Modifications in benchmark_rx.py for USRP2


#1

Hi,

I have been trying to use USRP2 as a receiver and USRP1 as a
transmitter.
The benchmark_tx.py file is working well for USRP1 but I did some
modifications to benchmark_rx.py so that it can work on USRP2. But it
didnt
worked out. Can anyone help me with this modifcations so that I can
establish communication between USRP1 and USRP2. Thanks in advance.

View this message in context:
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#2

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Smith L. wrote:

Hi,

I have been trying to use USRP2 as a receiver and USRP1 as a transmitter.
The benchmark_tx.py file is working well for USRP1 but I did some
modifications to benchmark_rx.py so that it can work on USRP2. But it didnt
worked out. Can anyone help me with this modifcations so that I can
establish communication between USRP1 and USRP2. Thanks in advance.

I was finally able to dig up the versions I used a while back for this.
I don’t recall if the transmit side really worked, but the receive-side
certainly should.
You’ll want to copy/rename the original receive_path.py and
transmit_path.py, and replace them with the usrp2-versions, and
tunnel_usrp2.py can be used as-is (although - again, I’m not certain the
transmit-portion was working - although it gave no obvious errors).
Good luck!
Doug


Doug G.
Research Assistant
Communications and Signal Processing Lab
Oklahoma State University
http://cspl.okstate.edu
removed_email_address@domain.invalid
removed_email_address@domain.invalid
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#3

Smith L. wrote:

Hi,

I have been trying to use USRP2 as a receiver and USRP1 as a transmitter.
The benchmark_tx.py file is working well for USRP1 but I did some
modifications to benchmark_rx.py so that it can work on USRP2. But it didnt
worked out. Can anyone help me with this modifcations so that I can
establish communication between USRP1 and USRP2. Thanks in advance.

You have to watch out for the different sample rates. When you set the
sample rate in benchmark_tx/rx, it finds the closest sampling rate it
can get through the interpolation/decimation factor in the USRP. Since
the USRP and USRP2 have different speed DACs/ADCs, the exact values are
going to be different.

Run both with the -v option to see what the actual sample rate both the
tx and rx side are using. To fix this, either try to find a rate that
works for both USRP and USRP2, or, and this is a better solution, use a
blks2.rational_resampler_ccf to resample to achieve closer sampling
rates in both tx and rx.

Tom


#4

Hi Tom,

I tried it out but its not working. I am always getting an S which means
overrun. I am attaching the all the files that I have used to make USRP2
work as receiver. I have made no changes to benchmark_tx.py as it is
used
for USRP1 and its working correctly.

benchmark_rx.py:

#!/usr/bin/env python

Copyright 2005,2006,2007 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 usrp2
from gnuradio import eng_notation
from gnuradio.eng_option import eng_option
from optparse import OptionParser

import random
import struct
import sys

from current dir

from receive_path_usrp2 import receive_path
import fusb_options

#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)
self.rxpath = receive_path(demodulator, rx_callback, options)
self.connect(self.rxpath)

/////////////////////////////////////////////////////////////////////////////

main

/////////////////////////////////////////////////////////////////////////////

global n_rcvd, n_right

def main():
global n_rcvd, n_right

n_rcvd = 0
n_right = 0

def rx_callback(ok, payload):
    global n_rcvd, n_right
    (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)


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()),))

receive_path.add_options(parser, expert_grp)

for mod in demods.values():
    mod.add_options(expert_grp)

fusb_options.add_options(expert_grp)
(options, args) = parser.parse_args ()

if len(args) != 0:
    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

if name == ‘main’:
try:
main()
except KeyboardInterrupt:
pass

receive_path.py:

