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 stdgui2, 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, frame, panel, vbox, argv)
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 parser.add_option("-N", "--num_pulses", default=1, type="eng_float", help="Number of display pulses")
89 (options, args) = parser.parse_args()
94 self.show_debug_info = True
96 self.reflevel = options.reflevel
97 self.divbase = options.divbase
98 self.division = options.division
99 self.audiodev = options.audio_source
100 self.mult = int(options.num_pulses)
102 # Low-pass cutoff for post-detector filter
103 # Set to 100Hz usually, since lots of pulsars fit in this
105 self.lowpass = options.lowpass
107 # What is lowest valid frequency bin in post-detector FFT?
108 # There's some pollution very close to DC
109 self.lowest_freq = options.lowest
111 # What (dB) threshold to use in determining spectral candidates
112 self.threshold = options.threshold
114 # Filename prefix for recording file
115 self.prefix = options.prefix
117 # Dispersion Measure (DM)
120 # Doppler shift, as a ratio
121 # 1.0 == no doppler shift
122 # 1.005 == a little negative shift
123 # 0.995 == a little positive shift
124 self.doppler = options.doppler
127 # Input frequency and observing frequency--not necessarily the
128 # same thing, if we're looking at the IF of some downconverter
129 # that's ahead of the USRP and daughtercard. This distinction
130 # is important in computing the correct de-dispersion filter.
132 self.frequency = options.freq
133 if options.observing <= 0:
134 self.observing_freq = options.freq
136 self.observing_freq = options.observing
139 self.u = usrp.source_c(decim_rate=options.decim)
140 self.u.set_mux(usrp.determine_rx_mux_value(self.u, options.rx_subdev_spec))
143 # Recording file, in case we ever need to record baseband data
145 self.recording = gr.file_sink(gr.sizeof_char, "/dev/null")
146 self.recording_state = False
148 self.pulse_recording = gr.file_sink(gr.sizeof_short, "/dev/null")
149 self.pulse_recording_state = False
152 # We come up with recording turned off, but the user may
153 # request recording later on
154 self.recording.close()
155 self.pulse_recording.close()
158 # Need these two for converting 12-bit baseband signals to 8-bit
160 self.tofloat = gr.complex_to_float()
161 self.tochar = gr.float_to_char()
163 # Need this for recording pulses (post-detector)
164 self.toshort = gr.float_to_short()
168 # The spectral measurer sets this when it has a valid
169 # average spectral peak-to-peak distance
170 # We can then use this to program the parameters for the epoch folder
172 # We set a sentimental value here
173 self.pulse_freq = options.pulsefreq
175 # Folder runs at this raw sample rate
176 self.folder_input_rate = 20000
178 # Each pulse in the epoch folder is sampled at 128 times the nominal
184 # Try to find candidate parameters for rational resampler
188 for i in range(20,300):
189 input_rate = self.folder_input_rate
190 output_rate = int(self.pulse_freq * i)
191 interp = gru.lcm(input_rate, output_rate) / input_rate
192 decim = gru.lcm(input_rate, output_rate) / output_rate
193 if (interp < 500 and decim < 250000):
196 # We didn't find anything, bail!
197 if (len(candidates) < 1):
198 print "Couldn't converge on resampler parameters"
202 # Now try to find candidate with the least sampling error
206 diff = self.pulse_freq * i
207 diff = diff - int(diff)
213 input_rate = self.folder_input_rate
214 output_rate = int(self.pulse_freq * save_i)
216 # Compute new interp and decim, based on best candidate
217 interp = gru.lcm(input_rate, output_rate) / input_rate
218 decim = gru.lcm(input_rate, output_rate) / output_rate
220 # Save optimized folding parameters, used later
221 self.folding = save_i
222 self.interp = int(interp)
223 self.decim = int(decim)
225 # So that we can view N pulses in the pulse viewer window
228 # determine the daughterboard subdevice we're using
229 self.subdev = usrp.selected_subdev(self.u, options.rx_subdev_spec)
230 self.cardtype = self.u.daughterboard_id(0)
232 # Compute raw input rate
233 input_rate = self.u.adc_freq() / self.u.decim_rate()
235 # BW==input_rate for complex data
239 # Set baseband filter bandwidth if DBS_RX:
241 if self.cardtype == usrp_dbid.DBS_RX:
245 self.subdev.set_bw(lbw)
248 # We use this as a crude volume control for the audio output
250 #self.volume = gr.multiply_const_ff(10**(-1))
254 # Create location data for ephem package
256 self.locality = ephem.Observer()
257 self.locality.long = str(options.longitude)
258 self.locality.lat = str(options.latitude)
261 # What is the post-detector LPF cutoff for the FFT?
