3 # Copyright 2004,2005 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 2, 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, blks, audio
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(stdgui.gui_flow_graph):
50 def __init__(self, frame, panel, vbox, argv):
51 stdgui.gui_flow_graph.__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 (options, args) = parser.parse_args()
92 self.show_debug_info = True
94 self.reflevel = options.reflevel
95 self.divbase = options.divbase
96 self.division = options.division
98 # Low-pass cutoff for post-detector filter
99 # Set to 100Hz usually, since lots of pulsars fit in this
101 self.lowpass = options.lowpass
103 # What is lowest valid frequency bin in post-detector FFT?
104 # There's some pollution very close to DC
105 self.lowest_freq = options.lowest
107 # What (dB) threshold to use in determining spectral candidates
108 self.threshold = options.threshold
110 # Filename prefix for recording file
111 self.prefix = options.prefix
113 # Dispersion Measure (DM)
116 # Doppler shift, as a ratio
117 # 1.0 == no doppler shift
118 # 1.005 == a little negative shift
119 # 0.995 == a little positive shift
120 self.doppler = options.doppler
123 # Input frequency and observing frequency--not necessarily the
124 # same thing, if we're looking at the IF of some downconverter
125 # that's ahead of the USRP and daughtercard. This distinction
126 # is important in computing the correct de-dispersion filter.
128 self.frequency = options.freq
129 if options.observing <= 0:
130 self.observing_freq = options.freq
132 self.observing_freq = options.observing
135 self.u = usrp.source_c(decim_rate=options.decim)
136 self.u.set_mux(usrp.determine_rx_mux_value(self.u, options.rx_subdev_spec))
139 # Recording file, in case we ever need to record baseband data
141 self.recording = gr.file_sink(gr.sizeof_char, "/dev/null")
142 self.recording_state = False
144 self.pulse_recording = gr.file_sink(gr.sizeof_short, "/dev/null")
145 self.pulse_recording_state = False
148 # We come up with recording turned off, but the user may
149 # request recording later on
150 self.recording.close()
151 self.pulse_recording.close()
154 # Need these two for converting 12-bit baseband signals to 8-bit
156 self.tofloat = gr.complex_to_float()
157 self.tochar = gr.float_to_char()
159 # Need this for recording pulses (post-detector)
160 self.toshort = gr.float_to_short()
164 # The spectral measurer sets this when it has a valid
165 # average spectral peak-to-peak distance
166 # We can then use this to program the parameters for the epoch folder
168 # We set a sentimental value here
169 self.pulse_freq = options.pulsefreq
171 # Folder runs at this raw sample rate
172 self.folder_input_rate = 20000
174 # Each pulse in the epoch folder is sampled at 128 times the nominal
180 # Try to find candidate parameters for rational resampler
184 for i in range(20,300):
185 input_rate = self.folder_input_rate
186 output_rate = int(self.pulse_freq * i)
187 interp = gru.lcm(input_rate, output_rate) / input_rate
188 decim = gru.lcm(input_rate, output_rate) / output_rate
189 if (interp < 500 and decim < 250000):
192 # We didn't find anything, bail!
193 if (len(candidates) < 1):
194 print "Couldn't converge on resampler parameters"
198 # Now try to find candidate with the least sampling error
202 diff = self.pulse_freq * i
203 diff = diff - int(diff)
209 input_rate = self.folder_input_rate
210 output_rate = int(self.pulse_freq * save_i)
212 # Compute new interp and decim, based on best candidate
213 interp = gru.lcm(input_rate, output_rate) / input_rate
214 decim = gru.lcm(input_rate, output_rate) / output_rate
216 # Save optimized folding parameters, used later
217 self.folding = save_i
218 self.interp = int(interp)
219 self.decim = int(decim)
221 # So that we can view 4 pulses in the pulse viewer window
224 # determine the daughterboard subdevice we're using
225 self.subdev = usrp.selected_subdev(self.u, options.rx_subdev_spec)
226 self.cardtype = self.u.daughterboard_id(0)
228 # Compute raw input rate
229 input_rate = self.u.adc_freq() / self.u.decim_rate()
231 # BW==input_rate for complex data
235 # Set baseband filter bandwidth if DBS_RX:
237 if self.cardtype == usrp_dbid.DBS_RX:
238 self.subdev.set_bw((self.u.adc_freq() / self.u.decim_rate())/2)
241 # We use this as a crude volume control for the audio output
243 self.volume = gr.multiply_const_ff(10**(-1))
247 # Create location data for ephem package
249 self.locality = ephem.Observer()
250 self.locality.long = str(options.longitude)
251 self.locality.lat = str(options.latitude)
254 # What is the post-detector LPF cutoff for the FFT?