#!/usr/bin/env python

Copyright 2005,2006,2007 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, blks2
from gnuradio import usrp2
from gnuradio import eng_notation
import copy
import sys

from current dir

from pick_bitrate import pick_rx_bitrate

/////////////////////////////////////////////////////////////////////////////

receive path

/////////////////////////////////////////////////////////////////////////////

class receive_path(gr.hier_block2):
def init(self, demod_class, rx_callback, options):

gr.hier_block2.init(self, “receive_path”,
gr.io_signature(0, 0, 0), # Input
signature
gr.io_signature(0, 0, 0)) # Output
signature

    options = copy.copy(options)    # make a copy so we can

destructively modify

    self._interface          = options.interface           # the 

USRP
board attached
self._mac_addr = options.mac_addr
self._verbose = options.verbose
self._rx_freq = options.rx_freq # receiver’s
center frequency
self._rx_gain = options.rx_gain # receiver’s
gain
#self._rx_subdev_spec = options.rx_subdev_spec #
daughterboard
to use
self._bitrate = options.bitrate # desired bit
rate
self._decim = options.decim # Decimating
rate
for the USRP (prelim)
self._samples_per_symbol = options.samples_per_symbol # desired
samples/symbol
self._fusb_block_size = options.fusb_block_size # usb info
for
USRP
self._fusb_nblocks = options.fusb_nblocks # usb info
for
USRP

    self._rx_callback   = rx_callback      # this callback is fired 

when
there’s a packet available
self._demod_class = demod_class # the demodulator_class
we’re
using

    if self._rx_freq is None:
        sys.stderr.write("-f FREQ or --freq FREQ or --rx-freq FREQ 

must
be specified\n")
raise SystemExit

    # Set up USRP source; also adjusts decim, samples_per_symbol, 

and
bitrate
self._setup_usrp_source()

    g = self.u.gain_range()
    if options.show_rx_gain_range:
        print "Rx Gain Range: minimum = %g, maximum = %g, step size 

=
%g"
% (g[0], g[1], g[2])

    self.set_gain(options.rx_gain)

    self.set_auto_tr(True)                 # enable Auto

Transmit/Receive switching

    # Set RF frequency
    ok = self.set_freq(self._rx_freq)
    if not ok:
        print "Failed to set Rx frequency to %s" %

(eng_notation.num_to_str(self._rx_freq))
raise ValueError, eng_notation.num_to_str(self._rx_freq)

    # copy the final answers back into options for use by 

demodulator
options.samples_per_symbol = self._samples_per_symbol
options.bitrate = self._bitrate
options.decim = self._decim

    # Get demod_kwargs
    demod_kwargs =

self._demod_class.extract_kwargs_from_options(options)

Fix USRP2 -> USRP1 scaling

self.scale = gr.multiply_const_cc(32768)
# Design filter to get actual channel we want
sw_decim = 1
chan_coeffs = gr.firdes.low_pass (1.0, # gain
sw_decim *
self._samples_per_symbol, # sampling rate
1.0, #
midpoint
of trans. band
0.5, # width
of
trans. band
gr.firdes.WIN_HANN) # filter
type

    # 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 = \
        blks2.demod_pkts(self._demod_class(**demod_kwargs),
                         access_code=None,
                         callback=self._rx_callback,
                         threshold=-1)

    # Carrier Sensing Blocks
    alpha = 0.001
    thresh = 30   # in dB, will have to adjust

    if options.log_rx_power == True:
        self.probe = gr.probe_avg_mag_sqrd_cf(thresh,alpha)
        self.power_sink = gr.file_sink(gr.sizeof_float, 

“rxpower.dat”)
self.connect(self.chan_filt, self.probe, self.power_sink)
else:
self.probe = gr.probe_avg_mag_sqrd_c(thresh,alpha)
self.connect(self.chan_filt, self.probe)

    # Display some information about the setup
    if self._verbose:
        self._print_verbage()

    self.connect(self.u, self.scale, self.chan_filt,

self.packet_receiver)

def _setup_usrp_source(self):
    self.u = usrp2.source_32fc (self._interface, self._mac_addr)
    adc_rate = self.u.adc_rate()

    # derive values of bitrate, samples_per_symbol, and decim from

desired info
(self._bitrate, self._samples_per_symbol, self._decim) =
pick_rx_bitrate(self._bitrate,
self._demod_class.bits_per_symbol(),
self._samples_per_symbol, self._decim,
adc_rate)

    self.u.set_decim(self._decim)

    # determine the daughterboard subdevice we're using
    #if self._rx_subdev_spec is None:
    #    self._rx_subdev_spec = usrp.pick_rx_subdevice(self.u)
    #self.subdev = usrp.selected_subdev(self.u, 

self._rx_subdev_spec)

    #self.u.set_mux(usrp.determine_rx_mux_value(self.u,

self._rx_subdev_spec))

