Michael-
I'm trying to "calibrate" the flow-graph of the am_rcv_plasma_mod.py so
that the values displayed in the final window represent actual input
amplitudes.
The first step to do this would be to account for the internal gain; so I
need to divide through by a factor of 10^(gain) where gain is in db. To
implement this I define:
self.gain_correction = gr.divide_ff(math.log10(self.gain))
and later I implement it as follows:
self.connect (self.magblock, self.gain_correction)
and
if plot3:
self.scope = scopesink.scope_sink_f(self, self.panel,
title="AM Demodulated Time Series", sample_rate=demod_rate, size=(50,100),
t_scale=1.0e-3, v_scale=None, vbox=vbox)
self.connect(self.gain_correction, self.scope)
but I get the error:
File "am_rcv_plasma_mod.py", line 95, in __init__
self.gain_correction = gr.divide_ff(math.log10(self.gain))
AttributeError: 'am_plasma_rx_graph' object has no attribute 'gain'
How do I "grab" whatever the current value of the gain is and use it to
divide through? The gain will be set by either the mouse or the powermate
device.
Any thoughts?
thanks,
eric
************************************
Eric H. Matlis, Ph.D.
Aerospace & Mechanical Engineering Dept.
120 Hessert Center for Aerospace Research
University of Notre Dame
Notre Dame, IN 46556-5684
Phone: (574) 631-6054
Fax: (574) 631-8355
On Fri, 16 Mar 2007, Michael Dickens wrote:
On Mar 16, 2007, at 12:01 PM, [EMAIL PROTECTED] wrote:
1) do you happen to know where the default values for the control buttons
are set? I'd like to change the time scale from 100us/div to 1ms/div and
to set the Autorange to "on" by default.
In your "am_..." file, change the "scope_sink_f" call to inside "_build_gui",
"if plot3:":
self.scope = scopesink.scope_sink_f(self, self.panel, title="AM
Demodulated Time Series", sample_rate=demod_rate, size=(50,100),
t_scale=1.0e-3, v_scale=None)
the last 2 items set the time scale and autorange as you want.
2) do you know how to convert the integer values on the third window
(time-series) to actual voltage values as measured by the adc? It must be
a function of the internal gain and offset. I need to know these
eventually; this application is supposed to measure physical voltages, not
just produce sounds.
Not sure of this. Maybe whoever wrote the script knows? - MLD
#!/usr/bin/env python
#import scopesink_mod as scopesink
from gnuradio import gr, gru, eng_notation, optfir
from gnuradio import audio
from gnuradio import usrp
from gnuradio import blks
from gnuradio.eng_option import eng_option
from gnuradio.wxgui import slider, powermate
from gnuradio.wxgui import stdgui, form, fftsink
from optparse import OptionParser
import usrp_dbid
import sys
import math
import wx
import wx.lib.evtmgr as em
import scopesink_mod as scopesink
def pick_subdevice(u):
"""
The user didn't specify a subdevice on the command line.
Try for one of these, in order: TV_RX, BASIC_RX, whatever is on side A.