256 PULSAR_MAX_FREQ=int(options.lowpass)
258 # First low-pass filters down to input_rate/FIRST_FACTOR
259 # and decimates appropriately
260 FIRST_FACTOR=int(input_rate/(self.folder_input_rate/2))
261 first_filter = gr.firdes.low_pass (1.0,
263 input_rate/FIRST_FACTOR,
264 input_rate/(FIRST_FACTOR*20),
265 gr.firdes.WIN_HAMMING)
267 # Second filter runs at the output rate of the first filter,
268 # And low-pass filters down to PULSAR_MAX_FREQ*10
270 second_input_rate = int(input_rate/(FIRST_FACTOR/2))
271 second_filter = gr.firdes.band_pass(1.0, second_input_rate,
275 gr.firdes.WIN_HAMMING)
277 # Third filter runs at PULSAR_MAX_FREQ*20
278 # and filters down to PULSAR_MAX_FREQ
280 third_input_rate = PULSAR_MAX_FREQ*20
281 third_filter = gr.firdes_band_pass(1.0, third_input_rate,
282 0.10, PULSAR_MAX_FREQ,
283 PULSAR_MAX_FREQ/10.0,
284 gr.firdes.WIN_HAMMING)
288 # Create the appropriate FFT scope
290 self.scope = ra_fftsink.ra_fft_sink_f (self, panel,
291 fft_size=int(options.fft_size), sample_rate=PULSAR_MAX_FREQ*2,
292 title="Post-detector spectrum",
293 cfunc=self.pulsarfunc, xydfunc=self.xydfunc, fft_rate=200)
296 # Tell scope we're looking from DC to PULSAR_MAX_FREQ
298 self.scope.set_baseband_freq (0.0)
302 # Setup stripchart for showing pulse profiles
304 hz = "%5.3fHz " % self.pulse_freq
305 per = "(%5.3f sec)" % (1.0/self.pulse_freq)
306 sr = "%d sps" % (int(self.pulse_freq*self.folding))
307 self.chart = ra_stripchartsink.stripchart_sink_f (self, panel,
309 stripsize=self.folding*FOLD_MULT, parallel=True, title="Pulse Profiles: "+hz+per,
310 xlabel="Seconds @ "+sr, ylabel="Level", autoscale=True,
311 divbase=self.divbase, scaling=1.0/(self.folding*self.pulse_freq))
312 self.chart.set_ref_level(self.reflevel)
313 self.chart.set_y_per_div(self.division)
315 # De-dispersion filter setup
317 # Do this here, just before creating the filter
318 # that will use the taps.
320 ntaps = self.compute_disp_ntaps(self.dm,self.bw,self.observing_freq)
322 # Taps for the de-dispersion filter
323 self.disp_taps = Numeric.zeros(ntaps,Numeric.Complex64)
325 # Compute the de-dispersion filter now
326 self.compute_dispfilter(self.dm,self.doppler,
327 self.bw,self.observing_freq)
330 # Call constructors for receive chains
334 # Now create the FFT filter using the computed taps
335 self.dispfilt = gr.fft_filter_ccc(1, self.disp_taps)
340 self.audio = audio.sink(second_input_rate, "plughw:0,0")
343 # The three post-detector filters
344 # Done this way to allow an audio path (up to 10Khz)
345 # ...and also because going from xMhz down to ~100Hz
346 # In a single filter doesn't seem to work.
