3 # Copyright 2004,2005,2007 Free Software Foundation, Inc.
5 # This file is part of GNU Radio
7 # GNU Radio is free software; you can redistribute it and/or modify
8 # it under the terms of the GNU General Public License as published by
9 # the Free Software Foundation; either version 3, or (at your option)
12 # GNU Radio is distributed in the hope that it will be useful,
13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 # GNU General Public License for more details.
17 # You should have received a copy of the GNU General Public License
18 # along with GNU Radio; see the file COPYING. If not, write to
19 # the Free Software Foundation, Inc., 51 Franklin Street,
20 # Boston, MA 02110-1301, USA.
26 # Pulsar receiver application
28 # Performs both harmonic folding analysis
29 # and epoch folding analysis
32 from gnuradio import gr, gru, blks2, audio
33 from usrpm import usrp_dbid
34 from gnuradio import usrp, optfir
35 from gnuradio import eng_notation
36 from gnuradio.eng_option import eng_option
37 from gnuradio.wxgui import stdgui, ra_fftsink, ra_stripchartsink, form, slider
38 from optparse import OptionParser
49 class app_flow_graph(stdgui2.std_top_block):
50 def __init__(self, frame, panel, vbox, argv):
51 stdgui2.std_top_block.__init__(self)
56 parser = OptionParser(option_class=eng_option)
57 parser.add_option("-R", "--rx-subdev-spec", type="subdev", default=(0, 0),
58 help="select USRP Rx side A or B (default=A)")
59 parser.add_option("-d", "--decim", type="int", default=16,
60 help="set fgpa decimation rate to DECIM [default=%default]")
61 parser.add_option("-f", "--freq", type="eng_float", default=None,
62 help="set frequency to FREQ", metavar="FREQ")
63 parser.add_option("-Q", "--observing", type="eng_float", default=0.0,
64 help="set observing frequency to FREQ")
65 parser.add_option("-a", "--avg", type="eng_float", default=1.0,
66 help="set spectral averaging alpha")
67 parser.add_option("-V", "--favg", type="eng_float", default=2.0,
68 help="set folder averaging alpha")
69 parser.add_option("-g", "--gain", type="eng_float", default=None,
70 help="set gain in dB (default is midpoint)")
71 parser.add_option("-l", "--reflevel", type="eng_float", default=30.0,
72 help="Set pulse display reference level")
73 parser.add_option("-L", "--lowest", type="eng_float", default=1.5,
74 help="Lowest valid frequency bin")
75 parser.add_option("-e", "--longitude", type="eng_float", default=-76.02, help="Set Observer Longitude")
76 parser.add_option("-c", "--latitude", type="eng_float", default=44.85, help="Set Observer Latitude")
77 parser.add_option("-F", "--fft_size", type="eng_float", default=1024, help="Size of FFT")
79 parser.add_option ("-t", "--threshold", type="eng_float", default=2.5, help="pulsar threshold")
80 parser.add_option("-p", "--lowpass", type="eng_float", default=100, help="Pulse spectra cutoff freq")
81 parser.add_option("-P", "--prefix", default="./", help="File prefix")
82 parser.add_option("-u", "--pulsefreq", type="eng_float", default=0.748, help="Observation pulse rate")
83 parser.add_option("-D", "--dm", type="eng_float", default=1.0e-5, help="Dispersion Measure")
84 parser.add_option("-O", "--doppler", type="eng_float", default=1.0, help="Doppler ratio")
85 parser.add_option("-B", "--divbase", type="eng_float", default=20, help="Y/Div menu base")
86 parser.add_option("-I", "--division", type="eng_float", default=100, help="Y/Div")
87 parser.add_option("-A", "--audio_source", default="plughw:0,0", help="Audio input device spec")
88 (options, args) = parser.parse_args()
93 self.show_debug_info = True
95 self.reflevel = options.reflevel
96 self.divbase = options.divbase
97 self.division = options.division
98 self.audiodev = options.audio_source
100 # Low-pass cutoff for post-detector filter
101 # Set to 100Hz usually, since lots of pulsars fit in this
103 self.lowpass = options.lowpass
105 # What is lowest valid frequency bin in post-detector FFT?
106 # There's some pollution very close to DC
107 self.lowest_freq = options.lowest
109 # What (dB) threshold to use in determining spectral candidates
110 self.threshold = options.threshold
112 # Filename prefix for recording file
113 self.prefix = options.prefix
115 # Dispersion Measure (DM)
118 # Doppler shift, as a ratio
119 # 1.0 == no doppler shift
120 # 1.005 == a little negative shift
121 # 0.995 == a little positive shift
122 self.doppler = options.doppler
125 # Input frequency and observing frequency--not necessarily the
126 # same thing, if we're looking at the IF of some downconverter
127 # that's ahead of the USRP and daughtercard. This distinction
128 # is important in computing the correct de-dispersion filter.
