Hi! I need help to modify the usrp_fft.py file to show the spectrum of a input range (for example from 2.3GHz to 2.9GHz)

on 2008-10-14 16:30

on 2008-10-14 17:03

santi, such a wide frequency range is not possible due to limitations in the bandwidth between the usrp and the host currently you give usrp_fft a center frequency and a decimation rate, and from that it calculates the start and end frequencies... Dimitris Symeonidis "If you think you're too small to make a difference, try sleeping with a mosquito!" - Amnesty International

on 2008-10-14 17:08

Yes, but I think we can take the spectrum of every 8MHz band and put it into the computer so it can memorize and show it. Sorry for my english... 2008/10/14 Dimitris Symeonidis <azimout@gmail.com>

on 2008-10-14 17:50

Hi, > Santi Ortega <santiortega2000@gmail.com> wrote: > > Yes, but I think we can take the spectrum of every 8MHz band and put it into the > computer so it can memorize and show it. See usrp_spectrum_sense.py, it implements this technique to scan the entire spectrum available to each USRP daughter board. Regards, Firas

on 2008-10-14 17:53

ok, but this program doesn't show you anything... just uOuOuO... 2008/10/14 Firas Abbas <firasmail2000@yahoo.com>

on 2008-10-14 17:55

On Tue, Oct 14, 2008 at 11:33 AM, Santi Ortega <santiortega2000@gmail.com> wrote: > ok, but this program doesn't show you anything... just uOuOuO... Please reference: http://gnuradio.org/trac/wiki/UsrpFAQ/Gen#OUuainoutput Brian

on 2008-10-14 17:57

ok, so I have to modify this program to show in a Frame the results I want, haven't I? 2008/10/14 Brian Padalino <bpadalino@gmail.com>

on 2008-10-14 18:29

Hi, > Santi Ortega wrote : > > ok, so I have to modify this program to show in a Frame the results I > want, haven't I? Yes, OR, you can wait for me to write a detailed explanation (may be in two weeks) about "usrp_spectrum_sense.py". I think the understanding of this program is very important to every gnuradio user (practical FFT implementation + FSM control in its cpp code and weird Python commands in its .py!!!!) Best regards, Firas -- View this message in context: http://www.nabble.com/Wideband-Spectrum-Analyzer-t... Sent from the GnuRadio mailing list archive at Nabble.com.

