I am using two TVRx modules on the same motherboard to write a 1 second
sample every minute for 30mins. theoretically I should have 60 sample
sets,
collectively.
I am able to write the first sample set succesfully but all writes after
that fail!
Please take a moment to look at what I may be doing wrong.
with thanks.
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class my_top_block(gr.top_block):
def __init__(self):
gr.top_block.__init__(self)
usage="%prog: [options] output_filename0 output_filename1 "
parser = OptionParser(option_class=eng_option, usage=usage)
parser.add_option("-R", "--rx-subdev-spec0", type="subdev",
default=None,
help=“first channel select USRP Rx side A or B
(default=A)”)
parser.add_option("-r", “–rx-subdev-spec1”, type=“subdev”,
default=None,
help=“second channel select USRP Rx side A or B
(default=A)”)
parser.add_option("-d", “–decim”, type=“int”, default=256,
help=“set fgpa decimation rate to DECIM
[default=%default]”)
parser.add_option("-f", “–freq”, type=“eng_float”,
default=100e6,
help=“set frequency to FREQ”, metavar=“FREQ”)
parser.add_option("-g", “–gain”, type=“eng_float”,
default=None,
help=“set gain in dB (default is midpoint)”)
parser.add_option("-N", “–nsamples”, type=“eng_float”,
default=9600000,
help=“number of samples to collect
[default=9600000]”)
parser.add_option("-t", “–time”, type=“eng_float”, default=0,
help=“length of recording in seconds
[default=0]”)
(options, args) = parser.parse_args ()
decim_rate = options.decim
if options.time:
options.nsamples = int(float(options.time) * 64e6 /
float(decim_rate))
else:
options.time = float(options.nsamples / (64e6 /
float(decim_rate)) )
if options.freq is None:
parser.print_help()
sys.stderr.write('You must specify the frequency with -f
FREQ\n’);
raise SystemExit, 1
# setup USRP source
self.u = usrp.source_c(decim_rate = options.decim, nchan = 2)
# set up daughterboard positions and subdevices
if options.rx_subdev_spec0 is None:
options.rx_subdev_spec0 = (0,0)
if options.rx_subdev_spec1 is None:
options.rx_subdev_spec1 = (1,0)
# determine the daughterboard subdevice we're using
self.subdev0 = usrp.selected_subdev(self.u,
options.rx_subdev_spec0)
self.subdev1 = usrp.selected_subdev(self.u,
options.rx_subdev_spec1)
#setup Mux
mux_val0 = usrp.determine_rx_mux_value(self.u,
options.rx_subdev_spec0)
mux_val1 = usrp.determine_rx_mux_value(self.u,
options.rx_subdev_spec1)
mux_val0 |= (mux_val1 << 8) & 0xff00
self.u.set_mux(mux_val0)
if options.gain is None:
# if no gain was specified, use the mid-point in dB
g0 = self.subdev0.gain_range()
g1 = self.subdev1.gain_range()
options.gain = float(g0[0]+g0[1])/2
self.subdev0.set_gain(options.gain)
self.subdev1.set_gain(options.gain)
ddc = -19.9e6
self.subdev = (self.subdev0, self.subdev1)
#Tune daughterboards
for n in range(2):
ok, baseband_freq = self.subdev[n].set_freq(options.freq)
print "baseband Freq is: %s" %
(eng_notation.num_to_str(baseband_freq))
dxc_freq, inverted = usrp.calc_dxc_freq(options.freq,
baseband_freq,
self.u.converter_rate())
print “dxc Freq is: %s” %
(eng_notation.num_to_str(dxc_freq))
print “ddc Freq is: %s” % (eng_notation.num_to_str(ddc))
self.u.set_rx_freq(n, ddc)
input_rate = self.u.adc_freq() / self.u.decim_rate()
print "Using RX d'board %s" % (self.subdev0.side_and_name(),)
print "Using RX d'board %s" % (self.subdev1.side_and_name(),)
print "USB sample rate: %s" %
(eng_notation.num_to_str(input_rate))
print “Freq is set to: %s” %
(eng_notation.num_to_str(options.freq))
print “Recording time is: %ss” % (options.time)
print “Mux value is: %x” % (mux_val0 & 65535)
self.num_samples = options.nsamples
#return (self, num_samples)
def __del__(self):
# Avoid weak reference error
del self.subdev
def write_file(self, file_num, file_size):
# deinterleave two channels from FPGA
self.di = gr.deinterleave(gr.sizeof_gr_complex)
self.skiphead0 = gr.skiphead(gr.sizeof_gr_complex, 1000)
self.skiphead1 = gr.skiphead(gr.sizeof_gr_complex, 1000)
self.head0 = gr.head(gr.sizeof_gr_complex, file_size)
self.head1 = gr.head(gr.sizeof_gr_complex, file_size)
self.dst0 = gr.file_sink(gr.sizeof_gr_complex, ('moda%s' %
file_num))
self.dst1 = gr.file_sink(gr.sizeof_gr_complex, (‘modb%s’ %
file_num))
# wire up the head of the chain
self.connect(self.u, self.di)
self.connect((self.di,0), self.skiphead0, self.head0, self.dst0)
self.connect((self.di,1), self.skiphead1, self.head1, self.dst1)
if name == ‘main’:
total_time = 3
t = 0
n_s = 0
tb = my_top_block()
n_s = tb.num_samples
try:
while t < total_time:
t = t+1
print "setup graph"
tb.write_file(t, n_s)
print "run graph"
tb.start()
#tb.run()
print "graph terminated"
print "sleep on"
time.sleep(60)
tb.stop()
tb.wait()
print "sleep off"
except KeyboardInterrupt:
pass
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