348 self.first = gr.fir_filter_fff (FIRST_FACTOR/2, first_filter)
350 p = second_input_rate / (PULSAR_MAX_FREQ*20)
351 self.second = gr.fir_filter_fff (int(p), second_filter)
352 self.third = gr.fir_filter_fff (10, third_filter)
354 # Split complex USRP stream into a pair of floats
355 self.splitter = gr.complex_to_float (1);
357 # I squarer (detector)
358 self.multI = gr.multiply_ff();
360 # Q squarer (detector)
361 self.multQ = gr.multiply_ff();
363 # Adding squared I and Q to produce instantaneous signal power
364 self.adder = gr.add_ff();
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 = blks.rational_resampler_fff(self, 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, complex->float splitter
401 self.connect(self.u, self.dispfilt, self.splitter)
403 # Connect splitter outputs to multipliers
405 self.connect((self.splitter, 0), (self.multI,0))
406 self.connect((self.splitter, 0), (self.multI,1))
409 self.connect((self.splitter, 1), (self.multQ,0))
410 self.connect((self.splitter, 1), (self.multQ,1))
412 # Then sum the squares
413 self.connect(self.multI, (self.adder,0))
414 self.connect(self.multQ, (self.adder,1))
416 # Connect detector/adder output to FIR LPF
417 # in two stages, followed by the FFT scope
418 self.connect(self.adder, self.first,
419 self.second, self.third, self.scope)
421 # Connect audio output
422 self.connect(self.first, self.volume)
423 self.connect(self.volume, (self.audio, 0))
424 self.connect(self.volume, (self.audio, 1))
426 # Connect epoch folder
427 if self.enable_comb_filter == True:
428 self.connect (self.first, self.folder_bandpass, self.folder_rr,
430 self.folder_comb, self.folder_c2f,
431 self.folder_s2p, self.folder_iir,
435 self.connect (self.first, self.folder_bandpass, self.folder_rr,
436 self.folder_s2p, self.folder_iir, self.chart)
438 # Connect baseband recording file (initially /dev/null)
439 self.connect(self.u, self.tofloat, self.tochar, self.recording)
441 # Connect pulse recording file (initially /dev/null)
442 self.connect(self.first, self.toshort, self.pulse_recording)
445 # Build the GUI elements
447 self._build_gui(vbox)
449 # Make GUI agree with command-line
450 self.myform['average'].set_value(int(options.avg))
451 self.myform['foldavg'].set_value(int(options.favg))
454 # Make spectral averager agree with command line
455 if options.avg != 1.0:
456 self.scope.set_avg_alpha(float(1.0/options.avg))
457 self.scope.set_average(True)
462 if options.gain is None:
463 # if no gain was specified, use the mid-point in dB
464 g = self.subdev.gain_range()
465 options.gain = float(g[0]+g[1])/2
467 if options.freq is None:
468 # if no freq was specified, use the mid-point
469 r = self.subdev.freq_range()
470 options.freq = float(r[0]+r[1])/2
472 self.set_gain(options.gain)
473 self.set_volume(-10.0)
475 if not(self.set_freq(options.freq)):
476 self._set_status_msg("Failed to set initial frequency")
478 self.myform['decim'].set_value(self.u.decim_rate())
479 self.myform['fs@usb'].set_value(self.u.adc_freq() / self.u.decim_rate())
480 self.myform['dbname'].set_value(self.subdev.name())
481 self.myform['DM'].set_value(self.dm)
482 self.myform['Doppler'].set_value(self.doppler)
485 # Start the timer that shows current LMST on the GUI
487 self.lmst_timer.Start(1000)
490 def _set_status_msg(self, msg):
491 self.frame.GetStatusBar().SetStatusText(msg, 0)
493 def _build_gui(self, vbox):
495 def _form_set_freq(kv):
496 return self.set_freq(kv['freq'])
498 def _form_set_dm(kv):
499 return self.set_dm(kv['DM'])
501 def _form_set_doppler(kv):
502 return self.set_doppler(kv['Doppler'])
504 # Position the FFT or Waterfall
505 vbox.Add(self.scope.win, 5, wx.EXPAND)
506 vbox.Add(self.chart.win, 5, wx.EXPAND)
508 # add control area at the bottom
509 self.myform = myform = form.form()