on 2008-11-05 16:23

Hi everybody! I have modified usrp_spectrum_sense.py to plot the results with gnuplot. There are two files: widespectrum.py and plot.p I would like everybody to test it and report me the errors and how can I improve it. I've used USRPv1 + Flex2400. Thanks in advance! Here it goes... WIDESPECTRUM.PY: #!/usr/bin/env python # # Copyright 2005,2007 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, eng_notation, optfir, window from gnuradio import audio from gnuradio import usrp from gnuradio.eng_option import eng_option from optparse import OptionParser from usrpm import usrp_dbid import sys import math import struct import Gnuplot, Gnuplot.funcutils # Added to view the results 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, msg): self.center_freq = msg.arg1() self.vlen = int(msg.arg2()) assert(msg.length() == self.vlen * gr.sizeof_float) # FIXME consider using Numarray or NumPy vector t = msg.to_string() self.raw_data = t self.data = struct.unpack('%df' % (self.vlen,), t) class my_top_block(gr.top_block): def __init__(self): gr.top_block.__init__(self) usage = "usage: %prog [options] min_freq max_freq" # Example: ./widespectrum.py 2.23G 2.93G # that is the maximun range of the USRP Flex2400 device. parser = OptionParser(option_class=eng_option, usage=usage) parser.add_option("-R", "--rx-subdev-spec", type="subdev", default=(0,0), help="select USRP Rx side A or B (default=A)") parser.add_option("-g", "--gain", type="eng_float", default=None, help="set gain in dB (default is midpoint)") parser.add_option("", "--tune-delay", type="eng_float", default=1e-3, metavar="SECS", help="time to delay (in seconds) after changing frequency [default=%default]") parser.add_option("", "--dwell-delay", type="eng_float", default=10e-3, 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=64, help="set decimation to DECIM [default=%default]") parser.add_option("", "--real-time", action="store_true", default=False, help="Attempt to enable real-time scheduling") parser.add_option("-B", "--fusb-block-size", type="int", default=0, help="specify fast usb block size [default=%default]") parser.add_option("-N", "--fusb-nblocks", type="int", default=0, help="specify number of fast usb blocks [default=%default]") (options, args) = parser.parse_args() if len(args) != 2: parser.print_help() sys.exit(1) self.min_freq = eng_notation.str_to_num(args[0]) self.max_freq = eng_notation.str_to_num(args[1]) if self.min_freq > self.max_freq: self.min_freq, self.max_freq = self.max_freq, self.min_freq # swap them # FIXME We set MANUALLY the physical limits of the device. In this case the USRP Flex2400 limits. if self.min_freq < 2222000000: print ("The minimum frequency of this device is 2.222GHz") self.min_freq = 2222000000 if self.max_freq < 2222000000: print ("The minimum frequency of this device is 2.222GHz") self.max_freq = 2222000000 if self.min_freq > 2937000000: print ("The maximun frequency of this device is 2.937GHz") self.min_freq = 2937000000 if self.max_freq > 2937000000: print ("The maximun frequency of this device is 2.937GHz") self.max_freq = 2937000000 if self.min_freq == self.max_freq: print ("Do not use this program for a single frecuency analysis please") exit() 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" # If the user hasn't set the fusb_* parameters on the command line, # pick some values that will reduce latency. if 1: 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 # build graph self.u = usrp.source_c(fusb_block_size=options.fusb_block_size, fusb_nblocks=options.fusb_nblocks) adc_rate = self.u.adc_rate() # 64 MS/s usrp_decim = options.decim self.u.set_decim_rate(usrp_decim) usrp_rate = adc_rate / usrp_decim self.u.set_mux(usrp.determine_rx_mux_value(self.u, options.rx_subdev_spec)) self.subdev = usrp.selected_subdev(self.u, options.rx_subdev_spec) print "Using RX d'board %s" % (self.subdev.side_and_name(),) s2v = gr.stream_to_vector(gr.sizeof_gr_complex, self.fft_size) mywindow = window.blackmanharris(self.fft_size) fft = gr.fft_vcc(self.fft_size, True, mywindow) power = 0 for tap in mywindow: power += tap*tap 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 75% of the actual data throughput. # This allows us to discard the bins on both ends of the spectrum. self.freq_step = 0.75 * usrp_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 # We define the minimum, maximum and frequency step in a global statement to use them later. global min_center_freq, max_center_freq, freq_step min_center_freq = self.min_center_freq max_center_freq = self.max_center_freq freq_step = self.freq_step tune_delay = max(0, int(round(options.tune_delay * usrp_rate / self.fft_size))) # in fft_frames dwell_delay = max(1, int(round(options.dwell_delay * usrp_rate / self.fft_size))) # in fft_frames self.msgq = gr.msg_queue(16) self._tune_callback = tune(self) # hang on to this to keep it from being GC'd stats = gr.bin_statistics_f(self.fft_size, self.msgq, self._tune_callback, tune_delay, dwell_delay) # FIXME leave out the log10 until we speed it up self.connect(self.u, s2v, fft, c2mag, log, stats) #self.connect(self.u, s2v, fft, c2mag, stats) 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 self.set_gain(options.gain) print "gain =", options.gain def set_next_freq(self): 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 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. """ return self.u.tune(0, self.subdev, target_freq) def set_gain(self, gain): self.subdev.set_gain(gain) def mean(data): # Returns the arithmetic mean of a numeric list return sum(data) / len(data) def main_loop(tb): # We give basic information about the Spectrum Analysis print "The start frequency is %s Hz" % min_center_freq print "The final frequency is %s Hz" % max_center_freq print "The frequency step is %s Hz" % freq_step g = Gnuplot.Gnuplot(debug=1) 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 m = parse_msg(tb.msgq.delete_head()) # Print center freq so we know that something is happening... #print (m.center_freq) # FIXME do something useful with the data... # Mechanism to save in a file (power.dat) 2 columns, one for the frequencies and the other for the mean of the FFT_SIZE points of m.data if m.center_freq == min_center_freq: # If we get the minimum frequency, it'll reset the power.dat file power=open("power.dat", "w") # It will overwrite the power.dat file power=open("power.dat", "a") # Each loop, it adds a dataline (append) p=str(m.center_freq) # with a frequency and the mean of the 256 FFT samples (Power in dB) media=str(mean(m.data)) # todo= p + " " + media + '\n' # power.write(todo) # if m.center_freq == (max_center_freq-freq_step): # If it gets the final frecuency p=str(m.center_freq) # It'll write the last frecuency with its Power in the power.dat file media=str(mean(m.data)) # todo= p + " " + media + '\n' # power.write(todo) # g.load("plot.p") # Load the plot with the data obtained from URSP power=open("power.dat", "a") # Without this line, the file will start with the last frecuency #g.hardcopy('spectrum.ps', enhanced=1, color=1) # It does a plot copy to the hard disk (I think there's not enough time to do it) # m.data in 'w' mode: only write, if it exist a file with the same name, it'll be overwrite. # 'a' to append # 'r+' for read and write # m.data are the mag_squared of the fft output (they are in the # standard order. I.e., bin 0 == DC.) # You'll probably want to do the equivalent of "fftshift" on them # m.raw_data is a string that contains the binary floats. # You could write this as binary to a file. if __name__ == '__main__': tb = my_top_block() try: tb.start() # start executing flow graph in another thread... main_loop(tb) except KeyboardInterrupt: pass PLOT.P set autoscale unset logscale unset label set xtic auto set ytic auto set title "Wideband Spectrum Analyzer" set xlabel "Frecuency" set ylabel "Power (dB)" set grid plot "power.dat" using 1:2 title 'Mean power' with linespoints -- View this message in context: http://www.nabble.com/Wideband-Spectrum-Analyzer-t... Sent from the GnuRadio mailing list archive at Nabble.com.