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.set_center_freq(target_freq)
    if r:
        return True

    return False

def set_gain(self, gain):
    """
    Sets the analog gain in the USRP
    """
    if gain is None:
        r = self.u.gain_range()
        gain = (r[0] + r[1])/2               # set gain to midpoint
    self.gain = gain
    return self.u.set_gain(gain)

def set_auto_tr(self, enable):
    #return self.u.set_auto_tr(enable)

return

def bitrate(self):
    return self._bitrate

def samples_per_symbol(self):
    return self._samples_per_symbol

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)


def add_options(normal, expert):
    """
    Adds receiver-specific options to the Options Parser
    """
    add_freq_option(normal)
    if not normal.has_option("--bitrate"):
        normal.add_option("-r", "--bitrate", type="eng_float",

default=None,
help=“specify bitrate. samples-per-symbol
and
interp/decim will be derived.”)
normal.add_option("-e", “–interface”, type=“string”,
default=“eth0”,
help=“select Ethernet interface, default is
eth0”)
normal.add_option("-m", “–mac-addr”, type=“string”, default="",
help=“select USRP by MAC address, default is
auto-select”)
#normal.add_option("-R", “–rx-subdev-spec”, type=“subdev”,
default=None,
# help=“select USRP Rx side A or B”)
normal.add_option("", “–rx-gain”, type=“eng_float”,
default=None,
metavar=“GAIN”,
help=“set receiver gain in dB
[default=midpoint].
See also --show-rx-gain-range”)
normal.add_option("", “–show-rx-gain-range”,
action=“store_true”,
default=False,
help=“print min and max Rx gain available on
selected daughterboard”)
normal.add_option("-v", “–verbose”, action=“store_true”,
default=False)
expert.add_option("-S", “–samples-per-symbol”, type=“int”,
default=None,
help=“set samples/symbol [default=%default]”)
expert.add_option("", “–rx-freq”, type=“eng_float”,
default=None,
help=“set Rx frequency to FREQ
[default=%default]”, metavar=“FREQ”)
expert.add_option("-d", “–decim”, type=“intx”, default=None,
help=“set fpga decimation rate to DECIM
[default=%default]”)
expert.add_option("", “–log”, action=“store_true”,
default=False,
help=“Log all parts of flow graph to files
(CAUTION: lots of data)”)
expert.add_option("", “–log-rx-power”, action=“store_true”,
default=False,
help=“Log receive signal power to file
(CAUTION:
lots of data)”)

# Make a static method to call before instantiation
add_options = staticmethod(add_options)


def _print_verbage(self):
    """
    Prints information about the receive path
    """
    print "\nReceive Path:"
    print "Using RX d'board %s"    % (self.u.daughterboard_id(),)
    print "Rx gain:         %g"    % (self.gain,)
    print "modulation:      %s"    % (self._demod_class.__name__)
    print "bitrate:         %sb/s" %

(eng_notation.num_to_str(self._bitrate))
print “samples/symbol: %3d” % (self._samples_per_symbol)
print “decim: %3d” % (self._decim)
print “Rx Frequency: %s” %
(eng_notation.num_to_str(self._rx_freq))
# print “Rx Frequency: %f” % (self._rx_freq)

def __del__(self):
    # Avoid weak reference error
    #del self.subdev

return

def add_freq_option(parser):
“”"
Hackery that has the -f / --freq option set both tx_freq and rx_freq
“”"
def freq_callback(option, opt_str, value, parser):
parser.values.rx_freq = value
parser.values.tx_freq = value

if not parser.has_option('--freq'):
    parser.add_option('-f', '--freq', type="eng_float",
                      action="callback", callback=freq_callback,
                      help="set Tx and/or Rx frequency to FREQ

[default=%default]",
metavar=“FREQ”)

tunnel_usrp2.py:

#!/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 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.

/////////////////////////////////////////////////////////////////////////////

This code sets up up a virtual ethernet interface (typically gr0),

and relays packets between the interface and the GNU Radio PHY+MAC

What this means in plain language, is that if you’ve got a couple

of USRPs on different machines, and if you run this code on those

machines, you can talk between them using normal TCP/IP networking.

