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#!/usr/bin/env python
#
# Copyright 2008 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, eng_notation, optfir, window
from gnuradio import msdd
from gnuradio.eng_option import eng_option
from optparse import OptionParser
import sys
import math
import struct
from pylab import *
from numpy import array
import time
matplotlib.interactive(True)
matplotlib.use('TkAgg')
class tune(gr.feval_dd):
"""
This class allows C++ code to callback into python.
"""
def __init__(self, tb):
gr.feval_dd.__init__(self)
self.tb = tb
def eval(self, ignore):
"""
This method is called from gr.bin_statistics_f when it wants to change
the center frequency. This method tunes the front end to the new center
frequency, and returns the new frequency as its result.
"""
try:
# We use this try block so that if something goes wrong from here
# down, at least we'll have a prayer of knowing what went wrong.
# Without this, you get a very mysterious:
#
# terminate called after throwing an instance of 'Swig::DirectorMethodException'
# Aborted
#
# message on stderr. Not exactly helpful ;)
new_freq = self.tb.set_next_freq()
return new_freq
except Exception, e:
print "tune: Exception: ", e
class parse_msg(object):
def __init__(self, sample_rate, percent):
self.axis_font_size = 16
self.label_font_size = 18
self.title_font_size = 20
self.text_size = 22
# Set up figures and subplots
self.fig = figure(1, facecolor="w", figsize=(12,9))
self.sp = self.fig.add_subplot(1,1,1)
self.pl = self.sp.matshow(100*[range(100),])
params = {'xtick.labelsize': self.axis_font_size,
'ytick.labelsize': self.axis_font_size}
rcParams.update(params)
# Throw up some title info
self.sp.set_title(("FFT"), fontsize=self.title_font_size, fontweight="bold")
self.sp.set_xlabel("Frequency (Hz)", fontsize=self.label_font_size, fontweight="bold")
self.sp.set_ylabel("Sample index (should be time)", fontsize=self.label_font_size, fontweight="bold")
self.freqrange = list()
self.data = list()
self.data3 = list()
self.index = 0
self.last_cfreq = 0
# So we know how to splice the data
self.sample_rate = sample_rate
self.percent = (1.0-percent)/2.0
def parse(self, msg):
self.center_freq = msg.arg1() # read the current center frequency
self.vlen = int(msg.arg2()) # read the length of the data set received
# wait until we wrap around before plotting the entire collected band
if(self.center_freq < self.last_cfreq):
#print "Plotting spectrum\n"
# If we have 100 sets, start dropping the oldest
if(len(self.data3) > 100):
self.data3.pop(0)
self.data3.append(self.data)
# add the new data to the plot
self.pl.set_data(self.data3)
draw()
# reset lists to collect next round
self.index = 0
del self.freqrange
self.freqrange = list()
del self.data
self.data = list()
#raw_input()
self.last_cfreq = self.center_freq
startind = int(self.percent * self.vlen)
endind = int((1.0 - self.percent) * self.vlen)
fstep = self.sample_rate / self.vlen
f = [self.center_freq - self.sample_rate/2.0 + i*fstep for i in range(startind, endind)]
self.freqrange += f
t = msg.to_string();
d = struct.unpack('%df' % (self.vlen,), t)
self.data += [di for di in d[startind:endind]]
class my_top_block(gr.top_block):
def __init__(self):
gr.top_block.__init__(self)
# Build an options parser to bring in information from the user on usage
usage = "usage: %prog [options] host min_freq max_freq"
parser = OptionParser(option_class=eng_option, usage=usage)
parser.add_option("-g", "--gain", type="eng_float", default=32,
help="set gain in dB (default is midpoint)")
parser.add_option("", "--tune-delay", type="eng_float", default=5e-5, metavar="SECS",
help="time to delay (in seconds) after changing frequency [default=%default]")
parser.add_option("", "--dwell-delay", type="eng_float", default=50e-5, metavar="SECS",
help="time to dwell (in seconds) at a given frequncy [default=%default]")
parser.add_option("-F", "--fft-size", type="int", default=256,
help="specify number of FFT bins [default=%default]")
parser.add_option("-d", "--decim", type="intx", default=16,
help="set decimation to DECIM [default=%default]")
parser.add_option("", "--real-time", action="store_true", default=False,
help="Attempt to enable real-time scheduling")
(options, args) = parser.parse_args()
if len(args) != 3:
parser.print_help()
sys.exit(1)
# get user-provided info on address of MSDD and frequency to sweep
self.address = args[0]
