; BPCOR ;--------------------------------------------------------------- ;! Correct BP table. ;# Task Calibration ;----------------------------------------------------------------------- ;; Copyright (C) 1995-1996, 2008 ;; Associated Universities, Inc. Washington DC, USA. ;; ;; This program is free software; you can redistribute it and/or ;; modify it under the terms of the GNU General Public License as ;; published by the Free Software Foundation; either version 2 of ;; the License, or (at your option) any later version. ;; ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; ;; You should have received a copy of the GNU General Public ;; License along with this program; if not, write to the Free ;; Software Foundation, Inc., 675 Massachusetts Ave, Cambridge, ;; MA 02139, USA. ;; ;; Correspondence concerning AIPS should be addressed as follows: ;; Internet email: aipsmail@nrao.edu. ;; Postal address: AIPS Project Office ;; National Radio Astronomy Observatory ;; 520 Edgemont Road ;; Charlottesville, VA 22903-2475 USA ;----------------------------------------------------------------------- BPCOR LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC BPCOR Task to apply various corrections to BP spectra. INNAME Input UV file name (name) INCLASS Input UV file name (class) INSEQ 0.0 9999.0 Input UV file name (seq. #) INDISK 0.0 9.0 Input UV file disk unit # SOURCES Source list ' '=>all. STOKES Stokes type to process FREQID -1.0 9999.0 Freq. ID to select, 0=>all BIF 0.0 100.0 Lowest IF number 0=>all EIF 0.0 100.0 Highest IF number 0=>all TIMERANG Time range to use. ANTENNAS Antennas to correct. SUBARRAY 0.0 9999.0 Subarray; 0 => 1. BPVER 1.0 9999.0 Input BP table version (will append new table) CODETYPE Components to smooth 'R&I', 'A&P','A','P',' ' => 'R&I' Not used for OPCODE='SPEC' OPCODE Correction mode: 'FUNC' => scale by function 'HANN' => Hanning smooth 'BOXC' => Boxcar smooth 'GAUS' => Guassian smooth 'SINC' => Sinc smooth 'BMED' => Broadened median filter 'SPEC' => spectral index correction ' ' => pass BP table obeying BPARMS APARM Parameters (see HELP BPCOR). For smoothing then: APARM(1) = smoothing function diameter (channels) HANN, BOXC - full diam GAUS - FWHM SINC - first nulls BMED - median window diam APARM(2) = smoothing support func diameter in chans. For spectral index (SPEC) APARM(1) = spectral index APARM(2) = start channel APARM(3) = end channel APARM(4) = channel about which spectrum will pivot For interpolation (POLY) APARM(1) = polyn. order to fit to amplitude APARM(2) = polyn. order to fit to phase BPARM Parameters (see HELP BPCOR) (1) 1=> set phase to zero (2) 0=> normalise BP ampl CPARM Channels to fit (OPCODE = 'POLY' only) Pairs of starting, ending channels to use in the fit CALIN Text file for FUNC mode BADDISK 0.0 9999.0 Disks to aviod for scratch ---------------------------------------------------------------- BPCOR Task: Task to correct bandpass correction tables. Use: BPCOR applies various smoothing and other correction methods to the selected data in the input BP table. All other data in the table are copied to the output table unmodified. The output BP table is always version number one higher than the previous highest number. FUNCTION: The calibration source may not have a frequency-independent flux because of, for example, absorption due to hydrogen in the Galaxy. The FUNC mode may be used to correct the amplitude of the BP for an arbitrary spectral shape. The user provides the shape, listing the channels to be corrected and their correction factors in a text file. SMOOTHING: The principal correction mode is smoothing: several smoothing methods are available including Hanning, Gaussian, Boxcar and Sinc smoothing. Broadened median window filtering is also possible. SPECTRAL INDEX CORRECTION: The BP spectra can also be corrected for the effects of a spectral index across the band. INTERPOLATION: The BP spectra can also be interpolated with a polynomial (OPCODE = 'POLY') NOT IMPLEMENTED!! The corrected complex bandpasses can be normalised before output and the phase response can be set to zero if desired. Adverbs: INNAME.....Input UV file name (name). Standard defaults. INCLASS....Input UV file name (class). Standard defaults. INSEQ......Input UV file name (seq. #). 0 => highest. INDISK.....Disk drive # of input UV file. 0 => any. SOURCES....list of sources to process. '*' = all; a "-" before a source name means all except ANY source named. STOKES.....The desired Stokes type to select: 'R ', 'L ', 'RL', ' '=> 'RL'. FREQID.....Frequency identifier to select (you may determine which is applicable from the OPTYPE='SCAN' listing produced by LISTR). BIF........First IF to process. 0=>all. EIF........Highest IF to process. 0=>all higher than BIF TIMERANG...Time range of the data to be used. In order: Start day, hour, min. sec, end day, hour, min. sec. Days relative to ref. date. ANTENNAS...A list of the antennas to be modified. If any number is negative then all antennas listed are NOT to be modified. All 0 => use all. SUBARRAY...The subarray to modify. Do only one at a time. BPVER......The input BP table version number. NOTE: There is NO default value. The output BP table will always be version 0 (i.e. appended after the last existing BP table). CODETYPE...Which components are to be smoothed. 'R&I'=> real and imag; 'A&P'=> ampl and phase, ' '=> 'R&I' 'A ' or 'P ' - used for opcode 'POLY' only This parameter is ignored for OPCODE = 'SPEC' OPCODE.....Type of correction to be performed: 'FUNC' - input gain function 'HANN' - Hanning smoothing 'BOXC' - Boxcar smoothing 'GAUS' - Gaussian smoothing 'SINC' - Sin x/x smoothing. 'BMED' - Broadened median window filtering. 'SPEC' - Spectral index correction. 'POLY' - polynomial interpolation - NOT IMPLEMENTED APARM......Smoothing parameters: APARM(1) = Smoothing function diameter (chan) 'HANN','BOXC' - full width. 'GAUS' - FWHM 'SINC' - width between first nulls. 'BMED' - median window diameter. 'SPEC' - spectral index present in the data, defined as S = So * freq ** alpha. This spectral index will be removed from the data. 'POLY' - order of polynomial to fit to amplitude APARM(2) = Smoothing function support (chan) (not required for OPCODE='BMED'). 'SPEC' - start channel for spectral index correction. 'POLY' - order of polynomial to fit to phase APARM(3) 'SPEC' - stop channel for spectral index correction. APARM(4) 'SPEC' - channel about which the the spectrum will pivot. If zero will be the central channel. BPARM......Options after correction is completed. BPARM(1): 0=> phase unchanged; 1=> set phase to zero across the band; BPARM(2): 0=> normalise the bandpass amplitude; 1=> bandpass amplitude unchanged; CPARM......Channel to use in the interpolation. (OPCODE = 'POLY' only) CPARM(1): starting channel for window 1 CPARM(2): last channel for window 1 etc. for a total of 5 windows CALIN......Name for input text file used in the FUNC mode. e.g. CALIN='MYAREA:MYFILE.TXT'. Each line of the file is used to give the correction factor (actually divisor) for one channel. Thus, a weak absorption feature would be corrected with 63 0.999 64 0.995 65 0.990 66 0.988 67 0.991 68 0.996 where channels 1-62 and 69-n have no correction applied. Blank lines or ones beggining with a $ or an * are ignored. Others may cause problems. BADDISK....A list of disks on which scratch files are not to be placed. This will not affect the output file. ----------------------------------------------------------------