def __init__(self, channel_rate, threshold):
gr.hier_block2.__init__(self, "ppm_demod",
gr.io_signature(1, 1, gr.sizeof_gr_complex),
gr.io_signature(1, 1, 512))
chan_rate = 8000000 # Minimum sample rate
if channel_rate < chan_rate:
raise ValueError, "Invalid channel rate %d. Must be 8000000 sps or higher" % (channel_rate)
if channel_rate >= 10000000:
chan_rate = 10000000 # Higher Performance Receiver
# if rate is not supported then resample
if channel_rate != chan_rate:
interp = gru.lcm(channel_rate, chan_rate)/channel_rate
decim = gru.lcm(channel_rate, chan_rate)/chan_rate
self.RESAMP = rational_resampler_ccf(self, interp, decim)
# Calculate the leading edge threshold per sample time
leading_edge = risetime_threshold_db/(chan_rate/data_rate)
# Calculate the number of following samples above threshold needed to make a sample a valid pulse position
valid_pulse_position = 2
if chan_rate == 10000000:
valid_pulse_position = 3
# Demodulate AM with classic sqrt (I*I + Q*Q)
self.MAG = gr.complex_to_mag()
self.DETECT = air.ms_pulse_detect(leading_edge, threshold, valid_pulse_position) # Attack, Threshold, Pulsewidth
self.SYNC = air.ms_preamble(chan_rate)
self.FRAME = air.ms_framer(chan_rate)
self.BIT = air.ms_ppm_decode(chan_rate)
self.PARITY = air.ms_parity()
self.EC = air.ms_ec_brute()
if channel_rate != chan_rate:
# Resample the stream first
self.connect(self, self.RESAMP, self.MAG, self.DETECT)
else:
self.connect(self, self.MAG, self.DETECT)
self.connect((self.DETECT, 0), (self.SYNC, 0))
self.connect((self.DETECT, 1), (self.SYNC, 1))
self.connect((self.SYNC, 0), (self.FRAME, 0))
self.connect((self.SYNC, 1), (self.FRAME, 1))
self.connect((self.FRAME, 0), (self.BIT, 0))
self.connect((self.FRAME, 1), (self.BIT, 1))
self.connect(self.BIT, self.PARITY, self.EC, self)
def __init__(self, frame, panel, vbox, argv):
stdgui2.std_top_block.__init__(self, frame, panel, vbox, argv)
self.frame = frame
self.panel = panel
parser = OptionParser(option_class=eng_option)
parser.add_option("-R", "--rx-subdev-spec", type="subdev", default=None,
help="select USRP Rx side A or B (default=first one with a daughterboard)")
parser.add_option("-d", "--decim", type="int", default=8,
help="set fgpa decimation rate to DECIM [default=%default]")
parser.add_option("-f", "--freq", type="eng_float", default=1090.0,
help="set receive frequency to MHz [default=%default]", metavar="FREQ")
parser.add_option("-g", "--gain", type="eng_float", default=None,
help="set gain in dB (default is midpoint)")
parser.add_option("-8", "--width-8", action="store_true", default=False,
help="Enable 8-bit samples across USB")
parser.add_option("-n", "--frame-decim", type="int", default=1,
help="set oscope frame decimation factor to n [default=1]")
parser.add_option("-v", "--v-scale", type="eng_float", default=200,
help="set oscope initial V/div to SCALE [default=%default]")
parser.add_option("-t", "--t-scale", type="eng_float", default=24e-6,
help="set oscope initial s/div to SCALE [default=25us]")
parser.add_option("-T", "--thresh", type="int", default=10,
help="set valid pulse threshold to THRESH [default=%default]")
(options, args) = parser.parse_args()
if len(args) != 0:
parser.print_help()
sys.exit(1)
self.show_debug_info = True
options.freq *= 1e6
# build the graph
if options.decim < 8:
self.fpga_filename="std_4rx_0tx.rbf" #Min decimation of this firmware is 4. contains 4 Rx paths without halfbands and 0 tx paths.
self.u = usrp.source_c(decim_rate=options.decim, fpga_filename=self.fpga_filename)
else :
#standard fpga firmware "std_2rxhb_2tx.rbf" contains 2 Rx paths with halfband filters and 2 tx paths (the default) min decimation 8
self.u = usrp.source_c(decim_rate=options.decim)
if options.rx_subdev_spec is None:
options.rx_subdev_spec = pick_subdevice(self.u)
self.u.set_mux(usrp.determine_rx_mux_value(self.u, options.rx_subdev_spec))
if options.width_8:
width = 8
shift = 8
format = self.u.make_format(width, shift)
#print "format =", hex(format)
r = self.u.set_format(format)
#print "set_format =", r
# determine the daughterboard subdevice we're using
self.subdev = usrp.selected_subdev(self.u, options.rx_subdev_spec)
#self.subdev.set_bw(5e6) # only valid for dbsrx
chan_rate = 8000000
input_rate = self.u.adc_freq() / self.u.decim_rate()
if input_rate < chan_rate:
raise ValueError, "Invalid input rate %d. Must be 8000000 sps or higher" % (input_rate)
if input_rate >= 10000000:
chan_rate = 10000000 # Higher Performance Receiver
# if rate is not supported then resample
if input_rate != chan_rate:
raise Error, "Resampling Unsupported"
#interp = gru.lcm(input_rate, chan_rate)/input_rate
#decim = gru.lcm(input_rate, chan_rate)/chan_rate
#print interp, decim
#self.resamp = blks.rational_resampler_ccf(self, interp, decim)
# Calculate the leading edge threshold per sample time
leading_edge = risetime_threshold_db/(chan_rate/data_rate)
# The number of following samples above threshold needed to make a sample a valid pulse position
valid_pulse_position = 2
if chan_rate == 10000000:
valid_pulse_position = 3
self.mag = gr.complex_to_mag()
self.detect = air.ms_pulse_detect(leading_edge, options.thresh, valid_pulse_position)
self.sync = air.ms_preamble(chan_rate)
self.frame = air.ms_framer(chan_rate)
self.cvt = air.ms_cvt_float()
self.scope = scopesink2.scope_sink_f(self, panel, sample_rate=chan_rate,
frame_decim=options.frame_decim,
v_scale=options.v_scale,
t_scale=options.t_scale)
#if chan_rate == 10000000:
#self.connect(self.u, self.resamp, self.mag, self.detect)
#else :
self.connect(self.u, self.mag, self.detect)
self.connect((self.detect, 0), (self.sync, 0))
self.connect((self.detect, 1), (self.sync, 1))
self.connect((self.sync, 0), (self.frame, 0))
self.connect((self.sync, 1), (self.frame, 1))
self.connect((self.frame, 0), (self.cvt, 0))
self.connect((self.frame, 1), (self.cvt, 1))
self.connect((self.cvt, 0), (self.scope, 0))
self.connect((self.cvt, 1), (self.scope,1))
self.connect((self.cvt, 2), (self.scope,2))
self._build_gui(vbox)
# set initial values
if options.gain is None:
# if no gain was specified, use the mid-point in dB
g = self.subdev.gain_range()
options.gain = float(g[0]+g[1])/2
self.set_gain(options.gain)
if self.show_debug_info:
self.myform['decim'].set_value(self.u.decim_rate())
self.myform['fs@usb'].set_value(self.u.adc_freq() / self.u.decim_rate())
self.myform['dbname'].set_value(self.subdev.name())
self.myform['baseband'].set_value(0)
self.myform['ddc'].set_value(0)
if not(self.set_freq(options.freq)):
self._set_status_msg("Failed to set initial frequency")