263 PULSAR_MAX_FREQ=int(options.lowpass)
265 # First low-pass filters down to input_rate/FIRST_FACTOR
266 # and decimates appropriately
267 FIRST_FACTOR=int(input_rate/(self.folder_input_rate/2))
268 first_filter = gr.firdes.low_pass (1.0,
270 input_rate/FIRST_FACTOR,
271 input_rate/(FIRST_FACTOR*20),
272 gr.firdes.WIN_HAMMING)
274 # Second filter runs at the output rate of the first filter,
275 # And low-pass filters down to PULSAR_MAX_FREQ*10
277 second_input_rate = int(input_rate/(FIRST_FACTOR/2))
278 second_filter = gr.firdes.band_pass(1.0, second_input_rate,
282 gr.firdes.WIN_HAMMING)
284 # Third filter runs at PULSAR_MAX_FREQ*20
285 # and filters down to PULSAR_MAX_FREQ
287 third_input_rate = PULSAR_MAX_FREQ*20
288 third_filter = gr.firdes_band_pass(1.0, third_input_rate,
289 0.10, PULSAR_MAX_FREQ,
290 PULSAR_MAX_FREQ/10.0,
291 gr.firdes.WIN_HAMMING)
295 # Create the appropriate FFT scope
297 self.scope = ra_fftsink.ra_fft_sink_f (panel,
298 fft_size=int(options.fft_size), sample_rate=PULSAR_MAX_FREQ*2,
299 title="Post-detector spectrum",
300 ofunc=self.pulsarfunc, xydfunc=self.xydfunc, fft_rate=200)
303 # Tell scope we're looking from DC to PULSAR_MAX_FREQ
305 self.scope.set_baseband_freq (0.0)
309 # Setup stripchart for showing pulse profiles
311 hz = "%5.3fHz " % self.pulse_freq
312 per = "(%5.3f sec)" % (1.0/self.pulse_freq)
313 sr = "%d sps" % (int(self.pulse_freq*self.folding))
314 times = " %d Pulse Intervals" % self.mult
315 self.chart = ra_stripchartsink.stripchart_sink_f (panel,
317 stripsize=self.folding*FOLD_MULT, parallel=True, title="Pulse Profiles: "+hz+per+times,
318 xlabel="Seconds @ "+sr, ylabel="Level", autoscale=True,
319 divbase=self.divbase, scaling=1.0/(self.folding*self.pulse_freq))
320 self.chart.set_ref_level(self.reflevel)
321 self.chart.set_y_per_div(self.division)
323 # De-dispersion filter setup
325 # Do this here, just before creating the filter
326 # that will use the taps.
328 ntaps = self.compute_disp_ntaps(self.dm,self.bw,self.observing_freq)
330 # Taps for the de-dispersion filter
331 self.disp_taps = Numeric.zeros(ntaps,Numeric.Complex64)
333 # Compute the de-dispersion filter now
334 self.compute_dispfilter(self.dm,self.doppler,
335 self.bw,self.observing_freq)
338 # Call constructors for receive chains
342 # Now create the FFT filter using the computed taps
343 self.dispfilt = gr.fft_filter_ccc(1, self.disp_taps)
348 #print "input_rate ", second_input_rate, "audiodev ", self.audiodev
349 #self.audio = audio.sink(second_input_rate, self.audiodev)
352 # The three post-detector filters
353 # Done this way to allow an audio path (up to 10Khz)
354 # ...and also because going from xMhz down to ~100Hz
355 # In a single filter doesn't seem to work.