130 self.frequency = options.freq
131 if options.observing <= 0:
132 self.observing_freq = options.freq
134 self.observing_freq = options.observing
137 self.u = usrp.source_c(decim_rate=options.decim)
138 self.u.set_mux(usrp.determine_rx_mux_value(self.u, options.rx_subdev_spec))
141 # Recording file, in case we ever need to record baseband data
143 self.recording = gr.file_sink(gr.sizeof_char, "/dev/null")
144 self.recording_state = False
146 self.pulse_recording = gr.file_sink(gr.sizeof_short, "/dev/null")
147 self.pulse_recording_state = False
150 # We come up with recording turned off, but the user may
151 # request recording later on
152 self.recording.close()
153 self.pulse_recording.close()
156 # Need these two for converting 12-bit baseband signals to 8-bit
158 self.tofloat = gr.complex_to_float()
159 self.tochar = gr.float_to_char()
161 # Need this for recording pulses (post-detector)
162 self.toshort = gr.float_to_short()
166 # The spectral measurer sets this when it has a valid
167 # average spectral peak-to-peak distance
168 # We can then use this to program the parameters for the epoch folder
170 # We set a sentimental value here
171 self.pulse_freq = options.pulsefreq
173 # Folder runs at this raw sample rate
174 self.folder_input_rate = 20000
176 # Each pulse in the epoch folder is sampled at 128 times the nominal
182 # Try to find candidate parameters for rational resampler
186 for i in range(20,300):
187 input_rate = self.folder_input_rate
188 output_rate = int(self.pulse_freq * i)
189 interp = gru.lcm(input_rate, output_rate) / input_rate
190 decim = gru.lcm(input_rate, output_rate) / output_rate
191 if (interp < 500 and decim < 250000):
194 # We didn't find anything, bail!
195 if (len(candidates) < 1):
196 print "Couldn't converge on resampler parameters"
200 # Now try to find candidate with the least sampling error
204 diff = self.pulse_freq * i
205 diff = diff - int(diff)
211 input_rate = self.folder_input_rate
212 output_rate = int(self.pulse_freq * save_i)
214 # Compute new interp and decim, based on best candidate
215 interp = gru.lcm(input_rate, output_rate) / input_rate
216 decim = gru.lcm(input_rate, output_rate) / output_rate
218 # Save optimized folding parameters, used later
219 self.folding = save_i
220 self.interp = int(interp)
221 self.decim = int(decim)
223 # So that we can view 4 pulses in the pulse viewer window
226 # determine the daughterboard subdevice we're using
227 self.subdev = usrp.selected_subdev(self.u, options.rx_subdev_spec)
228 self.cardtype = self.u.daughterboard_id(0)
230 # Compute raw input rate
231 input_rate = self.u.adc_freq() / self.u.decim_rate()
233 # BW==input_rate for complex data
237 # Set baseband filter bandwidth if DBS_RX:
239 if self.cardtype == usrp_dbid.DBS_RX:
243 self.subdev.set_bw(lbw)
246 # We use this as a crude volume control for the audio output
248 self.volume = gr.multiply_const_ff(10**(-1))
252 # Create location data for ephem package
254 self.locality = ephem.Observer()
255 self.locality.long = str(options.longitude)
256 self.locality.lat = str(options.latitude)
259 # What is the post-detector LPF cutoff for the FFT?
261 PULSAR_MAX_FREQ=int(options.lowpass)
263 # First low-pass filters down to input_rate/FIRST_FACTOR
264 # and decimates appropriately
265 FIRST_FACTOR=int(input_rate/(self.folder_input_rate/2))
266 first_filter = gr.firdes.low_pass (1.0,
268 input_rate/FIRST_FACTOR,
269 input_rate/(FIRST_FACTOR*20),
270 gr.firdes.WIN_HAMMING)
272 # Second filter runs at the output rate of the first filter,
273 # And low-pass filters down to PULSAR_MAX_FREQ*10
275 second_input_rate = int(input_rate/(FIRST_FACTOR/2))
276 second_filter = gr.firdes.band_pass(1.0, second_input_rate,
280 gr.firdes.WIN_HAMMING)
282 # Third filter runs at PULSAR_MAX_FREQ*20
283 # and filters down to PULSAR_MAX_FREQ
285 third_input_rate = PULSAR_MAX_FREQ*20
286 third_filter = gr.firdes_band_pass(1.0, third_input_rate,
287 0.10, PULSAR_MAX_FREQ,
288 PULSAR_MAX_FREQ/10.0,
289 gr.firdes.WIN_HAMMING)
293 # Create the appropriate FFT scope
295 self.scope = ra_fftsink.ra_fft_sink_f (panel,
296 fft_size=int(options.fft_size), sample_rate=PULSAR_MAX_FREQ*2,
297 title="Post-detector spectrum",
298 ofunc=self.pulsarfunc, xydfunc=self.xydfunc, fft_rate=200)
301 # Tell scope we're looking from DC to PULSAR_MAX_FREQ
303 self.scope.set_baseband_freq (0.0)
307 # Setup stripchart for showing pulse profiles
309 hz = "%5.3fHz " % self.pulse_freq
310 per = "(%5.3f sec)" % (1.0/self.pulse_freq)
311 sr = "%d sps" % (int(self.pulse_freq*self.folding))
312 self.chart = ra_stripchartsink.stripchart_sink_f (panel,
314 stripsize=self.folding*FOLD_MULT, parallel=True, title="Pulse Profiles: "+hz+per,
315 xlabel="Seconds @ "+sr, ylabel="Level", autoscale=True,
316 divbase=self.divbase, scaling=1.0/(self.folding*self.pulse_freq))
317 self.chart.set_ref_level(self.reflevel)
318 self.chart.set_y_per_div(self.division)
320 # De-dispersion filter setup
322 # Do this here, just before creating the filter
323 # that will use the taps.