510 hbox = wx.BoxSizer(wx.HORIZONTAL)
511 hbox.Add((7,0), 0, wx.EXPAND)
512 vbox1 = wx.BoxSizer(wx.VERTICAL)
513 myform['freq'] = form.float_field(
514 parent=self.panel, sizer=vbox1, label="Center freq", weight=1,
515 callback=myform.check_input_and_call(_form_set_freq, self._set_status_msg))
517 vbox1.Add((3,0), 0, 0)
519 # To show current Local Mean Sidereal Time
520 myform['lmst_high'] = form.static_text_field(
521 parent=self.panel, sizer=vbox1, label="Current LMST", weight=1)
522 vbox1.Add((3,0), 0, 0)
524 # To show current spectral cursor data
525 myform['spec_data'] = form.static_text_field(
526 parent=self.panel, sizer=vbox1, label="Pulse Freq", weight=1)
527 vbox1.Add((3,0), 0, 0)
529 # To show best pulses found in FFT output
530 myform['best_pulse'] = form.static_text_field(
531 parent=self.panel, sizer=vbox1, label="Best freq", weight=1)
532 vbox1.Add((3,0), 0, 0)
534 vboxBogus = wx.BoxSizer(wx.VERTICAL)
535 vboxBogus.Add ((2,0), 0, wx.EXPAND)
536 vbox2 = wx.BoxSizer(wx.VERTICAL)
537 g = self.subdev.gain_range()
538 myform['gain'] = form.slider_field(parent=self.panel, sizer=vbox2, label="RF Gain",
540 min=int(g[0]), max=int(g[1]),
541 callback=self.set_gain)
543 vbox2.Add((6,0), 0, 0)
544 myform['average'] = form.slider_field(parent=self.panel, sizer=vbox2,
545 label="Spectral Averaging", weight=1, min=1, max=200, callback=self.set_averaging)
546 vbox2.Add((6,0), 0, 0)
547 myform['foldavg'] = form.slider_field(parent=self.panel, sizer=vbox2,
548 label="Folder Averaging", weight=1, min=1, max=20, callback=self.set_folder_averaging)
549 vbox2.Add((6,0), 0, 0)
550 myform['volume'] = form.quantized_slider_field(parent=self.panel, sizer=vbox2,
551 label="Audio Volume", weight=1, range=(-20, 0, 0.5), callback=self.set_volume)
552 vbox2.Add((6,0), 0, 0)
553 myform['DM'] = form.float_field(
554 parent=self.panel, sizer=vbox2, label="DM", weight=1,
555 callback=myform.check_input_and_call(_form_set_dm))
556 vbox2.Add((6,0), 0, 0)
557 myform['Doppler'] = form.float_field(
558 parent=self.panel, sizer=vbox2, label="Doppler", weight=1,
559 callback=myform.check_input_and_call(_form_set_doppler))
560 vbox2.Add((6,0), 0, 0)
563 # Baseband recording control
564 buttonbox = wx.BoxSizer(wx.HORIZONTAL)
565 self.record_control = form.button_with_callback(self.panel,
566 label="Recording baseband: Off ",
567 callback=self.toggle_recording)
568 self.record_pulse_control = form.button_with_callback(self.panel,
569 label="Recording pulses: Off ",
570 callback=self.toggle_pulse_recording)
572 buttonbox.Add(self.record_control, 0, wx.CENTER)
573 buttonbox.Add(self.record_pulse_control, 0, wx.CENTER)
574 vbox.Add(buttonbox, 0, wx.CENTER)
575 hbox.Add(vbox1, 0, 0)
576 hbox.Add(vboxBogus, 0, 0)
577 hbox.Add(vbox2, wx.ALIGN_RIGHT, 0)
578 vbox.Add(hbox, 0, wx.EXPAND)
580 self._build_subpanel(vbox)
582 self.lmst_timer = wx.PyTimer(self.lmst_timeout)
586 def _build_subpanel(self, vbox_arg):
587 # build a secondary information panel (sometimes hidden)
589 # FIXME figure out how to have this be a subpanel that is always
590 # created, but has its visibility controlled by foo.Show(True/False)
592 if not(self.show_debug_info):
599 #panel = wx.Panel(self.panel, -1)
600 #vbox = wx.BoxSizer(wx.VERTICAL)
602 hbox = wx.BoxSizer(wx.HORIZONTAL)
604 myform['decim'] = form.static_float_field(
605 parent=panel, sizer=hbox, label="Decim")
608 myform['fs@usb'] = form.static_float_field(
609 parent=panel, sizer=hbox, label="Fs@USB")
612 myform['dbname'] = form.static_text_field(
613 parent=panel, sizer=hbox)
616 myform['baseband'] = form.static_float_field(
617 parent=panel, sizer=hbox, label="Analog BB")
620 myform['ddc'] = form.static_float_field(
621 parent=panel, sizer=hbox, label="DDC")
624 vbox.Add(hbox, 0, wx.EXPAND)
628 def set_freq(self, target_freq):
