[Discuss-gnuradio] Beginner Question: python script error when doing con

Hello,

I am trying to create a python equivalent of tx_samples.cc -- to transmit samples captured with usrp2_rx_cfile.py. When running my program, I receive the following error:

Traceback (most recent call last):

File "./usrp2_tx_cfile.py", line 151, in <module>

tb = tx_cfile_block(options, filename)

File "./usrp2_tx_cfile.py", line 80, in __init__

self.connect(self._src, self._u);

File "/usr/lib/python2.6/dist-packages/gnuradio/gr/top_block.py", line 124, in connect

self._connect(points[i-1], points[i])

File "/usr/lib/python2.6/dist-packages/gnuradio/gr/top_block.py", line 130, in _connect

dst_block.basic_block(), dst_port)

File "/usr/lib/python2.6/dist-packages/gnuradio/gr/gnuradio_swig_py_runtime.py", line 1443, in connect

return _gnuradio_swig_py_runtime.gr_top_block_sptr_connect(*args)

ValueError: itemsize mismatch: file_source(2):0 using 2, usrp2_sink_16sc(1):0 using 4

From the error, it appears that the connect() call is failing, but I am not sure why.

This is what my usrp2_tx_cfile.py looks like.

Thank you for your help.

Ilya

#!/usr/bin/env python

# 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.

"""

Read samples from the USRP2 and write to file formatted as binary

outputs single precision complex float values or complex short values

(interleaved 16 bit signed short integers).

"""

from gnuradio import gr, eng_notation

from gnuradio import usrp2

from gnuradio.eng_option import eng_option

from optparse import OptionParser

import sys

n2s = eng_notation.num_to_str

class tx_cfile_block(gr.top_block):

def __init__(self, options, filename):

gr.top_block.__init__(self)

# Create a USRP2 source

if options.input_shorts:

self._u = usrp2.sink_16sc(options.interface, options.mac_addr)

#the last True is to restart the file when it is done

self._src = gr.file_source(gr.sizeof_short,filename,True)

else:

self._u = usrp2.sink_32fc(options.interface, options.mac_addr)

#the last True is to restart the file when it is done

self._src = gr.file_source(gr.sizeof_gr_complex, filename, True)

# Set transmitter interpolation rate

self._u.set_interp(options.interp)

# Set transmit daughterboard gain

if options.gain is None:

g = self._u.gain_range()

options.gain = float(g[0]+g[1])/2

print "Using mid-point gain of", options.gain, "(", g[0], "-", g[1], ")"

#set the gain

self.amp = 10 ** (options.gain / 20 )

self._u.set_gain(self.amp)

# Set transmit frequency

if options.lo_offset is not None:

self._u.set_lo_offset(options.lo_offset)

tr = self._u.set_center_freq(options.freq)

if tr == None:

sys.stderr.write('Failed to set center frequency\n')

raise SystemExit, 1

#set output rate

output_rate = self._u.dac_rate() / self._u.interp()

#Filter if bandwidth was specified

if options.bandwidth is None:

#self.connect(self._src, self.amp, self._u);

self.connect(self._src, self._u);

else:

lp_coeffs = gr.firdes.lowpass(

1, #gain

output_rate, #sampling frequency

options.bandwidth/2, #cutoff frequency

options.bandwidth/2) #transition width

#if samples are shorts, convert to floats to do filtering

if options.input_shorts:

self.s2c = gr.interleaved_short_to_complex();

self.lp = gr.fir_filter_ccf(1,lp_coeffs)

self.c2s = gr.complex_to_interleaved_short()

self.connect(self._src, self.s2c, self.lp, self.amp, self.c2s,

self._u)

else:

self.lp = gr.fir_filter_ccf(1,lp_coeffs)

self.connect(self._src, self.lp, self.amp, self._u)

if options.verbose:

print "Network interface:", options.interface

print "USRP2 address:", self._u.mac_addr()

print "Using TX d'board id 0x%04X" % (self._u.daughterboard_id(),)

print "Tx gain:", options.gain

print "Tx baseband frequency:", n2s(tr.baseband_freq)

print "Tx DDC frequency:", n2s(tr.dxc_freq)

print "Tx residual frequency:", n2s(tr.residual_freq)

print "Tx interpolation rate:", options.interp

print "Tx sample rate:", n2s(output_rate)

if options.input_shorts:

print "Writing 16-bit complex shorts"

else:

print "Writing 32-bit complex floats"

print "Output filename:", filename

def get_options():

usage="%prog: [options] input_filename"

parser = OptionParser(option_class=eng_option, usage=usage)

parser.add_option("-e", "--interface", type="string", default="eth0",

help="use specified Ethernet interface [default=%default]")

parser.add_option("-m", "--mac-addr", type="string", default="",

help="use USRP2 at specified MAC address [default=None]")

parser.add_option("-i", "--interp", type="int", default=32,

help="set fgpa interpolation rate to INTERP [default=%default]")

parser.add_option("-f", "--freq", type="eng_float", default=None,

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( "-s","--input-shorts", action="" default=False,

help="input interleaved shorts instead of complex floats")

parser.add_option( "-b","--bandwidth", type="eng_float", default=None,

help="bandwidth of signal to transmit [default=no filtering]")

parser.add_option("-v", "--verbose", action="" default=False,

help="verbose output")

parser.add_option("", "--lo-offset", type="eng_float", default=None,

help="set daughterboard LO offset to OFFSET [default=hw default]")

(options, args) = parser.parse_args ()

if len(args) != 1:

parser.print_help()

raise SystemExit, 1

if options.freq is None:

parser.print_help()

sys.stderr.write('You must specify the frequency with -f FREQ\n');

raise SystemExit, 1

return (options, args[0])

if __name__ == '__main__':

(options, filename) = get_options()

tb = tx_cfile_block(options, filename)

try:

tb.run()

except KeyboardInterrupt:

pass

From:	Chukhman, Ilya A.
Subject:	[Discuss-gnuradio] Beginner Question: python script error when doing connect()
Date:	Wed, 16 Sep 2009 15:09:54 -0400