325 ntaps = self.compute_disp_ntaps(self.dm,self.bw,self.observing_freq)
327 # Taps for the de-dispersion filter
328 self.disp_taps = Numeric.zeros(ntaps,Numeric.Complex64)
330 # Compute the de-dispersion filter now
331 self.compute_dispfilter(self.dm,self.doppler,
332 self.bw,self.observing_freq)
335 # Call constructors for receive chains
339 # Now create the FFT filter using the computed taps
340 self.dispfilt = gr.fft_filter_ccc(1, self.disp_taps)
345 print "input_rate ", second_input_rate, "audiodev ", self.audiodev
346 self.audio = audio.sink(second_input_rate, self.audiodev)
349 # The three post-detector filters
350 # Done this way to allow an audio path (up to 10Khz)
351 # ...and also because going from xMhz down to ~100Hz
352 # In a single filter doesn't seem to work.
354 self.first = gr.fir_filter_fff (FIRST_FACTOR/2, first_filter)
356 p = second_input_rate / (PULSAR_MAX_FREQ*20)
357 self.second = gr.fir_filter_fff (int(p), second_filter)
358 self.third = gr.fir_filter_fff (10, third_filter)
361 self.detector = gr.complex_to_mag_squared()
363 self.enable_comb_filter = False
364 # Epoch folder comb filter
365 if self.enable_comb_filter == True:
366 bogtaps = Numeric.zeros(512, Numeric.Float64)
367 self.folder_comb = gr.fft_filter_ccc(1,bogtaps)
370 self.folder_rr = blks2.rational_resampler_fff(self.interp, self.decim)
372 # Epoch folder bandpass
373 bogtaps = Numeric.zeros(1, Numeric.Float64)
374 self.folder_bandpass = gr.fir_filter_fff (1, bogtaps)
376 # Epoch folder F2C/C2F
377 self.folder_f2c = gr.float_to_complex()
378 self.folder_c2f = gr.complex_to_float()
381 self.folder_s2p = gr.serial_to_parallel (gr.sizeof_float,
382 self.folding*FOLD_MULT)
384 # Epoch folder IIR Filter (produces average pulse profiles)
385 self.folder_iir = gr.single_pole_iir_filter_ff(1.0/options.favg,
386 self.folding*FOLD_MULT)
389 # Set all the epoch-folder goop up
391 self.set_folding_params()
394 # Start connecting configured modules in the receive chain
397 # Connect raw USRP to de-dispersion filter, detector
398 self.connect(self.u, self.dispfilt, self.detector)
400 # Connect detector output to FIR LPF
401 # in two stages, followed by the FFT scope
402 self.connect(self.detector, self.first,
403 self.second, self.third, self.scope)
405 # Connect audio output
406 self.connect(self.first, self.volume)
407 self.connect(self.volume, (self.audio, 0))
408 self.connect(self.volume, (self.audio, 1))
410 # Connect epoch folder
411 if self.enable_comb_filter == True:
412 self.connect (self.first, self.folder_bandpass, self.folder_rr,
414 self.folder_comb, self.folder_c2f,
415 self.folder_s2p, self.folder_iir,
419 self.connect (self.first, self.folder_bandpass, self.folder_rr,
420 self.folder_s2p, self.folder_iir, self.chart)
422 # Connect baseband recording file (initially /dev/null)
423 self.connect(self.u, self.tofloat, self.tochar, self.recording)
425 # Connect pulse recording file (initially /dev/null)
426 self.connect(self.first, self.toshort, self.pulse_recording)
429 # Build the GUI elements
431 self._build_gui(vbox)
433 # Make GUI agree with command-line
434 self.myform['average'].set_value(int(options.avg))
435 self.myform['foldavg'].set_value(int(options.favg))
438 # Make spectral averager agree with command line
439 if options.avg != 1.0:
440 self.scope.set_avg_alpha(float(1.0/options.avg))
441 self.scope.set_average(True)
446 if options.gain is None:
447 # if no gain was specified, use the mid-point in dB
448 g = self.subdev.gain_range()
449 options.gain = float(g[0]+g[1])/2
451 if options.freq is None:
452 # if no freq was specified, use the mid-point
453 r = self.subdev.freq_range()
454 options.freq = float(r[0]+r[1])/2
456 self.set_gain(options.gain)