/////////////////////////////////////////////////////////////////////////////

from gnuradio import gr, gru, modulation_utils
from gnuradio import usrp2
from gnuradio import eng_notation
from gnuradio.eng_option import eng_option
from optparse import OptionParser

import random
import time
import struct
import sys
import os

from current dir

from transmit_path import transmit_path
from receive_path import receive_path
import fusb_options

#print os.getpid()
#raw_input(‘Attach and press enter’)

/////////////////////////////////////////////////////////////////////////////

Use the Universal TUN/TAP device driver to move packets to/from

kernel

See /usr/src/linux/Documentation/networking/tuntap.txt

/////////////////////////////////////////////////////////////////////////////

Linux specific…

TUNSETIFF ifr flags from <linux/tun_if.h>

IFF_TUN = 0x0001 # tunnel IP packets
IFF_TAP = 0x0002 # tunnel ethernet frames
IFF_NO_PI = 0x1000 # don’t pass extra packet info
IFF_ONE_QUEUE = 0x2000 # beats me :wink:

def open_tun_interface(tun_device_filename):
from fcntl import ioctl

mode = IFF_TAP | IFF_NO_PI
TUNSETIFF = 0x400454ca

tun = os.open(tun_device_filename, os.O_RDWR)
ifs = ioctl(tun, TUNSETIFF, struct.pack("16sH", "gr%d", mode))
ifname = ifs[:16].strip("\x00")
return (tun, ifname)

/////////////////////////////////////////////////////////////////////////////

the flow graph

/////////////////////////////////////////////////////////////////////////////

class my_top_block(gr.top_block):

def __init__(self, mod_class, demod_class,
             rx_callback, options):

    gr.top_block.__init__(self)
    self.txpath = transmit_path(mod_class, options)
    self.rxpath = receive_path(demod_class, rx_callback, options)

self.connect(self.txpath);
self.connect(self.rxpath);

def send_pkt(self, payload='', eof=False):
    return self.txpath.send_pkt(payload, eof)

def carrier_sensed(self):
    """
    Return True if the receive path thinks there's carrier
    """
    return self.rxpath.carrier_sensed()

/////////////////////////////////////////////////////////////////////////////

Carrier Sense MAC

/////////////////////////////////////////////////////////////////////////////

class cs_mac(object):
“”"
Prototype carrier sense MAC

Reads packets from the TUN/TAP interface, and sends them to the PHY.
Receives packets from the PHY via phy_rx_callback, and sends them
into the TUN/TAP interface.

Of course, we're not restricted to getting packets via TUN/TAP, this
is just an example.
"""
def __init__(self, tun_fd, verbose=False):
    self.tun_fd = tun_fd       # file descriptor for TUN/TAP 

interface
self.verbose = verbose
self.tb = None # top block (access to PHY)

def set_top_block(self, tb):
    self.tb = tb

def phy_rx_callback(self, ok, payload):
    """
    Invoked by thread associated with PHY to pass received packet 

up.

    @param ok: bool indicating whether payload CRC was OK
    @param payload: contents of the packet (string)
    """
    if self.verbose:
        print "Rx: ok = %r  len(payload) = %4d" % (ok, len(payload))
    if ok:
        os.write(self.tun_fd, payload)

def main_loop(self):
    """
    Main loop for MAC.
    Only returns if we get an error reading from TUN.

    FIXME: may want to check for EINTR and EAGAIN and reissue read
    """
    min_delay = 0.001               # seconds

    while 1:
        payload = os.read(self.tun_fd, 10*1024)
        if not payload:
            self.tb.send_pkt(eof=True)
            break

        if self.verbose:
            print "Tx: len(payload) = %4d" % (len(payload),)

        delay = min_delay
        while self.tb.carrier_sensed():
            sys.stderr.write('B')
            time.sleep(delay)
            if delay < 0.050:
                delay = delay * 2       # exponential back-off

        self.tb.send_pkt(payload)