630 Set the center frequency we're interested in.
632 @param target_freq: frequency in Hz
635 Tuning is a two step process. First we ask the front-end to
636 tune as close to the desired frequency as it can. Then we use
637 the result of that operation and our target_frequency to
638 determine the value for the digital down converter.
640 r = usrp.tune(self.u, 0, self.subdev, target_freq)
643 self.myform['freq'].set_value(target_freq) # update displayed value
644 self.myform['baseband'].set_value(r.baseband_freq)
645 self.myform['ddc'].set_value(r.dxc_freq)
646 # Adjust self.frequency, and self.observing_freq
647 # We pick up the difference between the current self.frequency
648 # and the just-programmed one, and use this to adjust
649 # self.observing_freq. We have to do it this way to
650 # make the dedispersion filtering work out properly.
651 delta = target_freq - self.frequency
652 self.frequency = target_freq
653 self.observing_freq += delta
655 # Now that we're adjusted, compute a new dispfilter, and
656 # set the taps for the FFT filter.
657 ntaps = self.compute_disp_ntaps(self.dm, self.bw, self.observing_freq)
658 self.disp_taps = Numeric.zeros(ntaps, Numeric.Complex64)
659 self.compute_dispfilter(self.dm,self.doppler,self.bw,
661 self.dispfilt.set_taps(self.disp_taps)
667 # Callback for gain-setting slider
668 def set_gain(self, gain):
669 self.myform['gain'].set_value(gain) # update displayed value
670 self.subdev.set_gain(gain)
673 def set_volume(self, vol):
674 self.myform['volume'].set_value(vol)
675 self.volume.set_k((10**(vol/10))/8192)
677 # Callback for spectral-averaging slider
678 def set_averaging(self, avval):
679 self.myform['average'].set_value(avval)
680 self.scope.set_avg_alpha(1.0/(avval))
681 self.scope.set_average(True)
683 def set_folder_averaging(self, avval):
684 self.myform['foldavg'].set_value(avval)
685 self.folder_iir.set_taps(1.0/avval)
687 # Timer callback to update LMST display
688 def lmst_timeout(self):
689 self.locality.date = ephem.now()
690 sidtime = self.locality.sidereal_time()
691 self.myform['lmst_high'].set_value(str(ephem.hours(sidtime)))
694 # Turn recording on/off
695 # Called-back by "Recording" button
697 def toggle_recording(self):
698 # Pick up current LMST
699 self.locality.date = ephem.now()
700 sidtime = self.locality.sidereal_time()
702 # Pick up localtime, for generating filenames
703 foo = time.localtime()
705 # Generate filenames for both data and header file
706 filename = "%04d%02d%02d%02d%02d.pdat" % (foo.tm_year, foo.tm_mon,
707 foo.tm_mday, foo.tm_hour, foo.tm_min)
708 hdrfilename = "%04d%02d%02d%02d%02d.phdr" % (foo.tm_year, foo.tm_mon,
709 foo.tm_mday, foo.tm_hour, foo.tm_min)
711 # Current recording? Flip state
712 if (self.recording_state == True):
713 self.recording_state = False
714 self.record_control.SetLabel("Recording baseband: Off ")
715 self.recording.close()
718 self.recording_state = True
719 self.record_control.SetLabel("Recording baseband to: "+filename)
721 # Cause gr_file_sink object to accept new filename
722 # note use of self.prefix--filename prefix from
723 # command line (defaults to ./)
725 self.recording.open (self.prefix+filename)
728 # We open the header file as a regular file, write header data,
730 hdrf = open(self.prefix+hdrfilename, "w")
731 hdrf.write("receiver center frequency: "+str(self.frequency)+"\n")