457 self.set_volume(-10.0)
459 if not(self.set_freq(options.freq)):
460 self._set_status_msg("Failed to set initial frequency")
462 self.myform['decim'].set_value(self.u.decim_rate())
463 self.myform['fs@usb'].set_value(self.u.adc_freq() / self.u.decim_rate())
464 self.myform['dbname'].set_value(self.subdev.name())
465 self.myform['DM'].set_value(self.dm)
466 self.myform['Doppler'].set_value(self.doppler)
469 # Start the timer that shows current LMST on the GUI
471 self.lmst_timer.Start(1000)
474 def _set_status_msg(self, msg):
475 self.frame.GetStatusBar().SetStatusText(msg, 0)
477 def _build_gui(self, vbox):
479 def _form_set_freq(kv):
480 return self.set_freq(kv['freq'])
482 def _form_set_dm(kv):
483 return self.set_dm(kv['DM'])
485 def _form_set_doppler(kv):
486 return self.set_doppler(kv['Doppler'])
488 # Position the FFT or Waterfall
489 vbox.Add(self.scope.win, 5, wx.EXPAND)
490 vbox.Add(self.chart.win, 5, wx.EXPAND)
492 # add control area at the bottom
493 self.myform = myform = form.form()
494 hbox = wx.BoxSizer(wx.HORIZONTAL)
495 hbox.Add((7,0), 0, wx.EXPAND)
496 vbox1 = wx.BoxSizer(wx.VERTICAL)
497 myform['freq'] = form.float_field(
498 parent=self.panel, sizer=vbox1, label="Center freq", weight=1,
499 callback=myform.check_input_and_call(_form_set_freq, self._set_status_msg))
501 vbox1.Add((3,0), 0, 0)
503 # To show current Local Mean Sidereal Time
504 myform['lmst_high'] = form.static_text_field(
505 parent=self.panel, sizer=vbox1, label="Current LMST", weight=1)
506 vbox1.Add((3,0), 0, 0)
508 # To show current spectral cursor data
509 myform['spec_data'] = form.static_text_field(
510 parent=self.panel, sizer=vbox1, label="Pulse Freq", weight=1)
511 vbox1.Add((3,0), 0, 0)
513 # To show best pulses found in FFT output
514 myform['best_pulse'] = form.static_text_field(
515 parent=self.panel, sizer=vbox1, label="Best freq", weight=1)
516 vbox1.Add((3,0), 0, 0)
518 vboxBogus = wx.BoxSizer(wx.VERTICAL)
519 vboxBogus.Add ((2,0), 0, wx.EXPAND)
520 vbox2 = wx.BoxSizer(wx.VERTICAL)
521 g = self.subdev.gain_range()
522 myform['gain'] = form.slider_field(parent=self.panel, sizer=vbox2, label="RF Gain",
524 min=int(g[0]), max=int(g[1]),
525 callback=self.set_gain)
527 vbox2.Add((6,0), 0, 0)
528 myform['average'] = form.slider_field(parent=self.panel, sizer=vbox2,
529 label="Spectral Averaging", weight=1, min=1, max=200, callback=self.set_averaging)
530 vbox2.Add((6,0), 0, 0)
531 myform['foldavg'] = form.slider_field(parent=self.panel, sizer=vbox2,
532 label="Folder Averaging", weight=1, min=1, max=20, callback=self.set_folder_averaging)
533 vbox2.Add((6,0), 0, 0)
534 myform['volume'] = form.quantized_slider_field(parent=self.panel, sizer=vbox2,
535 label="Audio Volume", weight=1, range=(-20, 0, 0.5), callback=self.set_volume)
536 vbox2.Add((6,0), 0, 0)
537 myform['DM'] = form.float_field(
538 parent=self.panel, sizer=vbox2, label="DM", weight=1,
539 callback=myform.check_input_and_call(_form_set_dm))
540 vbox2.Add((6,0), 0, 0)
541 myform['Doppler'] = form.float_field(
542 parent=self.panel, sizer=vbox2, label="Doppler", weight=1,
543 callback=myform.check_input_and_call(_form_set_doppler))
544 vbox2.Add((6,0), 0, 0)
547 # Baseband recording control
548 buttonbox = wx.BoxSizer(wx.HORIZONTAL)
549 self.record_control = form.button_with_callback(self.panel,
550 label="Recording baseband: Off ",
551 callback=self.toggle_recording)
552 self.record_pulse_control = form.button_with_callback(self.panel,
553 label="Recording pulses: Off ",
554 callback=self.toggle_pulse_recording)
556 buttonbox.Add(self.record_control, 0, wx.CENTER)
557 buttonbox.Add(self.record_pulse_control, 0, wx.CENTER)
558 vbox.Add(buttonbox, 0, wx.CENTER)
559 hbox.Add(vbox1, 0, 0)
