim + + + def carrier_sensed(self): + """ + Return True if we think carrier is present. + """ + #return self.probe.level() > X + return self.probe.unmuted() + + def carrier_threshold(self): + """ + Return current setting in dB. + """ + return self.probe.threshold() + + def set_carrier_threshold(self, threshold_in_db): + """ + Set carrier threshold. + + @param threshold_in_db: set detection threshold + @type threshold_in_db: float (dB) + """ + self.probe.set_threshold(threshold_in_db) + -- cgit v1.2.3