357 self.first = gr.fir_filter_fff (FIRST_FACTOR/2, first_filter)
359 p = second_input_rate / (PULSAR_MAX_FREQ*20)
360 self.second = gr.fir_filter_fff (int(p), second_filter)
361 self.third = gr.fir_filter_fff (10, third_filter)
364 self.detector = gr.complex_to_mag_squared()
366 self.enable_comb_filter = False
367 # Epoch folder comb filter
368 if self.enable_comb_filter == True:
369 bogtaps = Numeric.zeros(512, Numeric.Float64)
370 self.folder_comb = gr.fft_filter_ccc(1,bogtaps)
373 self.folder_rr = blks2.rational_resampler_fff(self.interp, self.decim)
375 # Epoch folder bandpass
376 bogtaps = Numeric.zeros(1, Numeric.Float64)
377 self.folder_bandpass = gr.fir_filter_fff (1, bogtaps)
379 # Epoch folder F2C/C2F
380 self.folder_f2c = gr.float_to_complex()
381 self.folder_c2f = gr.complex_to_float()
384 self.folder_s2p = gr.serial_to_parallel (gr.sizeof_float,
385 self.folding*FOLD_MULT)
387 # Epoch folder IIR Filter (produces average pulse profiles)
388 self.folder_iir = gr.single_pole_iir_filter_ff(1.0/options.favg,
389 self.folding*FOLD_MULT)
392 # Set all the epoch-folder goop up
394 self.set_folding_params()
397 # Start connecting configured modules in the receive chain
400 # Connect raw USRP to de-dispersion filter, detector
401 self.connect(self.u, self.dispfilt, self.detector)
403 # Connect detector output to FIR LPF
404 # in two stages, followed by the FFT scope
405 self.connect(self.detector, self.first,
406 self.second, self.third, self.scope)
408 # Connect audio output
409 #self.connect(self.first, self.volume)
410 #self.connect(self.volume, (self.audio, 0))
411 #self.connect(self.volume, (self.audio, 1))
413 # Connect epoch folder
414 if self.enable_comb_filter == True:
415 self.connect (self.first, self.folder_bandpass, self.folder_rr,
417 self.folder_comb, self.folder_c2f,
418 self.folder_s2p, self.folder_iir,
422 self.connect (self.first, self.folder_bandpass, self.folder_rr,
423 self.folder_s2p, self.folder_iir, self.chart)
425 # Connect baseband recording file (initially /dev/null)
426 self.connect(self.u, self.tofloat, self.tochar, self.recording)
428 # Connect pulse recording file (initially /dev/null)
429 self.connect(self.first, self.toshort, self.pulse_recording)
432 # Build the GUI elements
434 self._build_gui(vbox)
436 # Make GUI agree with command-line
437 self.myform['average'].set_value(int(options.avg))
438 self.myform['foldavg'].set_value(int(options.favg))
441 # Make spectral averager agree with command line
442 if options.avg != 1.0:
443 self.scope.set_avg_alpha(float(1.0/options.avg))
444 self.scope.set_average(True)
449 if options.gain is None:
450 # if no gain was specified, use the mid-point in dB
451 g = self.subdev.gain_range()
452 options.gain = float(g[0]+g[1])/2
454 if options.freq is None:
455 # if no freq was specified, use the mid-point
456 r = self.subdev.freq_range()
457 options.freq = float(r[0]+r[1])/2
459 self.set_gain(options.gain)
460 #self.set_volume(-10.0)
462 if not(self.set_freq(options.freq)):
463 self._set_status_msg("Failed to set initial frequency")
465 self.myform['decim'].set_value(self.u.decim_rate())
466 self.myform['fs@usb'].set_value(self.u.adc_freq() / self.u.decim_rate())
467 self.myform['dbname'].set_value(self.subdev.name())
468 self.myform['DM'].set_value(self.dm)
469 self.myform['Doppler'].set_value(self.doppler)
472 # Start the timer that shows current LMST on the GUI
474 self.lmst_timer.Start(1000)
477 def _set_status_msg(self, msg):
478 self.frame.GetStatusBar().SetStatusText(msg, 0)
480 def _build_gui(self, vbox):
482 def _form_set_freq(kv):
483 return self.set_freq(kv['freq'])
485 def _form_set_dm(kv):
486 return self.set_dm(kv['DM'])
488 def _form_set_doppler(kv):
489 return self.set_doppler(kv['Doppler'])
491 # Position the FFT or Waterfall
492 vbox.Add(self.scope.win, 5, wx.EXPAND)
493 vbox.Add(self.chart.win, 5, wx.EXPAND)