560 hbox.Add(vboxBogus, 0, 0)
561 hbox.Add(vbox2, wx.ALIGN_RIGHT, 0)
562 vbox.Add(hbox, 0, wx.EXPAND)
564 self._build_subpanel(vbox)
566 self.lmst_timer = wx.PyTimer(self.lmst_timeout)
570 def _build_subpanel(self, vbox_arg):
571 # build a secondary information panel (sometimes hidden)
573 # FIXME figure out how to have this be a subpanel that is always
574 # created, but has its visibility controlled by foo.Show(True/False)
576 if not(self.show_debug_info):
583 #panel = wx.Panel(self.panel, -1)
584 #vbox = wx.BoxSizer(wx.VERTICAL)
586 hbox = wx.BoxSizer(wx.HORIZONTAL)
588 myform['decim'] = form.static_float_field(
589 parent=panel, sizer=hbox, label="Decim")
592 myform['fs@usb'] = form.static_float_field(
593 parent=panel, sizer=hbox, label="Fs@USB")
596 myform['dbname'] = form.static_text_field(
597 parent=panel, sizer=hbox)
600 myform['baseband'] = form.static_float_field(
601 parent=panel, sizer=hbox, label="Analog BB")
604 myform['ddc'] = form.static_float_field(
605 parent=panel, sizer=hbox, label="DDC")
608 vbox.Add(hbox, 0, wx.EXPAND)
612 def set_freq(self, target_freq):
614 Set the center frequency we're interested in.
616 @param target_freq: frequency in Hz
619 Tuning is a two step process. First we ask the front-end to
620 tune as close to the desired frequency as it can. Then we use
621 the result of that operation and our target_frequency to
622 determine the value for the digital down converter.
624 r = usrp.tune(self.u, 0, self.subdev, target_freq)
627 self.myform['freq'].set_value(target_freq) # update displayed value
628 self.myform['baseband'].set_value(r.baseband_freq)
629 self.myform['ddc'].set_value(r.dxc_freq)
630 # Adjust self.frequency, and self.observing_freq
631 # We pick up the difference between the current self.frequency
632 # and the just-programmed one, and use this to adjust
633 # self.observing_freq. We have to do it this way to
634 # make the dedispersion filtering work out properly.
635 delta = target_freq - self.frequency
636 self.frequency = target_freq
637 self.observing_freq += delta
639 # Now that we're adjusted, compute a new dispfilter, and
640 # set the taps for the FFT filter.
641 ntaps = self.compute_disp_ntaps(self.dm, self.bw, self.observing_freq)
642 self.disp_taps = Numeric.zeros(ntaps, Numeric.Complex64)
643 self.compute_dispfilter(self.dm,self.doppler,self.bw,
645 self.dispfilt.set_taps(self.disp_taps)
651 # Callback for gain-setting slider
652 def set_gain(self, gain):
653 self.myform['gain'].set_value(gain) # update displayed value
654 self.subdev.set_gain(gain)
657 def set_volume(self, vol):
658 self.myform['volume'].set_value(vol)
659 self.volume.set_k((10**(vol/10))/8192)
661 # Callback for spectral-averaging slider
662 def set_averaging(self, avval):
663 self.myform['average'].set_value(avval)
664 self.scope.set_avg_alpha(1.0/(avval))
665 self.scope.set_average(True)
667 def set_folder_averaging(self, avval):
668 self.myform['foldavg'].set_value(avval)
669 self.folder_iir.set_taps(1.0/avval)
671 # Timer callback to update LMST display
672 def lmst_timeout(self):
673 self.locality.date = ephem.now()
674 sidtime = self.locality.sidereal_time()
675 self.myform['lmst_high'].set_value(str(ephem.hours(sidtime)))
678 # Turn recording on/off
679 # Called-back by "Recording" button
681 def toggle_recording(self):
682 # Pick up current LMST
683 self.locality.date = ephem.now()
684 sidtime = self.locality.sidereal_time()
686 # Pick up localtime, for generating filenames
687 foo = time.localtime()
689 # Generate filenames for both data and header file
690 filename = "%04d%02d%02d%02d%02d.pdat" % (foo.tm_year, foo.tm_mon,
691 foo.tm_mday, foo.tm_hour, foo.tm_min)
692 hdrfilename = "%04d%02d%02d%02d%02d.phdr" % (foo.tm_year, foo.tm_mon,