732 hdrf.write("observing frequency: "+str(self.observing_freq)+"\n")
733 hdrf.write("DM: "+str(self.dm)+"\n")
734 hdrf.write("doppler: "+str(self.doppler)+"\n")
736 hdrf.write("sidereal: "+str(ephem.hours(sidtime))+"\n")
737 hdrf.write("bandwidth: "+str(self.u.adc_freq() / self.u.decim_rate())+"\n")
738 hdrf.write("sample type: complex_char\n")
739 hdrf.write("sample size: "+str(gr.sizeof_char*2)+"\n")
742 # Turn recording on/off
743 # Called-back by "Recording" button
745 def toggle_pulse_recording(self):
746 # Pick up current LMST
747 self.locality.date = ephem.now()
748 sidtime = self.locality.sidereal_time()
750 # Pick up localtime, for generating filenames
751 foo = time.localtime()
753 # Generate filenames for both data and header file
754 filename = "%04d%02d%02d%02d%02d.padat" % (foo.tm_year, foo.tm_mon,
755 foo.tm_mday, foo.tm_hour, foo.tm_min)
756 hdrfilename = "%04d%02d%02d%02d%02d.pahdr" % (foo.tm_year, foo.tm_mon,
757 foo.tm_mday, foo.tm_hour, foo.tm_min)
759 # Current recording? Flip state
760 if (self.pulse_recording_state == True):
761 self.pulse_recording_state = False
762 self.record_pulse_control.SetLabel("Recording pulses: Off ")
763 self.pulse_recording.close()
766 self.pulse_recording_state = True
767 self.record_pulse_control.SetLabel("Recording pulses to: "+filename)
769 # Cause gr_file_sink object to accept new filename
770 # note use of self.prefix--filename prefix from
771 # command line (defaults to ./)
773 self.pulse_recording.open (self.prefix+filename)
776 # We open the header file as a regular file, write header data,
778 hdrf = open(self.prefix+hdrfilename, "w")
779 hdrf.write("receiver center frequency: "+str(self.frequency)+"\n")
780 hdrf.write("observing frequency: "+str(self.observing_freq)+"\n")
781 hdrf.write("DM: "+str(self.dm)+"\n")
782 hdrf.write("doppler: "+str(self.doppler)+"\n")
783 hdrf.write("pulse rate: "+str(self.pulse_freq)+"\n")
784 hdrf.write("pulse sps: "+str(self.pulse_freq*self.folding)+"\n")
785 hdrf.write("file sps: "+str(self.folder_input_rate)+"\n")
787 hdrf.write("sidereal: "+str(ephem.hours(sidtime))+"\n")
788 hdrf.write("bandwidth: "+str(self.u.adc_freq() / self.u.decim_rate())+"\n")
789 hdrf.write("sample type: short\n")
790 hdrf.write("sample size: 1\n")
793 # We get called at startup, and whenever the GUI "Set Folding params"
796 def set_folding_params(self):
797 if (self.pulse_freq <= 0):
800 # Compute required sample rate
801 self.sample_rate = int(self.pulse_freq*self.folding)
803 # And the implied decimation rate
804 required_decimation = int(self.folder_input_rate / self.sample_rate)
806 # We also compute a new FFT comb filter, based on the expected
807 # spectral profile of our pulse parameters
809 # FFT-based comb filter
811 N_COMB_TAPS=int(self.sample_rate*4)
812 if N_COMB_TAPS > 2000:
814 self.folder_comb_taps = Numeric.zeros(N_COMB_TAPS,Numeric.Complex64)
815 fincr = (self.sample_rate)/float(N_COMB_TAPS)
816 for i in range(0,len(self.folder_comb_taps)):
817 self.folder_comb_taps[i] = complex(0.0, 0.0)
820 harmonics = [1.0,2.0,3.0,4.0,5.0,6.0,7.0]
821 for i in range(0,len(self.folder_comb_taps)/2):
822 for j in range(0,len(harmonics)):
823 if abs(freq - harmonics[j]*self.pulse_freq) <= fincr:
824 self.folder_comb_taps[i] = complex(4.0, 0.0)
825 if harmonics[j] == 1.0:
826 self.folder_comb_taps[i] = complex(8.0, 0.0)