on 2009-06-23 11:24

Firas, have to written a detailed explanation about "usrp_spectrum_sense.py" ? I am unable to find it. Please let us know the link for the same... Shesh Firas A. wrote: > > -- View this message in context: http://www.nabble.com/Wideband-Spectrum-Analyzer-t... Sent from the GnuRadio mailing list archive at Nabble.com.

on 2009-06-23 13:36

shesh wrote: > > Firas, > have to written a detailed explanation about "usrp_spectrum_sense.py" ? I > am unable to find it. Please let us know the link for the same... > > Shesh > > http://www.nabble.com/Some-usrp_spectrum_sense.py-... -- View this message in context: http://www.nabble.com/Wideband-Spectrum-Analyzer-t... Sent from the GnuRadio mailing list archive at Nabble.com.

on 2010-01-13 00:58

Hello I wonder someone can help me out. While testing this code, the media with the different size of fft shows different value. I would like to know how I can get the same media value regardless of using different fft size. Thanks, Kyungtae-- Santix wrote : media=str(mean(m.data)) # todo= p + " " + media + '\n' # power.write(todo) # -- This message was sent on behalf of kyungtae@nec-labs.com at openSubscriber.com http://www.opensubscriber.com/message/discuss-gnur...

on 2010-01-13 01:05

See how the logpwrfft in gnuradio adjusts for different windows and fft lengths: http://gnuradio.org/redmine/repositories/entry/gnu... -Josh