; SPLAT ;--------------------------------------------------------------- ;! Applies calibration and splits or assemble selected sources. ;# Task UV Calibration ;----------------------------------------------------------------------- ;; Copyright (C) 1995-2000, 2004, 2006 ;; 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 ;----------------------------------------------------------------------- SPLAT LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC SPLAT Split/assemble the sources in single/multi source file 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 QUAL -1.0 Source qualifier -1=>all CALCODE Calibrator code ' '=>all TIMERANG Time range to copy STOKES Stokes type to pass. Look HELP. SELBAND Bandwidth to select (kHz) SELFREQ Frequency to select (MHz) FREQID Freq. ID to select. BIF 0.0 100.0 Lowest IF number 0=>all EIF 0.0 100.0 Highest IF number 0=>all BCHAN 0.0 2048.0 Lowest channel number 0=>all ECHAN 0.0 2048.0 Highest channel number SUBARRAY 0.0 1000.0 Subarray, 0=>all DOCALIB -1.0 101.0 > 0 calibrate data & weights > 99 do NOT calibrate weights GAINUSE CL (or SN) table to apply DOPOL -1.0 10.0 If >0 correct polarization. BLVER BL table to apply. FLAGVER Flag table version. 0 => highest numbered table <0 => no flagging DOBAND -1.0 10.0 If >0 apply bandpass cal. Method used depends on value of DOBAND (see HELP file). BPVER Bandpass table version SMOOTH Smoothing function. See HELP SMOOTH for details. OUTNAME Output UV file name (name) OUTCLASS Output UV file name (class) OUTSEQ -1.0 9999.0 Output UV file name (seq. #) OUTDISK 0.0 9.0 Output UV file disk unit #. DOUVCOMP -1.0 1.0 1 (T) => compressed data APARM Control information: 1 = 1 => avg. freq. in IF Use ICHANSEL. CHANNEL is not used = 2 => avg IF's also Use ICHANSEL. CHANNEL is not used = 3 => average each CHANNEL channels. ICHANSEL is not used. 2 = Input avg. time (sec) 3 > 0 => Drop subarrays 5 = 0 pass only xc data = 1 pass xc and ac data = 2 pass only ac data 6 > 0 add full source name to header 7 = 0 assemble all selected sources in one multiple source file. > 0 split for single source files. ICHANSEL Array of channel start, stop, and increment numbers and IF number to be used when averaging in frequency. It's used if APARM(1)=1 or 2 CHANNEL Number of chans to average together; if APARM(1) = 3 CHINC Increment in input chans for output 0 -> CHANNEL; if APARM(1) = 3 SOLINT Time of averaging in min. 0 => no averaging BADDISK 0.0 9999.0 Disks to avoid for scratch ---------------------------------------------------------------- SPLAT Task: Split a multi source uv data set into single source data or assemble the selected sources into new multi source file having applied calibration and averaging data in time and in frequency. Multiple sources may be processed in a single run. Calibration and editing may be optionally applied. Fully flagged data will not be copied. SPLAT will also apply an unapplied SN table to a single-source file. This may be done by copying an appropriate SN table to the input file. A warning message may appear if the SN table had previously been applied to any dataset. SPLAT differs from SPLIT in that it can write a multi-source output file and that it will copy calibration tables unless they were applied. If a BP table is applied, no BP table is copied. If DOCAL is true, no CL, SN, TY, or GC table is copied. If an FG table is applied, no FG table is copied. SPLIT copies no calibration tables under all circumstances. 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....Source list. '*' = all; a "-" before a source name means all except ANY source named. In the split option separate single source file is created for each selected source. QUAL.......Only sources with a source qualifier number in the SU table matching QUAL will be used if QUAL is >= 0. If QUAL < 0, all qualifiers will be written. These qualifiers will be written to separate output files. Note that OUTSEQ must be zero in this case. CALCODE....Sources may be selected on the basis of the calibrator code given in the SU table. ' ' => any calibrator code selected '* ' => any non blank code (cal. only) '-CAL' => blank codes only (no calibrators) anything else = calibrator code to select. NB: The CALCODE test is applied in addition to the other tests, i.e. SOURCS and QUAL, in the selection of sources to process. TIMERANG...Time range of the data to be copied. In order: Start day, hour, min. sec, end day, hour, min. sec. Days relative to ref. date. STOKES.....The desired Stokes type of the output data: 