495 # add control area at the bottom
496 self.myform = myform = form.form()
497 hbox = wx.BoxSizer(wx.HORIZONTAL)
498 hbox.Add((7,0), 0, wx.EXPAND)
499 vbox1 = wx.BoxSizer(wx.VERTICAL)
500 myform['freq'] = form.float_field(
501 parent=self.panel, sizer=vbox1, label="Center freq", weight=1,
502 callback=myform.check_input_and_call(_form_set_freq, self._set_status_msg))
504 vbox1.Add((3,0), 0, 0)
506 # To show current Local Mean Sidereal Time
507 myform['lmst_high'] = form.static_text_field(
508 parent=self.panel, sizer=vbox1, label="Current LMST", weight=1)
509 vbox1.Add((3,0), 0, 0)
511 # To show current spectral cursor data
512 myform['spec_data'] = form.static_text_field(
513 parent=self.panel, sizer=vbox1, label="Pulse Freq", weight=1)
514 vbox1.Add((3,0), 0, 0)
516 # To show best pulses found in FFT output
517 myform['best_pulse'] = form.static_text_field(
518 parent=self.panel, sizer=vbox1, label="Best freq", weight=1)
519 vbox1.Add((3,0), 0, 0)
521 vboxBogus = wx.BoxSizer(wx.VERTICAL)
522 vboxBogus.Add ((2,0), 0, wx.EXPAND)
523 vbox2 = wx.BoxSizer(wx.VERTICAL)
524 g = self.subdev.gain_range()
525 myform['gain'] = form.slider_field(parent=self.panel, sizer=vbox2, label="RF Gain",
527 min=int(g[0]), max=int(g[1]),
528 callback=self.set_gain)
530 vbox2.Add((6,0), 0, 0)
531 myform['average'] = form.slider_field(parent=self.panel, sizer=vbox2,
532 label="Spectral Averaging", weight=1, min=1, max=200, callback=self.set_averaging)
533 vbox2.Add((6,0), 0, 0)
534 myform['foldavg'] = form.slider_field(parent=self.panel, sizer=vbox2,
535 label="Folder Averaging", weight=1, min=1, max=20, callback=self.set_folder_averaging)
536 vbox2.Add((6,0), 0, 0)
537 #myform['volume'] = form.quantized_slider_field(parent=self.panel, sizer=vbox2,
538 #label="Audio Volume", weight=1, range=(-20, 0, 0.5), callback=self.set_volume)
539 #vbox2.Add((6,0), 0, 0)
540 myform['DM'] = form.float_field(
541 parent=self.panel, sizer=vbox2, label="DM", weight=1,
542 callback=myform.check_input_and_call(_form_set_dm))
543 vbox2.Add((6,0), 0, 0)
544 myform['Doppler'] = form.float_field(
545 parent=self.panel, sizer=vbox2, label="Doppler", weight=1,
546 callback=myform.check_input_and_call(_form_set_doppler))
547 vbox2.Add((6,0), 0, 0)
550 # Baseband recording control
551 buttonbox = wx.BoxSizer(wx.HORIZONTAL)
552 self.record_control = form.button_with_callback(self.panel,
553 label="Recording baseband: Off ",
554 callback=self.toggle_recording)
555 self.record_pulse_control = form.button_with_callback(self.panel,
556 label="Recording pulses: Off ",
557 callback=self.toggle_pulse_recording)
559 buttonbox.Add(self.record_control, 0, wx.CENTER)
560 buttonbox.Add(self.record_pulse_control, 0, wx.CENTER)
561 vbox.Add(buttonbox, 0, wx.CENTER)
562 hbox.Add(vbox1, 0, 0)
563 hbox.Add(vboxBogus, 0, 0)
564 hbox.Add(vbox2, wx.ALIGN_RIGHT, 0)
565 vbox.Add(hbox, 0, wx.EXPAND)
567 self._build_subpanel(vbox)
569 self.lmst_timer = wx.PyTimer(self.lmst_timeout)
573 def _build_subpanel(self, vbox_arg):
574 # build a secondary information panel (sometimes hidden)
576 # FIXME figure out how to have this be a subpanel that is always
577 # created, but has its visibility controlled by foo.Show(True/False)
579 if not(self.show_debug_info):
586 #panel = wx.Panel(self.panel, -1)
587 #vbox = wx.BoxSizer(wx.VERTICAL)
589 hbox = wx.BoxSizer(wx.HORIZONTAL)
591 myform['decim'] = form.static_float_field(
592 parent=panel, sizer=hbox, label="Decim")
595 myform['fs@usb'] = form.static_float_field(
596 parent=panel, sizer=hbox, label="Fs@USB")
599 myform['dbname'] = form.static_text_field(
600 parent=panel, sizer=hbox)
603 myform['baseband'] = form.static_float_field(
604 parent=panel, sizer=hbox, label="Analog BB")
607 myform['ddc'] = form.static_float_field(
608 parent=panel, sizer=hbox, label="DDC")
611 vbox.Add(hbox, 0, wx.EXPAND)
615 def set_freq(self, target_freq):