693 foo.tm_mday, foo.tm_hour, foo.tm_min)
695 # Current recording? Flip state
696 if (self.recording_state == True):
697 self.recording_state = False
698 self.record_control.SetLabel("Recording baseband: Off ")
699 self.recording.close()
702 self.recording_state = True
703 self.record_control.SetLabel("Recording baseband to: "+filename)
705 # Cause gr_file_sink object to accept new filename
706 # note use of self.prefix--filename prefix from
707 # command line (defaults to ./)
709 self.recording.open (self.prefix+filename)
712 # We open the header file as a regular file, write header data,
714 hdrf = open(self.prefix+hdrfilename, "w")
715 hdrf.write("receiver center frequency: "+str(self.frequency)+"\n")
716 hdrf.write("observing frequency: "+str(self.observing_freq)+"\n")
717 hdrf.write("DM: "+str(self.dm)+"\n")
718 hdrf.write("doppler: "+str(self.doppler)+"\n")
720 hdrf.write("sidereal: "+str(ephem.hours(sidtime))+"\n")
721 hdrf.write("bandwidth: "+str(self.u.adc_freq() / self.u.decim_rate())+"\n")
722 hdrf.write("sample type: complex_char\n")
723 hdrf.write("sample size: "+str(gr.sizeof_char*2)+"\n")
726 # Turn recording on/off
727 # Called-back by "Recording" button
729 def toggle_pulse_recording(self):
730 # Pick up current LMST
731 self.locality.date = ephem.now()
732 sidtime = self.locality.sidereal_time()
734 # Pick up localtime, for generating filenames
735 foo = time.localtime()
737 # Generate filenames for both data and header file
738 filename = "%04d%02d%02d%02d%02d.padat" % (foo.tm_year, foo.tm_mon,
739 foo.tm_mday, foo.tm_hour, foo.tm_min)
740 hdrfilename = "%04d%02d%02d%02d%02d.pahdr" % (foo.tm_year, foo.tm_mon,
741 foo.tm_mday, foo.tm_hour, foo.tm_min)
743 # Current recording? Flip state
744 if (self.pulse_recording_state == True):
745 self.pulse_recording_state = False
746 self.record_pulse_control.SetLabel("Recording pulses: Off ")
747 self.pulse_recording.close()
750 self.pulse_recording_state = True
751 self.record_pulse_control.SetLabel("Recording pulses to: "+filename)
753 # Cause gr_file_sink object to accept new filename
754 # note use of self.prefix--filename prefix from
755 # command line (defaults to ./)
757 self.pulse_recording.open (self.prefix+filename)
760 # We open the header file as a regular file, write header data,
762 hdrf = open(self.prefix+hdrfilename, "w")
763 hdrf.write("receiver center frequency: "+str(self.frequency)+"\n")
764 hdrf.write("observing frequency: "+str(self.observing_freq)+"\n")
765 hdrf.write("DM: "+str(self.dm)+"\n")
766 hdrf.write("doppler: "+str(self.doppler)+"\n")
767 hdrf.write("pulse rate: "+str(self.pulse_freq)+"\n")
768 hdrf.write("pulse sps: "+str(self.pulse_freq*self.folding)+"\n")
769 hdrf.write("file sps: "+str(self.folder_input_rate)+"\n")
771 hdrf.write("sidereal: "+str(ephem.hours(sidtime))+"\n")
772 hdrf.write("bandwidth: "+str(self.u.adc_freq() / self.u.decim_rate())+"\n")
773 hdrf.write("sample type: short\n")
774 hdrf.write("sample size: 1\n")
777 # We get called at startup, and whenever the GUI "Set Folding params"
780 def set_folding_params(self):
781 if (self.pulse_freq <= 0):
784 # Compute required sample rate
785 self.sample_rate = int(self.pulse_freq*self.folding)
787 # And the implied decimation rate
788 required_decimation = int(self.folder_input_rate / self.sample_rate)
790 # We also compute a new FFT comb filter, based on the expected
791 # spectral profile of our pulse parameters
793 # FFT-based comb filter
795 N_COMB_TAPS=int(self.sample_rate*4)
796 if N_COMB_TAPS > 2000:
798 self.folder_comb_taps = Numeric.zeros(N_COMB_TAPS,Numeric.Complex64)
799 fincr = (self.sample_rate)/float(N_COMB_TAPS)
800 for i in range(0,len(self.folder_comb_taps)):