@return a subdev_spec
"""
return usrp.pick_subdev(u, (usrp_dbid.TV_RX,
usrp_dbid.TV_RX_REV_2,
usrp_dbid.BASIC_RX))
plot1 = 1
plot2 = 1
plot3 = 1
class am_plasma_rx_graph (stdgui.gui_flow_graph):
def __init__(self,frame,panel,vbox,argv):
stdgui.gui_flow_graph.__init__ (self,frame,panel,vbox,argv)
parser=OptionParser(option_class=eng_option)
parser.add_option("-R", "--rx-subdev-spec", type="subdev", default=None,
help="select USRP Rx side A or B (default=A)")
parser.add_option("-f", "--freq", type="eng_float", default=3e6,
help="set frequency to FREQ", metavar="FREQ")
parser.add_option("-g", "--gain", type="int", default=10,
help="set gain in dB (default is midpoint)")
parser.add_option("-O", "--audio-output", type="string", default="",
help="pcm device name. E.g., hw:0,0 or surround51 or
/dev/dsp")
(options, args) = parser.parse_args()
if len(args) != 0:
parser.print_help()
sys.exit(1)
self.frame = frame
self.panel = panel
self.vol = 0
self.state = "FREQ"
self.freq = 0
# build graph
self.u = usrp.source_c() # usrp is data source
adc_rate = self.u.adc_rate() # 64 MS/s
usrp_decim = 250
self.u.set_decim_rate(usrp_decim)
usrp_rate = adc_rate / usrp_decim # 256 kS/s
chanfilt_decim = 16
#chanfilt_decim = 512
demod_rate = usrp_rate / chanfilt_decim # 16 kHz
audio_decimation = 1
audio_rate = demod_rate / audio_decimation # 16 kHz
if options.rx_subdev_spec is None:
options.rx_subdev_spec = pick_subdevice(self.u)
# Select USRP channel (0)
self.u.set_mux(usrp.determine_rx_mux_value(self.u,
options.rx_subdev_spec))
# Tune to the desired IF frequency
self.subdev = usrp.selected_subdev(self.u, options.rx_subdev_spec)
# Channelize the signal of interest.
chan_filt_coeffs = gr.firdes.low_pass (1, # gain
usrp_rate, # sampling rate
#1000,
6000, # passband cutoff
500, # stopband cutoff
gr.firdes.WIN_HANN)
self.lpfilter = gr.fir_filter_ccf (chanfilt_decim,chan_filt_coeffs)
# Demodulate with classic sqrt (I*I + Q*Q)
self.magblock = gr.complex_to_mag()
self.volume_control = gr.multiply_const_ff(self.vol)
self.gain_correction = gr.divide_ff(math.log10(self.gain))
# Deemphasis. Is this necessary on AM?
#TAU = 75e-6 # 75us in US, 50us in EUR
#fftaps = [ 1 - math.exp(-1/TAU/usrp_rate), 0]
#fbtaps= [ 0 , math.exp(-1/TAU/usrp_rate) ]
#self.deemph = gr.iir_filter_ffd(fftaps,fbtaps)
# sound card as final sink
audio_sink = audio.sink (int (audio_rate),
options.audio_output,
False) # ok_to_block
# now wire it all together
self.connect (self.u, self.lpfilter)
self.connect (self.lpfilter, self.magblock)
self.connect (self.magblock, self.gain_correction)
self.connect (self.gain_correction, self.volume_control)
self.connect (self.volume_control, (audio_sink, 0))
#self.connect (self.volume_control, audio_filter)
#self.connect (audio_filter, (audio_sink, 0))
#self.connect (self.volume_control,self.deemph)
#self.connect (self.deemph,audio_filter)
#self.connect (audio_filter, (audio_sink, 0))
self._build_gui(vbox, usrp_rate, demod_rate, audio_rate)
if options.gain is None:
# if no gain was specified, use the mid-point in dB
g = self.subdev.gain_range()
options.gain = float(g[0]+g[1])/2
if abs(options.freq) < 1e6:
options.freq *= 1e6
# set initial values
self.set_gain(options.gain)
if not(self.set_freq(options.freq)):
self._set_status_msg("Failed to set initial frequency")
def _set_status_msg(self, msg, which=0):
self.frame.GetStatusBar().SetStatusText(msg, which)