617 Set the center frequency we're interested in.
619 @param target_freq: frequency in Hz
622 Tuning is a two step process. First we ask the front-end to
623 tune as close to the desired frequency as it can. Then we use
624 the result of that operation and our target_frequency to
625 determine the value for the digital down converter.
627 r = usrp.tune(self.u, 0, self.subdev, target_freq)
630 self.myform['freq'].set_value(target_freq) # update displayed value
631 self.myform['baseband'].set_value(r.baseband_freq)
632 self.myform['ddc'].set_value(r.dxc_freq)
633 # Adjust self.frequency, and self.observing_freq
634 # We pick up the difference between the current self.frequency
635 # and the just-programmed one, and use this to adjust
636 # self.observing_freq. We have to do it this way to
637 # make the dedispersion filtering work out properly.
638 delta = target_freq - self.frequency
639 self.frequency = target_freq
640 self.observing_freq += delta
642 # Now that we're adjusted, compute a new dispfilter, and
643 # set the taps for the FFT filter.
644 ntaps = self.compute_disp_ntaps(self.dm, self.bw, self.observing_freq)
645 self.disp_taps = Numeric.zeros(ntaps, Numeric.Complex64)
646 self.compute_dispfilter(self.dm,self.doppler,self.bw,
648 self.dispfilt.set_taps(self.disp_taps)
654 # Callback for gain-setting slider
655 def set_gain(self, gain):
656 self.myform['gain'].set_value(gain) # update displayed value
657 self.subdev.set_gain(gain)
660 #def set_volume(self, vol):
661 #self.myform['volume'].set_value(vol)
662 #self.volume.set_k((10**(vol/10))/8192)
664 # Callback for spectral-averaging slider
665 def set_averaging(self, avval):
666 self.myform['average'].set_value(avval)
667 self.scope.set_avg_alpha(1.0/(avval))
668 self.scope.set_average(True)
670 def set_folder_averaging(self, avval):
671 self.myform['foldavg'].set_value(avval)
672 self.folder_iir.set_taps(1.0/avval)
674 # Timer callback to update LMST display
675 def lmst_timeout(self):
676 self.locality.date = ephem.now()
677 sidtime = self.locality.sidereal_time()
678 self.myform['lmst_high'].set_value(str(ephem.hours(sidtime)))
681 # Turn recording on/off
682 # Called-back by "Recording" button
684 def toggle_recording(self):
685 # Pick up current LMST
686 self.locality.date = ephem.now()
687 sidtime = self.locality.sidereal_time()
689 # Pick up localtime, for generating filenames
690 foo = time.localtime()
692 # Generate filenames for both data and header file
693 filename = "%04d%02d%02d%02d%02d.pdat" % (foo.tm_year, foo.tm_mon,
694 foo.tm_mday, foo.tm_hour, foo.tm_min)
695 hdrfilename = "%04d%02d%02d%02d%02d.phdr" % (foo.tm_year, foo.tm_mon,
696 foo.tm_mday, foo.tm_hour, foo.tm_min)
698 # Current recording? Flip state
699 if (self.recording_state == True):
700 self.recording_state = False
701 self.record_control.SetLabel("Recording baseband: Off ")
702 self.recording.close()
705 self.recording_state = True
706 self.record_control.SetLabel("Recording baseband to: "+filename)
708 # Cause gr_file_sink object to accept new filename
709 # note use of self.prefix--filename prefix from
710 # command line (defaults to ./)
712 self.recording.open (self.prefix+filename)
715 # We open the header file as a regular file, write header data,
717 hdrf = open(self.prefix+hdrfilename, "w")
718 hdrf.write("receiver center frequency: "+str(self.frequency)+"\n")
719 hdrf.write("observing frequency: "+str(self.observing_freq)+"\n")
720 hdrf.write("DM: "+str(self.dm)+"\n")
721 hdrf.write("doppler: "+str(self.doppler)+"\n")
723 hdrf.write("sidereal: "+str(ephem.hours(sidtime))+"\n")
