Hello:
I have a USRP2 + WBX running with GNU Radio 3.3.0 on openSUSE 11.2.
I created a simple flowgraph using GRC, a Signal Source connected into a
USRP2 Sink, used to generate a tone. I’m trying to setup a timer in the
flowgraph so that every 2 seconds, the tone flip-flops between 3 kHz and
6 kHz. When I run it, I get a tone at 1 kHz that never changes (the
default tone freq from the parameter list). It seems that my signal
handler is never getting called. I copied my code below. Could anyone
tell me why is my signal handler never getting called? What am I doing
wrong here?
Thanks for your help.
#!/usr/bin/env python
##################################################
Gnuradio Python Flow Graph
Title: Tst Generate Tone
Generated: Mon Dec 6 01:19:50 2010
##################################################
from gnuradio import eng_notation
from gnuradio import gr
from gnuradio import usrp2
from gnuradio.eng_option import eng_option
from gnuradio.gr import firdes
from grc_gnuradio import wxgui as grc_wxgui
from optparse import OptionParser
import wx
import signal
import time
import datetime
timer_tick_cnt = 0
timer_interval = 2.0
class tst_generate_tone(grc_wxgui.top_block_gui):
def init(self, p_eth=“eth1”, p_freq_carrier=900.0e6,
p_freq_tone=1.0e3, p_interp=500):
grc_wxgui.top_block_gui.init(self, title=“Tst Generate Tone”)
##################################################
# Parameters
##################################################
self.p_eth = p_eth
self.p_freq_carrier = p_freq_carrier
self.p_freq_tone = p_freq_tone
self.p_interp = p_interp
##################################################
# Variables
##################################################
self.samp_rate = samp_rate = 100000000/p_interp
##################################################
# Blocks
##################################################
self.gr_sig_source_x_0 = gr.sig_source_c(samp_rate, gr.GR_COS_WAVE,
p_freq_tone, 0.4, 0)
self.usrp2_sink_xxxx_0 = usrp2.sink_32fc(p_eth)
self.usrp2_sink_xxxx_0.set_interp(p_interp)
self.usrp2_sink_xxxx_0.set_center_freq(p_freq_carrier)
self.usrp2_sink_xxxx_0.set_gain(0)
self.usrp2_sink_xxxx_0.config_mimo(usrp2.MC_WE_LOCK_TO_SMA)
##################################################
# Connections
##################################################
self.connect((self.gr_sig_source_x_0, 0), (self.usrp2_sink_xxxx_0,
0))
def set_p_eth(self, p_eth):
self.p_eth = p_eth
def set_p_freq_carrier(self, p_freq_carrier):
self.p_freq_carrier = p_freq_carrier
self.usrp2_sink_xxxx_0.set_center_freq(self.p_freq_carrier)
def set_p_freq_tone(self, p_freq_tone):
self.p_freq_tone = p_freq_tone
self.gr_sig_source_x_0.set_frequency(self.p_freq_tone)
def set_p_interp(self, p_interp):
self.p_interp = p_interp
self.set_samp_rate(100000000/self.p_interp)
self.usrp2_sink_xxxx_0.set_interp(self.p_interp)
def set_samp_rate(self, samp_rate):
self.samp_rate = samp_rate
self.gr_sig_source_x_0.set_sampling_freq(self.samp_rate)
def alarm_handler(signo, frame):
global timer_tick_cnt
print "timer tick count is ", timer_tick_cnt
timer_tick_cnt = timer_tick_cnt + 1
new_freq = ((timer_tick_cnt % 2) + 1) * 3000.0
tst_generate_tone.gr_sig_source_x_0.set_ffrequency(new_freq)
if name == ‘main’:
parser = OptionParser(option_class=eng_option, usage="%prog:
[options]")
parser.add_option("", “–p-eth”, dest=“p_eth”, type=“string”,
default=“eth1”,
help=“Set p_eth [default=%default]”)
parser.add_option("", “–p-freq-carrier”, dest=“p_freq_carrier”,
type=“eng_float”, default=eng_notation.num_to_str(900.0e6),
help=“Set p_freq_carrier [default=%default]”)
parser.add_option("", “–p-freq-tone”, dest=“p_freq_tone”,
type=“eng_float”, default=eng_notation.num_to_str(1.0e3),
help=“Set p_freq_tone [default=%default]”)
parser.add_option("", “–p-interp”, dest=“p_interp”, type=“intx”,
default=500,
help=“Set p_interp [default=%default]”)
(options, args) = parser.parse_args()
if gr.enable_realtime_scheduling() != gr.RT_OK:
print “Error: failed to enable realtime scheduling.”
signal.signal(signal.SIGALRM, alarm_handler)
signal.setitimer(signal.ITIMER_REAL, timer_interval, timer_interval)
tb = tst_generate_tone(p_eth=options.p_eth,
p_freq_carrier=options.p_freq_carrier, p_freq_tone=options.p_freq_tone,
p_interp=options.p_interp)
tb.Run(True)