def _build_gui(self, vbox, usrp_rate, demod_rate, audio_rate):
def _form_set_freq(kv):
return self.set_freq(kv['freq'])
if plot1:
self.src_fft = fftsink.fft_sink_c (self, self.panel, title="Raw
Spectrum From Sensor",
fft_size=1024,
sample_rate=usrp_rate, size=(50,200))
self.connect (self.u, self.src_fft)
vbox.Add (self.src_fft.win, 1, wx.EXPAND)
if plot2:
self.post_filt = fftsink.fft_sink_f (self, self.panel, title="AM
Demodulated Spectrum", fft_size=1024, sample_rate=demod_rate, size=(50,100))
self.connect (self.magblock,self.post_filt)
vbox.Add (self.post_filt.win, 1, wx.EXPAND)
if plot3:
self.scope = scopesink.scope_sink_f(self, self.panel, title="AM
Demodulated Time Series", sample_rate=demod_rate, size=(50,100),
t_scale=1.0e-3, v_scale=None, vbox=vbox)
self.connect(self.gain_correction, self.scope)
vbox.Add (self.scope.win, 1, wx.EXPAND)
# control area form at bottom
self.myform = myform = form.form()
hbox = wx.BoxSizer(wx.HORIZONTAL)
hbox.Add((5,0), 0)
myform['freq'] = form.float_field(
parent=self.panel, sizer=hbox, label="Carrier Freq", weight=1,
callback=myform.check_input_and_call(_form_set_freq,
self._set_status_msg))
hbox.Add((5,0), 0)
myform['freq_slider'] = \
form.quantized_slider_field(parent=self.panel, sizer=hbox, weight=3,
range=(.5e6, 3.5e6, 0.001e6),
callback=self.set_freq)
hbox.Add((5,0), 0)
vbox.Add(hbox, 0, wx.EXPAND)
hbox = wx.BoxSizer(wx.HORIZONTAL)
hbox.Add((5,0), 0)
myform['gain'] = \
form.quantized_slider_field(parent=self.panel, sizer=hbox,
label="Gain",
weight=3,
range=self.subdev.gain_range(),
callback=self.set_gain)
hbox.Add((5,0), 0)
vbox.Add(hbox, 0, wx.EXPAND)
try:
self.knob = powermate.powermate(self.frame)
self.rot = 0
powermate.EVT_POWERMATE_ROTATE (self.frame, self.on_rotate)
powermate.EVT_POWERMATE_BUTTON (self.frame, self.on_button)
except:
print "FYI: No Powermate or Contour Knob found"
def on_rotate (self, event):
self.rot += event.delta
if (self.state == "FREQ"):
if self.rot >= 3:
self.set_freq(self.freq + .001e6)
self.rot -= 3
elif self.rot <=-3:
self.set_freq(self.freq - .001e6)
self.rot += 3
else:
step = self.subdev.gain_range()[2]
if self.rot >= 3:
self.set_gain(self.gain + step)
self.rot -= 3
elif self.rot <=-3:
self.set_gain(self.gain - step)
self.rot += 3
self.update_status_bar ()
def on_button (self, event):
if event.value == 0: # button up
return
self.rot = 0
if self.state == "FREQ":
self.state = "GAIN"
else:
self.state = "FREQ"
self.update_status_bar ()
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 down converter.
"""
r = usrp.tune(self.u, 0, self.subdev, target_freq)
if r:
self.freq = target_freq
self.myform['freq'].set_value(target_freq) # update
displayed value
self.myform['freq_slider'].set_value(target_freq) # update
displayed value
self.update_status_bar()
self._set_status_msg("OK", 0)
return True
self._set_status_msg("Failed", 0)
return False
def set_gain(self, gain):
self.gain=gain
self.myform['gain'].set_value(gain) # update displayed value
self.subdev.set_gain(gain)
self.update_status_bar ()
def update_status_bar (self):
msg = "Gain:%r Setting:%s" % (self.gain, self.state)
self._set_status_msg(msg, 1)
if plot1:
self.src_fft.set_baseband_freq(self.freq)
def gain_range(self):
return (0, 20, 1)
if __name__ == '__main__':
app = stdgui.stdapp (am_plasma_rx_graph, "USRP PLASMA AM RX")
app.MainLoop ()
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