724 hdrf.write("bandwidth: "+str(self.u.adc_freq() / self.u.decim_rate())+"\n")
725 hdrf.write("sample type: complex_char\n")
726 hdrf.write("sample size: "+str(gr.sizeof_char*2)+"\n")
729 # Turn recording on/off
730 # Called-back by "Recording" button
732 def toggle_pulse_recording(self):
733 # Pick up current LMST
734 self.locality.date = ephem.now()
735 sidtime = self.locality.sidereal_time()
737 # Pick up localtime, for generating filenames
738 foo = time.localtime()
740 # Generate filenames for both data and header file
741 filename = "%04d%02d%02d%02d%02d.padat" % (foo.tm_year, foo.tm_mon,
742 foo.tm_mday, foo.tm_hour, foo.tm_min)
743 hdrfilename = "%04d%02d%02d%02d%02d.pahdr" % (foo.tm_year, foo.tm_mon,
744 foo.tm_mday, foo.tm_hour, foo.tm_min)
746 # Current recording? Flip state
747 if (self.pulse_recording_state == True):
748 self.pulse_recording_state = False
749 self.record_pulse_control.SetLabel("Recording pulses: Off ")
750 self.pulse_recording.close()
753 self.pulse_recording_state = True
754 self.record_pulse_control.SetLabel("Recording pulses to: "+filename)
756 # Cause gr_file_sink object to accept new filename
757 # note use of self.prefix--filename prefix from
758 # command line (defaults to ./)
760 self.pulse_recording.open (self.prefix+filename)
763 # We open the header file as a regular file, write header data,
765 hdrf = open(self.prefix+hdrfilename, "w")
766 hdrf.write("receiver center frequency: "+str(self.frequency)+"\n")
767 hdrf.write("observing frequency: "+str(self.observing_freq)+"\n")
768 hdrf.write("DM: "+str(self.dm)+"\n")
769 hdrf.write("doppler: "+str(self.doppler)+"\n")
770 hdrf.write("pulse rate: "+str(self.pulse_freq)+"\n")
771 hdrf.write("pulse sps: "+str(self.pulse_freq*self.folding)+"\n")
772 hdrf.write("file sps: "+str(self.folder_input_rate)+"\n")
774 hdrf.write("sidereal: "+str(ephem.hours(sidtime))+"\n")
775 hdrf.write("bandwidth: "+str(self.u.adc_freq() / self.u.decim_rate())+"\n")
776 hdrf.write("sample type: short\n")
777 hdrf.write("sample size: 1\n")
780 # We get called at startup, and whenever the GUI "Set Folding params"
783 def set_folding_params(self):
784 if (self.pulse_freq <= 0):
787 # Compute required sample rate
788 self.sample_rate = int(self.pulse_freq*self.folding)
790 # And the implied decimation rate
791 required_decimation = int(self.folder_input_rate / self.sample_rate)
793 # We also compute a new FFT comb filter, based on the expected
794 # spectral profile of our pulse parameters
796 # FFT-based comb filter
798 N_COMB_TAPS=int(self.sample_rate*4)
799 if N_COMB_TAPS > 2000:
801 self.folder_comb_taps = Numeric.zeros(N_COMB_TAPS,Numeric.Complex64)
802 fincr = (self.sample_rate)/float(N_COMB_TAPS)
803 for i in range(0,len(self.folder_comb_taps)):
804 self.folder_comb_taps[i] = complex(0.0, 0.0)
807 harmonics = [1.0,2.0,3.0,4.0,5.0,6.0,7.0]
808 for i in range(0,len(self.folder_comb_taps)/2):
809 for j in range(0,len(harmonics)):
810 if abs(freq - harmonics[j]*self.pulse_freq) <= fincr:
811 self.folder_comb_taps[i] = complex(4.0, 0.0)
812 if harmonics[j] == 1.0:
813 self.folder_comb_taps[i] = complex(8.0, 0.0)
816 if self.enable_comb_filter == True:
817 # Set the just-computed FFT comb filter taps
818 self.folder_comb.set_taps(self.folder_comb_taps)
820 # And compute a new decimated bandpass filter, to go in front
821 # of the comb. Primary function is to decimate and filter down
822 # to an exact-ish multiple of the target pulse rate
824 self.folding_taps = gr.firdes_band_pass (1.0, self.folder_input_rate,
825 0.10, self.sample_rate/2, 10,
826 gr.firdes.WIN_HAMMING)
828 # Set the computed taps for the bandpass/decimate filter