829 if self.enable_comb_filter == True:
830 # Set the just-computed FFT comb filter taps
831 self.folder_comb.set_taps(self.folder_comb_taps)
833 # And compute a new decimated bandpass filter, to go in front
834 # of the comb. Primary function is to decimate and filter down
835 # to an exact-ish multiple of the target pulse rate
837 self.folding_taps = gr.firdes_band_pass (1.0, self.folder_input_rate,
838 0.10, self.sample_rate/2, 10,
839 gr.firdes.WIN_HAMMING)
841 # Set the computed taps for the bandpass/decimate filter
842 self.folder_bandpass.set_taps (self.folding_taps)
844 # Record a spectral "hit" of a possible pulsar spectral profile
846 def record_hit(self,hits, hcavg, hcmax):
847 # Pick up current LMST
848 self.locality.date = ephem.now()
849 sidtime = self.locality.sidereal_time()
851 # Pick up localtime, for generating filenames
852 foo = time.localtime()
854 # Generate filenames for both data and header file
855 hitfilename = "%04d%02d%02d%02d.phit" % (foo.tm_year, foo.tm_mon,
856 foo.tm_mday, foo.tm_hour)
858 hitf = open(self.prefix+hitfilename, "a")
859 hitf.write("receiver center frequency: "+str(self.frequency)+"\n")
860 hitf.write("observing frequency: "+str(self.observing_freq)+"\n")
861 hitf.write("DM: "+str(self.dm)+"\n")
862 hitf.write("doppler: "+str(self.doppler)+"\n")
864 hitf.write("sidereal: "+str(ephem.hours(sidtime))+"\n")
865 hitf.write("bandwidth: "+str(self.u.adc_freq() / self.u.decim_rate())+"\n")
866 hitf.write("spectral peaks: "+str(hits)+"\n")
867 hitf.write("HCM: "+str(hcavg)+" "+str(hcmax)+"\n")
870 # This is a callback used by ra_fftsink.py (passed on creation of
872 # Whenever the user moves the cursor within the FFT display, this
873 # shows the coordinate data
875 def xydfunc(self,xyv):
876 s = "%.6fHz\n%.3fdB" % (xyv[0], xyv[1])
877 if self.lowpass >= 500:
878 s = "%.6fHz\n%.3fdB" % (xyv[0]*1000, xyv[1])
880 self.myform['spec_data'].set_value(s)
882 # This is another callback used by ra_fftsink.py (passed on creation
883 # of ra_fftsink). We pass this as our "calibrator" function, but
884 # we create interesting side-effects in the GUI.
886 # This function finds peaks in the FFT output data, and reports
887 # on them through the "Best" text object in the GUI
888 # It also computes the Harmonic Compliance Measure (HCM), and displays
891 def pulsarfunc(self,d,l):
893 incr = float(self.lowpass)/float(l)
900 # First, we need to find the average signal level
903 if (i * incr) > self.lowest_freq and (i*incr) < (self.lowpass-2):
906 # Set average signal level
911 # Then we find candidates that are greater than the user-supplied
914 # We try to cluster "hits" whose whole-number frequency is the
915 # same, and compute an average "hit" frequency.
923 # If frequency within bounds, and the (dB-avg) value is above our
925 if freq > self.lowest_freq and freq < self.lowpass-2 and (d[i] - avg) > self.threshold:
926 # If we're finding a new whole-number frequency
927 if lastint != int(freq):
928 # Record "center" of this hit, if this is a new hit
930 s2 += "%5.3fHz " % (freqavg/intcnt)
931 hits.append(freqavg/intcnt)
943 s2 += "%5.3fHz " % (freqavg/intcnt)
944 hits.append(freqavg/intcnt)
947 # Compute the HCM, by dividing each of the "hits" by each of the
948 # other hits, and comparing the difference between a "perfect"
949 # harmonic, and the observed frequency ratio.
