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Updated backend delays for VEGAS #5

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Updated backend delays for VEGAS #5

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3 changes: 3 additions & 0 deletions config/update_be_delay.psrsh
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Original file line number Diff line number Diff line change
Expand Up @@ -2,3 +2,6 @@ if ($be:name==GUPPI && $ext:obsnchan==576) e ext:obsnchan=512
if ($be:name==GUPPI && $ext:obsnchan==144) e ext:obsnchan=128
if (($be:name==GUPPI || $be:name==PUPPI) && fabs($ext:obsbw/$ext:obsnchan)==1.5625) e be:delay=3.84e-6
if ($be:name==GUPPI && $ext:obsnchan==128 && $ext:stt_imjd<55692 && $ext:stt_imjd>55587 && fabs($ext:obsbw)==200) e be:delay=2.56e-6
if ($be:name==VEGAS && ($ext:stt_imjd+$ext:stt_smjd/86400.0)<59045.775) e rcvr:hand=1,be:phase=1
if ($be:name==VEGAS && $nchan==128 && $bw==-200 && $ext:stt_imjd<58991) e ext:obsnchan=128,ext:obsbw=-200
if (($be:name==VEGAS) && fabs($ext:obsbw/$ext:obsnchan)==1.5625) e be:delay=-7.43e-6
78 changes: 53 additions & 25 deletions scripts/update_be_delay
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Original file line number Diff line number Diff line change
Expand Up @@ -58,7 +58,7 @@ mode = opt.mode
for fname in args:
f = fitsio.FITS(fname,'rw')
h = f[0].read_header()
if not 'UPPI' in h['BACKEND']:
if not ('UPPI' in h['BACKEND'] or h['BACKEND'] == 'VEGAS'):
print "%s: backend='%s', skipping" % (fname, h['BACKEND'])
f.close()
continue
Expand Down Expand Up @@ -110,33 +110,61 @@ for fname in args:
else:
# All coherent data should be AABBCRCI or IQUV
mode = "csearch" if dt > 5e-6 else "cfold"
if 'UPPI' in h['BACKEND']:
pfb_fac = 2.0
if (mode=="csearch" or mode=="cfold"):
if (nchan==2048):
pfb_fac = 2.0
elif ((nchan==128) and (h['STT_IMJD']<55692 and
h['STT_IMJD']>55587)):
pfb_fac = 4.0
else:
pfb_fac = 6.0
be_delay = pfb_fac / orig_ch_bw # pfb corr in us. All modes get this

# For coherent search modes, you need to add 1/2 chirp overlap
if mode=='csearch':
try:
dm = float(h['CHAN_DM'])
# Overlap is returned in number of single-channel samples
fftlen, overlap, blocsize = fft_size_params(rf,bw,nchan,dm)
# Covert it to us
overlap_us = float(overlap) / orig_ch_bw
# Add it to pfb delay
be_delay += 0.5 * overlap_us
except ValueError: # Can't convert dm to float, likely.
pass
elif h['BACKEND'] == "VEGAS":
# Corrections for VEGAS 100 and 200 MHz bandwidth modes
# These modes use a native sampled 800 MHz BW but only return
# nchan/8 or nchan/4 of the total number of channels
clock_rate = 100 if bw in (100,200) else bw/8
hw_nchan = int(nchan*800/bw) if bw in (100,200) else nchan

pfb_fac = 2.0
if (mode=="csearch" or mode=="cfold"):
if (nchan==2048):
pfb_fac = 2.0
elif ((nchan==128) and (h['STT_IMJD']<55692 and
h['STT_IMJD']>55587)):
pfb_fac = 4.0
# Number of taps provided by Jason Ray ([email protected]). Most
# designs use 24.
if (mode == "cfold" or mode == "csearch") and hw_nchan == 1024:
ntaps = 12 # CODD 1024-channel modes use 12 taps for all bandwidths
elif mode == "incoh" and bw == 100:
if hw_nchan == 65536:
ntaps = 4
elif hw_nchan == 32768 or hw_nchan == 16384:
ntaps = 12
else:
ntaps = 24
elif mode == "incoh" and bw == 200:
ntaps = 12
else:
pfb_fac = 6.0
be_delay = pfb_fac / orig_ch_bw # pfb corr in us. All modes get this

# For coherent search modes, you need to add 1/2 chirp overlap
if mode=='csearch':
try:
dm = float(h['CHAN_DM'])
# Overlap is returned in number of single-channel samples
fftlen, overlap, blocsize = fft_size_params(rf, bw, nchan, dm)
# Covert it to us
overlap_us = float(overlap) / orig_ch_bw
# Add it to pfb delay
be_delay += 0.5 * overlap_us
except ValueError: # Can't convert dm to float, likely.
pass

ntaps = 24

# Clock rate should be in MHz
# VEGAS PFB delays are opposite sign from GUPPI because of different
# behavior when the sync pulse hits the PFB
# This formula was provided by Luke Hawkins and was determined
# via manual inspection of the structure of the VEGAS PFBs
be_delay = -0.5*((ntaps-1)*(2**(np.log2(nchan)-3))+14)/clock_rate

be_delay = be_delay * 1e-6 if opt.value is None else opt.value
print "%s: %s %.12g %d %.5e" % (fname, mode, rf, nchan, be_delay)
f[0].write_key('BE_DELAY', be_delay, '[s] Updated')
f.close()