829 self.folder_bandpass.set_taps (self.folding_taps)
831 # Record a spectral "hit" of a possible pulsar spectral profile
833 def record_hit(self,hits, hcavg, hcmax):
834 # Pick up current LMST
835 self.locality.date = ephem.now()
836 sidtime = self.locality.sidereal_time()
838 # Pick up localtime, for generating filenames
839 foo = time.localtime()
841 # Generate filenames for both data and header file
842 hitfilename = "%04d%02d%02d%02d.phit" % (foo.tm_year, foo.tm_mon,
843 foo.tm_mday, foo.tm_hour)
845 hitf = open(self.prefix+hitfilename, "a")
846 hitf.write("receiver center frequency: "+str(self.frequency)+"\n")
847 hitf.write("observing frequency: "+str(self.observing_freq)+"\n")
848 hitf.write("DM: "+str(self.dm)+"\n")
849 hitf.write("doppler: "+str(self.doppler)+"\n")
851 hitf.write("sidereal: "+str(ephem.hours(sidtime))+"\n")
852 hitf.write("bandwidth: "+str(self.u.adc_freq() / self.u.decim_rate())+"\n")
853 hitf.write("spectral peaks: "+str(hits)+"\n")
854 hitf.write("HCM: "+str(hcavg)+" "+str(hcmax)+"\n")
857 # This is a callback used by ra_fftsink.py (passed on creation of
859 # Whenever the user moves the cursor within the FFT display, this
860 # shows the coordinate data
862 def xydfunc(self,xyv):
863 s = "%.6fHz\n%.3fdB" % (xyv[0], xyv[1])
864 if self.lowpass >= 500:
865 s = "%.6fHz\n%.3fdB" % (xyv[0]*1000, xyv[1])
867 self.myform['spec_data'].set_value(s)
869 # This is another callback used by ra_fftsink.py (passed on creation
870 # of ra_fftsink). We pass this as our "calibrator" function, but
871 # we create interesting side-effects in the GUI.
873 # This function finds peaks in the FFT output data, and reports
874 # on them through the "Best" text object in the GUI
875 # It also computes the Harmonic Compliance Measure (HCM), and displays
878 def pulsarfunc(self,d,l):
880 incr = float(self.lowpass)/float(l)
887 # First, we need to find the average signal level
890 if (i * incr) > self.lowest_freq and (i*incr) < (self.lowpass-2):
893 # Set average signal level
898 # Then we find candidates that are greater than the user-supplied
901 # We try to cluster "hits" whose whole-number frequency is the
902 # same, and compute an average "hit" frequency.
910 # If frequency within bounds, and the (dB-avg) value is above our
912 if freq > self.lowest_freq and freq < self.lowpass-2 and (d[i] - avg) > self.threshold:
913 # If we're finding a new whole-number frequency
914 if lastint != int(freq):
915 # Record "center" of this hit, if this is a new hit
917 s2 += "%5.3fHz " % (freqavg/intcnt)
918 hits.append(freqavg/intcnt)
930 s2 += "%5.3fHz " % (freqavg/intcnt)
931 hits.append(freqavg/intcnt)
934 # Compute the HCM, by dividing each of the "hits" by each of the
935 # other hits, and comparing the difference between a "perfect"
936 # harmonic, and the observed frequency ratio.
943 for i in range(1,len(hits)):
944 meas = hits[i]/hits[0] - int(hits[i]/hits[0])
945 if abs((hits[i]-hits[i-1])-hits[0]) < 0.1:
946 avg_dist += hits[i]-hits[i-1]
948 if meas > 0.98 and meas < 1.0:
951 if meas >= max_measure:
961 s3="\nHCM: Avg %5.3fHz(%d) Max %5.3fHz Dist %5.3fHz(%d)" % (measure,mcnt,max_measure, avg_dist, acnt)
962 if max_measure < 0.5 and len(hits) >= 2:
963 self.record_hit(hits, measure, max_measure)
964 self.avg_dist = avg_dist
967 s4="\nAvg dB: %4.2f" % avg
968 self.myform['best_pulse'].set_value("("+s2+")"+s3+s4)
970 # Since we are nominally a calibrator function for ra_fftsink, we
971 # simply return what they sent us, untouched. A "real" calibrator
972 # function could monkey with the data before returning it to the
973 # FFT display function.