/////////////////////////////////////////////////////////////////////////////

main

/////////////////////////////////////////////////////////////////////////////

def main():

mods = modulation_utils.type_1_mods()
demods = modulation_utils.type_1_demods()

parser = OptionParser (option_class=eng_option,

conflict_handler=“resolve”)
expert_grp = parser.add_option_group(“Expert”)

parser.add_option("-m", "--modulation", type="choice",

choices=mods.keys(),
default=‘gmsk’,
help=“Select modulation from: %s
[default=%%default]”
% (’, '.join(mods.keys()),))

parser.add_option("-v","--verbose", action="store_true", 

default=False)
expert_grp.add_option("-c", “–carrier-threshold”, type=“eng_float”,
default=30,
help=“set carrier detect threshold (dB)
[default=%default]”)
expert_grp.add_option("","–tun-device-filename",
default="/dev/net/tun",
help=“path to tun device file
[default=%default]”)

transmit_path.add_options(parser, expert_grp)
receive_path.add_options(parser, expert_grp)

for mod in mods.values():
    mod.add_options(expert_grp)

for demod in demods.values():
    demod.add_options(expert_grp)

fusb_options.add_options(expert_grp)

(options, args) = parser.parse_args ()
if len(args) != 0:
    parser.print_help(sys.stderr)
    sys.exit(1)

if options.rx_freq is None or options.tx_freq is None:
    sys.stderr.write("You must specify -f FREQ or --freq FREQ\n")
    parser.print_help(sys.stderr)
    sys.exit(1)

# open the TUN/TAP interface
(tun_fd, tun_ifname) = 

open_tun_interface(options.tun_device_filename)

# Attempt to enable realtime scheduling
r = gr.enable_realtime_scheduling()
if r == gr.RT_OK:
    realtime = True
else:
    realtime = False
    print "Note: failed to enable realtime scheduling"


# If the user hasn't set the fusb_* parameters on the command line,
# pick some values that will reduce latency.

if options.fusb_block_size == 0 and options.fusb_nblocks == 0:
    if realtime:                        # be more aggressive
        options.fusb_block_size = gr.prefs().get_long('fusb',

‘rt_block_size’, 1024)
options.fusb_nblocks = gr.prefs().get_long(‘fusb’,
‘rt_nblocks’, 16)
else:
options.fusb_block_size = gr.prefs().get_long(‘fusb’,
‘block_size’, 4096)
options.fusb_nblocks = gr.prefs().get_long(‘fusb’,
‘nblocks’,
16)

#print "fusb_block_size =", options.fusb_block_size
#print "fusb_nblocks    =", options.fusb_nblocks

# instantiate the MAC
mac = cs_mac(tun_fd, verbose=True)


# build the graph (PHY)
tb = my_top_block(mods[options.modulation],
                  demods[options.modulation],
                  mac.phy_rx_callback,
                  options)

mac.set_top_block(tb)    # give the MAC a handle for the PHY

if tb.txpath.bitrate() != tb.rxpath.bitrate():
    print "WARNING: Transmit bitrate = %sb/sec, Receive bitrate =

%sb/sec" % (
eng_notation.num_to_str(tb.txpath.bitrate()),
eng_notation.num_to_str(tb.rxpath.bitrate()))

print "modulation:     %s"   % (options.modulation,)
print "freq:           %s"      %

(eng_notation.num_to_str(options.tx_freq))
print “bitrate: %sb/sec” %
(eng_notation.num_to_str(tb.txpath.bitrate()),)
print “samples/symbol: %3d” % (tb.txpath.samples_per_symbol(),)
#print “interp: %3d” % (tb.txpath.interp(),)
#print “decim: %3d” % (tb.rxpath.decim(),)

tb.rxpath.set_carrier_threshold(options.carrier_threshold)
print "Carrier sense threshold:", options.carrier_threshold, "dB"

print
print "Allocated virtual ethernet interface: %s" % (tun_ifname,)
print "You must now use ifconfig to set its IP address. E.g.,"
print
print "  $ sudo ifconfig %s 192.168.200.1" % (tun_ifname,)
print
print "Be sure to use a different address in the same subnet for 

each
machine."
print

tb.start()    # Start executing the flow graph (runs in separate

threads)

mac.main_loop()    # don't expect this to return...

tb.stop()     # but if it does, tell flow graph to stop.
tb.wait()     # wait for it to finish

if name == ‘main’:
try:
main()
except KeyboardInterrupt:
pass

Please let me know if I am missing out something in the code. Also can
you
let me know where am I suppose to use blks2.rational_resampler_ccf in
the
code. Thanks in advance.

With regards,
Smith

Tom R. wrote:

blks2.rational_resampler_ccf to resample to achieve closer sampling


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