956 for i in range(1,len(hits)):
957 meas = hits[i]/hits[0] - int(hits[i]/hits[0])
958 if abs((hits[i]-hits[i-1])-hits[0]) < 0.1:
959 avg_dist += hits[i]-hits[i-1]
961 if meas > 0.98 and meas < 1.0:
964 if meas >= max_measure:
974 s3="\nHCM: Avg %5.3fHz(%d) Max %5.3fHz Dist %5.3fHz(%d)" % (measure,mcnt,max_measure, avg_dist, acnt)
975 if max_measure < 0.5 and len(hits) >= 2:
976 self.record_hit(hits, measure, max_measure)
977 self.avg_dist = avg_dist
980 s4="\nAvg dB: %4.2f" % avg
981 self.myform['best_pulse'].set_value("("+s2+")"+s3+s4)
983 # Since we are nominally a calibrator function for ra_fftsink, we
984 # simply return what they sent us, untouched. A "real" calibrator
985 # function could monkey with the data before returning it to the
986 # FFT display function.
990 # Callback for the "DM" gui object
992 # We call compute_dispfilter() as appropriate to compute a new filter,
993 # and then set that new filter into self.dispfilt.
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['DM'].set_value(dm)
1006 # Callback for the "Doppler" gui object
1008 # We call compute_dispfilter() as appropriate to compute a new filter,
1009 # and then set that new filter into self.dispfilt.
1011 def set_doppler(self,doppler):
1012 self.doppler = doppler
1014 ntaps = self.compute_disp_ntaps (self.dm, self.bw, self.observing_freq)
1015 self.disp_taps = Numeric.zeros(ntaps, Numeric.Complex64)
1016 self.compute_dispfilter(self.dm,self.doppler,self.bw,self.observing_freq)
1017 self.dispfilt.set_taps(self.disp_taps)
1018 self.myform['Doppler'].set_value(doppler)
1022 # Compute a de-dispersion filter
1023 # From Hankins, et al, 1975
1025 # This code translated from dedisp_filter.c from Swinburne
1026 # pulsar software repository
1028 def compute_dispfilter(self,dm,doppler,bw,centerfreq):
1029 npts = len(self.disp_taps)
1030 tmp = Numeric.zeros(npts, Numeric.Complex64)
1031 M_PI = 3.14159265358
1035 # Because astronomers are a crazy bunch, the "standard" calcultion
1036 # is in Mhz, rather than Hz
1038 centerfreq = centerfreq / 1.0e6
1041 isign = int(bw / abs (bw))
1043 # Center frequency may be doppler shifted
1044 cfreq = centerfreq / doppler
1046 # As well as the bandwidth..
1047 bandwidth = bw / doppler
1049 # Bandwidth divided among bins
1050 binwidth = bandwidth / npts
1052 # Delay is an "extra" parameter, in usecs, and largely
1053 # untested in the Swinburne code.
1056 # This determines the coefficient of the frequency response curve
1057 # Linear in DM, but quadratic in center frequency
1058 coeff = isign * 2.0*M_PI * DM / (cfreq*cfreq)
1062 for i in range(0,int(npts/2)):
1063 freq = (n + 0.5) * binwidth
1064 phi = coeff*freq*freq/(cfreq+freq) + (2.0*M_PI*freq*delay)
1065 tmp[i] = complex(math.cos(phi), math.sin(phi))
1071 for i in range(int(npts/2),npts):
1072 freq = (n + 0.5) * binwidth
1073 phi = coeff*freq*freq/(cfreq+freq) + (2.0*M_PI*freq*delay)
1074 tmp[i] = complex(math.cos(phi), math.sin(phi))
1077 self.disp_taps = FFT.inverse_fft(tmp)
1078 return(self.disp_taps)
1081 # Compute minimum number of taps required in de-dispersion FFT filter
1083 def compute_disp_ntaps(self,dm,bw,freq):
1085 # Dt calculations are in Mhz, rather than Hz
1086 # crazy astronomers....
1090 f_lower = mfreq-(mbw/2)
1091 f_upper = mfreq+(mbw/2)
1093 # Compute smear time
1094 Dt = dm/2.41e-4 * (1.0/(f_lower*f_lower)-1.0/(f_upper*f_upper))
1096 # ntaps is now bandwidth*smeartime
1097 # Should be bandwidth*smeartime*2, but the Gnu Radio FFT filter
1098 # already expands it by a factor of 2
1105 app = stdgui.stdapp(app_flow_graph, "RADIO ASTRONOMY PULSAR RECEIVER: $Revision$", nstatus=1)
1108 if __name__ == '__main__':