977 # Callback for the "DM" gui object
979 # We call compute_dispfilter() as appropriate to compute a new filter,
980 # and then set that new filter into self.dispfilt.
985 ntaps = self.compute_disp_ntaps (self.dm, self.bw, self.observing_freq)
986 self.disp_taps = Numeric.zeros(ntaps, Numeric.Complex64)
987 self.compute_dispfilter(self.dm,self.doppler,self.bw,self.observing_freq)
988 self.dispfilt.set_taps(self.disp_taps)
989 self.myform['DM'].set_value(dm)
993 # Callback for the "Doppler" gui object
995 # We call compute_dispfilter() as appropriate to compute a new filter,
996 # and then set that new filter into self.dispfilt.
998 def set_doppler(self,doppler):
999 self.doppler = doppler
1001 ntaps = self.compute_disp_ntaps (self.dm, self.bw, self.observing_freq)
1002 self.disp_taps = Numeric.zeros(ntaps, Numeric.Complex64)
1003 self.compute_dispfilter(self.dm,self.doppler,self.bw,self.observing_freq)
1004 self.dispfilt.set_taps(self.disp_taps)
1005 self.myform['Doppler'].set_value(doppler)
1009 # Compute a de-dispersion filter
1010 # From Hankins, et al, 1975
1012 # This code translated from dedisp_filter.c from Swinburne
1013 # pulsar software repository
1015 def compute_dispfilter(self,dm,doppler,bw,centerfreq):
1016 npts = len(self.disp_taps)
1017 tmp = Numeric.zeros(npts, Numeric.Complex64)
1018 M_PI = 3.14159265358
1022 # Because astronomers are a crazy bunch, the "standard" calcultion
1023 # is in Mhz, rather than Hz
1025 centerfreq = centerfreq / 1.0e6
1028 isign = int(bw / abs (bw))
1030 # Center frequency may be doppler shifted
1031 cfreq = centerfreq / doppler
1033 # As well as the bandwidth..
1034 bandwidth = bw / doppler
1036 # Bandwidth divided among bins
1037 binwidth = bandwidth / npts
1039 # Delay is an "extra" parameter, in usecs, and largely
1040 # untested in the Swinburne code.
1043 # This determines the coefficient of the frequency response curve
1044 # Linear in DM, but quadratic in center frequency
1045 coeff = isign * 2.0*M_PI * DM / (cfreq*cfreq)
1049 for i in range(0,int(npts/2)):
1050 freq = (n + 0.5) * binwidth
1051 phi = coeff*freq*freq/(cfreq+freq) + (2.0*M_PI*freq*delay)
1052 tmp[i] = complex(math.cos(phi), math.sin(phi))
1058 for i in range(int(npts/2),npts):
1059 freq = (n + 0.5) * binwidth
1060 phi = coeff*freq*freq/(cfreq+freq) + (2.0*M_PI*freq*delay)
1061 tmp[i] = complex(math.cos(phi), math.sin(phi))
1064 self.disp_taps = numpy.fft.ifft(tmp)
1065 return(self.disp_taps)
1068 # Compute minimum number of taps required in de-dispersion FFT filter
1070 def compute_disp_ntaps(self,dm,bw,freq):
1072 # Dt calculations are in Mhz, rather than Hz
1073 # crazy astronomers....
1077 f_lower = mfreq-(mbw/2)
1078 f_upper = mfreq+(mbw/2)
1080 # Compute smear time
1081 Dt = dm/2.41e-4 * (1.0/(f_lower*f_lower)-1.0/(f_upper*f_upper))
1083 # ntaps is now bandwidth*smeartime
1084 # Should be bandwidth*smeartime*2, but the Gnu Radio FFT filter
1085 # already expands it by a factor of 2
1092 app = stdgui2.stdapp(app_flow_graph, "RADIO ASTRONOMY PULSAR RECEIVER: $Revision$", nstatus=1)
1095 if __name__ == '__main__':