self.min_freq = eng_notation.str_to_num(args[1])
self.max_freq = eng_notation.str_to_num(args[2])
self.decim = options.decim
self.gain = options.gain
if self.min_freq > self.max_freq:
self.min_freq, self.max_freq = self.max_freq, self.min_freq # swap them
self.fft_size = options.fft_size
if not options.real_time:
realtime = False
else:
# 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"
# Sampling rate is hardcoded and cannot be read off device
adc_rate = 102.4e6
self.int_rate = adc_rate / self.decim
print "Sampling rate: ", self.int_rate
# build graph
self.port = 10001 # required port for UDP packets
# which board, op mode, adx, port
# self.src = msdd.source_c(0, 1, self.address, self.port) # build source object
self.conv = gr.interleaved_short_to_complex();
self.src = msdd.source_simple(self.address,self.port);
self.src.set_decim_rate(self.decim) # set decimation rate
# self.src.set_desired_packet_size(0, 1460) # set packet size to collect
self.set_gain(self.gain) # set receiver's attenuation
self.set_freq(self.min_freq) # set receiver's rx frequency
# restructure into vector format for FFT input
s2v = gr.stream_to_vector(gr.sizeof_gr_complex, self.fft_size)
# set up FFT processing block
mywindow = window.blackmanharris(self.fft_size)
fft = gr.fft_vcc(self.fft_size, True, mywindow, True)
power = 0
for tap in mywindow:
power += tap*tap
# calculate magnitude squared of output of FFT
c2mag = gr.complex_to_mag_squared(self.fft_size)
# FIXME the log10 primitive is dog slow
log = gr.nlog10_ff(10, self.fft_size,
-20*math.log10(self.fft_size)-10*math.log10(power/self.fft_size))
# Set the freq_step to % of the actual data throughput.
# This allows us to discard the bins on both ends of the spectrum.
self.percent = 0.4
# Calculate the frequency steps to use in the collection over the whole bandwidth
self.freq_step = self.percent * self.int_rate
self.min_center_freq = self.min_freq + self.freq_step/2
nsteps = math.ceil((self.max_freq - self.min_freq) / self.freq_step)
self.max_center_freq = self.min_center_freq + (nsteps * self.freq_step)
self.next_freq = self.min_center_freq
# use these values to set receiver settling time between samples and sampling time
# the default values provided seem to work well with the MSDD over 100 Mbps ethernet
tune_delay = max(0, int(round(options.tune_delay * self.int_rate / self.fft_size))) # in fft_frames
dwell_delay = max(1, int(round(options.dwell_delay * self.int_rate / self.fft_size))) # in fft_frames
# set up message callback routine to get data from bin_statistics_f block
self.msgq = gr.msg_queue(16)
self._tune_callback = tune(self) # hang on to this to keep it from being GC'd
# FIXME this block doesn't like to work with negatives because of the "d_max[i]=0" on line
# 151 of gr_bin_statistics_f.cc file. Set this to -10000 or something to get it to work.
stats = gr.bin_statistics_f(self.fft_size, self.msgq,
self._tune_callback, tune_delay, dwell_delay)
# FIXME there's a concern over the speed of the log calculation
# We can probably calculate the log inside the stats block
self.connect(self.src, self.conv, s2v, fft, c2mag, log, stats)
def set_next_freq(self):
''' Find and set the next frequency of the reciver. After going past the maximum frequency,
the frequency is wrapped around to the start again'''
target_freq = self.next_freq
self.next_freq = self.next_freq + self.freq_step
if self.next_freq >= self.max_center_freq:
self.next_freq = self.min_center_freq
if not self.set_freq(target_freq):
print "Failed to set frequency to", target_freq
return target_freq
def set_freq(self, target_freq):
"""
Set the center frequency we're interested in.
@param target_freq: frequency in Hz
@rypte: bool
"""
return self.src.set_rx_freq(0, target_freq)
def set_gain(self, gain):
self.src.set_pga(0, gain)
def main_loop(tb):
# Set up parser to get data from stats block and display them.
msgparser = parse_msg(tb.int_rate, tb.percent)
while 1:
# Get the next message sent from the C++ code (blocking call).
# It contains the center frequency and the mag squared of the fft
d = tb.msgq.delete_head();
print d.to_string();
msgparser.parse(d)
#print msgparser.center_freq
if __name__ == '__main__':
tb = my_top_block()
try:
tb.start() # start executing flow graph in another thread...
main_loop(tb)
except KeyboardInterrupt:
pass
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