801 self.folder_comb_taps[i] = complex(0.0, 0.0)
804 harmonics = [1.0,2.0,3.0,4.0,5.0,6.0,7.0]
805 for i in range(0,len(self.folder_comb_taps)/2):
806 for j in range(0,len(harmonics)):
807 if abs(freq - harmonics[j]*self.pulse_freq) <= fincr:
808 self.folder_comb_taps[i] = complex(4.0, 0.0)
809 if harmonics[j] == 1.0:
810 self.folder_comb_taps[i] = complex(8.0, 0.0)
813 if self.enable_comb_filter == True:
814 # Set the just-computed FFT comb filter taps
815 self.folder_comb.set_taps(self.folder_comb_taps)
817 # And compute a new decimated bandpass filter, to go in front
818 # of the comb. Primary function is to decimate and filter down
819 # to an exact-ish multiple of the target pulse rate
821 self.folding_taps = gr.firdes_band_pass (1.0, self.folder_input_rate,
822 0.10, self.sample_rate/2, 10,
823 gr.firdes.WIN_HAMMING)
825 # Set the computed taps for the bandpass/decimate filter
826 self.folder_bandpass.set_taps (self.folding_taps)
828 # Record a spectral "hit" of a possible pulsar spectral profile
830 def record_hit(self,hits, hcavg, hcmax):
831 # Pick up current LMST
832 self.locality.date = ephem.now()
833 sidtime = self.locality.sidereal_time()
835 # Pick up localtime, for generating filenames
836 foo = time.localtime()
838 # Generate filenames for both data and header file
839 hitfilename = "%04d%02d%02d%02d.phit" % (foo.tm_year, foo.tm_mon,
840 foo.tm_mday, foo.tm_hour)
842 hitf = open(self.prefix+hitfilename, "a")
843 hitf.write("receiver center frequency: "+str(self.frequency)+"\n")
844 hitf.write("observing frequency: "+str(self.observing_freq)+"\n")
845 hitf.write("DM: "+str(self.dm)+"\n")
846 hitf.write("doppler: "+str(self.doppler)+"\n")
848 hitf.write("sidereal: "+str(ephem.hours(sidtime))+"\n")
849 hitf.write("bandwidth: "+str(self.u.adc_freq() / self.u.decim_rate())+"\n")
850 hitf.write("spectral peaks: "+str(hits)+"\n")
851 hitf.write("HCM: "+str(hcavg)+" "+str(hcmax)+"\n")
854 # This is a callback used by ra_fftsink.py (passed on creation of
856 # Whenever the user moves the cursor within the FFT display, this
857 # shows the coordinate data
859 def xydfunc(self,xyv):
860 s = "%.6fHz\n%.3fdB" % (xyv[0], xyv[1])
861 if self.lowpass >= 500:
862 s = "%.6fHz\n%.3fdB" % (xyv[0]*1000, xyv[1])
864 self.myform['spec_data'].set_value(s)
866 # This is another callback used by ra_fftsink.py (passed on creation
867 # of ra_fftsink). We pass this as our "calibrator" function, but
868 # we create interesting side-effects in the GUI.
870 # This function finds peaks in the FFT output data, and reports
871 # on them through the "Best" text object in the GUI
872 # It also computes the Harmonic Compliance Measure (HCM), and displays
875 def pulsarfunc(self,d,l):
877 incr = float(self.lowpass)/float(l)
884 # First, we need to find the average signal level
887 if (i * incr) > self.lowest_freq and (i*incr) < (self.lowpass-2):
890 # Set average signal level
895 # Then we find candidates that are greater than the user-supplied
898 # We try to cluster "hits" whose whole-number frequency is the
899 # same, and compute an average "hit" frequency.
907 # If frequency within bounds, and the (dB-avg) value is above our
909 if freq > self.lowest_freq and freq < self.lowpass-2 and (d[i] - avg) > self.threshold:
910 # If we're finding a new whole-number frequency
911 if lastint != int(freq):
912 # Record "center" of this hit, if this is a new hit
914 s2 += "%5.3fHz " % (freqavg/intcnt)
915 hits.append(freqavg/intcnt)
927 s2 += "%5.3fHz " % (freqavg/intcnt)
928 hits.append(freqavg/intcnt)
931 # Compute the HCM, by dividing each of the "hits" by each of the
932 # other hits, and comparing the difference between a "perfect"
933 # harmonic, and the observed frequency ratio.
