Hi
I am new to python and I need to know about adding new blocks.
I modified the benchmark_tx and rx.py files, so that the receiver will
get the file from sender and store it in a txt file which is passed as
an arguement. I also added few lines of code so that the receiver
calculates the number of error bits in each packet it receives.
The program is as follows:
#!/usr/bin/env python
Copyright 2005,2006,2007,2009 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.
from gnuradio import gr, gru, modulation_utils
from gnuradio import usrp
from gnuradio import eng_notation
from gnuradio.eng_option import eng_option
from optparse import OptionParser
import random
import struct
import sys
import time
import binascii
from current dir
import usrp_receive_path
import operator
#import os
#print os.getpid()
#raw_input('Attach and press enter: ')
class my_top_block(gr.top_block):
def init(self, demodulator, rx_callback, options):
gr.top_block.init(self)
Set up receive path
self.rxpath = usrp_receive_path.usrp_receive_path(demodulator,
rx_callback, options)
self.connect(self.rxpath)
/////////////////////////////////////////////////////////////////////////////
main
/////////////////////////////////////////////////////////////////////////////
global n_rcvd, n_right
def main():
global n_rcvd, n_right, bi, pattern, a, x, t, coun, tbin, i, l, abin
n_rcvd = 0
n_right = 0
coun=l=0
#FILE = open(“payload.dat”, “a”)
def rx_callback(ok, payload):
global n_rcvd, n_right, coun, l
(pktno,) = struct.unpack(’!H’, payload[0:2])
n_rcvd += 1
if ok:
n_right += 1
print “ok = %5s pktno = %4d n_rcvd = %4d n_right = %4d” % (
ok, pktno, n_rcvd, n_right)
a =ord(payload[2:options.size])
abin=bin(a)[2:]
FILE.write(payload[2:options.size])
#a=ord(payload[2:options.size])
print ('a = ’ , a)
print(‘abin=’,abin)
x =ord(‘a’)
#print(‘x=b=’, x)
t= operator.xor(a,x)
#print(“t=”, t)
tbin= bin(t)[2:]
#print('tbin= ',tbin)
i=0
l=len(abin)+l
while i<len(tbin):
if tbin[i]==‘1’:
coun=coun+1
i=i+1
print(“total error bits so far=”,coun)
print(“total bits=”, l)
b=float(coun)/float(l)
print(“b=”,b)
demods = modulation_utils.type_1_demods()
Create Options Parser:
parser = OptionParser (option_class=eng_option,
conflict_handler=“resolve”)
expert_grp = parser.add_option_group(“Expert”)
parser.add_option("-m", “–modulation”, type=“choice”,
choices=demods.keys(),
default=‘gmsk’,
help=“Select modulation from: %s [default=%%default]”
% (’, '.join(demods.keys()),))
parser.add_option("-s", “–size”, type=“eng_float”, default=1500,
help=“set packet size [default=%default]”)
usrp_receive_path.add_options(parser, expert_grp)
for mod in demods.values():
mod.add_options(expert_grp)
(options, args) = parser.parse_args ()
filename = args[0];
FILE = open(filename, “a”)
if len(args) != 1:
parser.print_help(sys.stderr)
sys.exit(1)
if options.rx_freq is None:
sys.stderr.write(“You must specify -f FREQ or --freq FREQ\n”)
parser.print_help(sys.stderr)
sys.exit(1)
build the graph
tb = my_top_block(demods[options.modulation], rx_callback, options)
r = gr.enable_realtime_scheduling()
if r != gr.RT_OK:
print “Warning: Failed to enable realtime scheduling.”
tb.start() # start flow graph
tb.wait() # wait for it to finish
FILE.close()
if name == ‘main’:
try:
main()
except KeyboardInterrupt:
pass
I am now trying to find the received signal power in receiver node and
I found many websites mention this particulat piece of code to be
added to the program:
alpha = 0.001
thresh = 30 # in dB, will have to adjust
self.probe = gr.probe_avg_mag_sqrd_cf(thresh,alpha)
self.power_sink = gr.file_sink(gr.sizeof_float, “rxpower.dat”)
self.connect(self.probe, self.power_sink)
But I am unable to connect this probe to the rxpath. whenever i add code
like:
self.connect(self,self.probe) # connects the input block to
the power probe
self.connect(self.probe, self.rxpath)# connects the power block
to the rece
I get error like,
ValueError: port number 0 exceeds max of (none)
I think this is something related to the number of ports in some block
am trying to connect. Can anyone help me with this?