Eric Blossom wrote:
On Mon, Apr 30, 2007 at 02:17:38PM +1200, Jonas wrote:
Hello,
I have run into a problem using flow_graph stop(). To test the problem,
I wrote a quick test script that simply sinks a tone to the USRP
(test_tone.py).
Hi Jonas,
Can you send me the complete script off the list?
Hi Eric,
Thanks for your response! I have attached test_tone.py, which since my
last post I have checked and changed slightly, but the problem doesn't
seem to be there.
BTW, what are you really trying to accomplish?
I am developing a USRP Server computer that can be controlled from any
client computer, (clients run Matlab under Windows). Clients require the
ability to terminate running flow graphs, hence my requirement for stop().
To test the stop() functionality (independent of my threaded server code)
I am running test_tone.py in the python interpreter.
from test_tone import *
tone = test_tone()
tone.start()
The only way I can get the USRP to actually stop transmitting something is
to delete my instantiated test_tone object. Calling stop() stops the tone
but the USRP still transmits something (difference between actually being
off and pretending to be off is 40 dB).
Also, can you figure out how to get rid of this signature?
It's not appropriate for posting to what is obviously a public mailing
list.
I am sorry about the signature but unfortunately it is attached as it
leaves. Maybe I should setup an external email address.
Eric
Thanks for your help,
Jonas
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#!/usr/bin/env python
"""
Transmits a 800 Hz tone, as a narrow band FM signal.
"""
from gnuradio import gr
from gnuradio import usrp
from gnuradio import blks
from Numeric import convolve, array
class test_tone(gr.flow_graph):
def __init__(self):
gr.flow_graph.__init__(self)
tone_freq = 800
tx_freq = 440.1e6
tone = transmit_path(self, None, tone_freq)
tone.set_freq(tx_freq)
tone.set_enable(True)
class transmit_path(gr.hier_block):
def __init__(self, fg, subdev_spec, tone_freq):
self.u = usrp.sink_c ()
dac_rate = self.u.dac_rate();
self.if_rate = 320e3 # 320 kS/s
self.usrp_interp = int(dac_rate // self.if_rate)
self.u.set_interp_rate(self.usrp_interp)
self.sw_interp = 10
self.audio_rate = self.if_rate // self.sw_interp # 32 kS/s
self.audio_gain = 1
self.normal_gain = 500
self.audio = gr.sig_source_f (self.audio_rate, #
sample rate
gr.GR_SIN_WAVE, #
waveform type
tone_freq,
# frequency
1.0, #
amplitude
0) #
DC Offset
self.audio_amp = gr.multiply_const_ff(self.audio_gain)
lpf = gr.firdes.low_pass (1, # gain
self.audio_rate, #
sampling rate
3800, # low
pass cutoff freq
300, # width
of trans. band
gr.firdes.WIN_HANN) # filter
type
hpf = gr.firdes.high_pass (1, # gain
self.audio_rate, #
sampling rate
325, # low pass
cutoff freq
50, # width of
trans. band
gr.firdes.WIN_HANN) # filter
type
audio_taps = convolve(array(lpf),array(hpf))
self.audio_filt = gr.fir_filter_fff(1,audio_taps)
self.pl = blks.ctcss_gen_f(fg, self.audio_rate,123.0)
self.add_pl = gr.add_ff()
fg.connect(self.pl,(self.add_pl,1))
self.fmtx = blks.nbfm_tx(fg, self.audio_rate, self.if_rate)
self.amp = gr.multiply_const_cc (self.normal_gain)
# determine the daughterboard subdevice we're using
if subdev_spec is None:
subdev_spec = usrp.pick_tx_subdevice(self.u)
self.u.set_mux(usrp.determine_tx_mux_value(self.u,
subdev_spec))
self.subdev = usrp.selected_subdev(self.u, subdev_spec)
print "TX using", self.subdev.side_and_name()
fg.connect(self.audio, self.audio_amp, self.audio_filt,
(self.add_pl,0), self.fmtx, self.amp, self.u)
gr.hier_block.__init__(self, fg, None, None)
self.set_gain(self.subdev.gain_range()[1]) # set max Tx gain
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. Finally, we feed
any residual_freq to the s/w freq translator.
"""
r = self.u.tune(self.subdev._which, self.subdev, target_freq)
if r:
# Use residual_freq in s/w freq translator
return True
return False
def set_gain(self, gain):
self.gain = gain
self.subdev.set_gain(gain)
def set_enable(self, enable):
self.subdev.set_enable(enable) # set H/W Tx enable
if enable:
self.amp.set_k (self.normal_gain)
else:
self.amp.set_k (0)
#t = test_tone()
#t.start()
#t.wait()
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