940 for i in range(1,len(hits)):
941 meas = hits[i]/hits[0] - int(hits[i]/hits[0])
942 if abs((hits[i]-hits[i-1])-hits[0]) < 0.1:
943 avg_dist += hits[i]-hits[i-1]
945 if meas > 0.98 and meas < 1.0:
948 if meas >= max_measure:
958 s3="\nHCM: Avg %5.3fHz(%d) Max %5.3fHz Dist %5.3fHz(%d)" % (measure,mcnt,max_measure, avg_dist, acnt)
959 if max_measure < 0.5 and len(hits) >= 2:
960 self.record_hit(hits, measure, max_measure)
961 self.avg_dist = avg_dist
964 s4="\nAvg dB: %4.2f" % avg
965 self.myform['best_pulse'].set_value("("+s2+")"+s3+s4)
967 # Since we are nominally a calibrator function for ra_fftsink, we
968 # simply return what they sent us, untouched. A "real" calibrator
969 # function could monkey with the data before returning it to the
970 # FFT display function.
974 # Callback for the "DM" gui object
976 # We call compute_dispfilter() as appropriate to compute a new filter,
977 # and then set that new filter into self.dispfilt.
982 ntaps = self.compute_disp_ntaps (self.dm, self.bw, self.observing_freq)
983 self.disp_taps = Numeric.zeros(ntaps, Numeric.Complex64)
984 self.compute_dispfilter(self.dm,self.doppler,self.bw,self.observing_freq)
985 self.dispfilt.set_taps(self.disp_taps)
986 self.myform['DM'].set_value(dm)
990 # Callback for the "Doppler" gui object
992 # We call compute_dispfilter() as appropriate to compute a new filter,
993 # and then set that new filter into self.dispfilt.
995 def set_doppler(self,doppler):
996 self.doppler = doppler
998 ntaps = self.compute_disp_ntaps (self.dm, self.bw, self.observing_freq)
999 self.disp_taps = Numeric.zeros(ntaps, Numeric.Complex64)
1000 self.compute_dispfilter(self.dm,self.doppler,self.bw,self.observing_freq)
1001 self.dispfilt.set_taps(self.disp_taps)
1002 self.myform['Doppler'].set_value(doppler)
1006 # Compute a de-dispersion filter
1007 # From Hankins, et al, 1975
1009 # This code translated from dedisp_filter.c from Swinburne
1010 # pulsar software repository
1012 def compute_dispfilter(self,dm,doppler,bw,centerfreq):
1013 npts = len(self.disp_taps)
1014 tmp = Numeric.zeros(npts, Numeric.Complex64)
1015 M_PI = 3.14159265358
1019 # Because astronomers are a crazy bunch, the "standard" calcultion
1020 # is in Mhz, rather than Hz
1022 centerfreq = centerfreq / 1.0e6
1025 isign = int(bw / abs (bw))
1027 # Center frequency may be doppler shifted
1028 cfreq = centerfreq / doppler
1030 # As well as the bandwidth..
1031 bandwidth = bw / doppler
1033 # Bandwidth divided among bins
1034 binwidth = bandwidth / npts
1036 # Delay is an "extra" parameter, in usecs, and largely
1037 # untested in the Swinburne code.
1040 # This determines the coefficient of the frequency response curve
1041 # Linear in DM, but quadratic in center frequency
1042 coeff = isign * 2.0*M_PI * DM / (cfreq*cfreq)
1046 for i in range(0,int(npts/2)):
1047 freq = (n + 0.5) * binwidth
1048 phi = coeff*freq*freq/(cfreq+freq) + (2.0*M_PI*freq*delay)
1049 tmp[i] = complex(math.cos(phi), math.sin(phi))
1055 for i in range(int(npts/2),npts):
1056 freq = (n + 0.5) * binwidth
1057 phi = coeff*freq*freq/(cfreq+freq) + (2.0*M_PI*freq*delay)
1058 tmp[i] = complex(math.cos(phi), math.sin(phi))
1061 self.disp_taps = numpy.fft.ifft(tmp)
1062 return(self.disp_taps)
1065 # Compute minimum number of taps required in de-dispersion FFT filter
1067 def compute_disp_ntaps(self,dm,bw,freq):
1069 # Dt calculations are in Mhz, rather than Hz
1070 # crazy astronomers....
1074 f_lower = mfreq-(mbw/2)
1075 f_upper = mfreq+(mbw/2)
1077 # Compute smear time
1078 Dt = dm/2.41e-4 * (1.0/(f_lower*f_lower)-1.0/(f_upper*f_upper))
1080 # ntaps is now bandwidth*smeartime
1081 # Should be bandwidth*smeartime*2, but the Gnu Radio FFT filter
1082 # already expands it by a factor of 2
1089 app = stdgui.stdapp(app_flow_graph, "RADIO ASTRONOMY PULSAR RECEIVER: $Revision$", nstatus=1)
1092 if __name__ == '__main__':