'I','V','Q','U','IQU','IQUV','IV','RR','LL','RL', 'LR','HALF' (=RR,LL), 'FULL' (=RR,LL,RL,LR), ' ' lives polarization without modification SELBAND....Bandwidth of data to be selected. If more than one IF is present SELBAND is the width of the first IF required. Units = kHz. For data which contain multiple bandwidths/frequencies the task will insist that some form of selection be made by frequency or bandwidth. SELFREQ....Frequency of data to be selected. If more than one IF is present SELFREQ is the frequency of the first IF required. Units = MHz. FREQID.....Frequency identifier to select (you may determine which is applicable from the OPTYPE='SCAN' listing produced by LISTR). If either SELBAND or SELFREQ are set, their values override that of FREQID. However, setting SELBAND and SELFREQ may result in an ambiguity. In that case, the task will request that you use FREQID. BIF........First IF to copy. 0=>all. EIF........Highest IF to copy. 0=>all higher than BIF BCHAN......First channel to copy. 0=>all. ECHAN......Highest channel to copy. 0=>all higher than BIF SUBARRAY...Subarray number to copy. 0=>all. DOCALIB....If true (>0), calibrate the data using information in the specified Cal (CL) table for multi-source or SN table for single-source data. Also calibrate the weights unless DOCALIB > 99 (use this for old non-physical weights). GAINUSE....version number of the CL table to apply to multi source files or the SN table for single source files. 0 => highest. DOPOL......If > 0 then correct data for instrumental polarization as represented in the AN table. This correction is only useful if PCAL has been run or feed polarization parameters have been otherwise obtained. See HELP DOPOL for available correction modes. BLVER......Version number of the baseline based calibration (BL) table to appply. <0 => apply no BL table, 0 => highest. FLAGVER....specifies the version of the flagging table to be applied. 0 => highest numbered table. <0 => no flagging to be applied. DOBAND.....If true (>0) then correct the data for the shape of the antenna bandpasses using the BP table specified by BPVER. The correction has five modes: (a) if DOBAND=1 all entries for an antenna in the table are averaged together before correcting the data. (b) if DOBAND=2 the entry nearest in time (including solution weights) is used to correct the data. (c) if DOBAND=3 the table entries are interpolated in time (using solution weights) and the data are then corrected. (d) if DOBAND=4 the entry nearest in time (ignoring solution weights) is used to correct the data. (e) if DOBAND=5 the table entries are interpolated in time (ignoring solution weights) and the data are then corrected. BPVER......Specifies the version of the BP table to be applied if DOBAND > 0. 0 => highest numbered table. <0 => no bandpass correction to be applied. SMOOTH.....Specifies the type of spectral smoothing to be applied to a uv database . The default is not to apply any smoothing. The elements of SMOOTH are as follows: SMOOTH(1) = type of smoothing to apply: 0 => no smoothing To smooth before applying bandpass calibration 1 => Hanning, 2 => Gaussian, 3 => Boxcar, 4 => Sinc To smooth after applying bandpass calibration 5 => Hanning, 6 => Gaussian, 7 => Boxcar, 8 => Sinc SMOOTH(2) = the "diameter" of the function, i.e. width between first nulls of Hanning triangle and sinc function, FWHM of Gaussian, width of Boxcar. Defaults (if < 0.1) are 4, 2, 2 and 3 channels for SMOOTH(1) = 1 - 4 and 5 - 8, resp. SMOOTH(3) = the diameter over which the convolving function has value - in channels. Defaults: 1,3,1,4 times SMOOTH(2) used when input SMOOTH(3) < net SMOOTH(2). OUTNAME....Output UV file name (name). Used, if the selected sources assembled in one multiple source file. In the split option OUTNAME is the first 12 characters of the name of the source. OUTCLASS...Output UV file name (class). Standard defaults. OUTSEQ.....Output UV file name (seq. #). 0 => highest unique If QUAL = -1, OUTSEQ must be zero if there are in fact more than one qualifier for a given source name. OUTDISK....Disk drive # of output UV file. 0 => highest with space for the file. DOUVCOMP...If true (DOUVCOMP >= 0) the output data is written in compressed format which can result in a substantial reduction in disk space needed but only calibration routines are likely to interprete this data. If input data are in compressed format, the output will be in compressed format also independent on DOUVCOMP. APARM......Control information: If APARM(1) is equal to 1 then frequency channels selected by ICHANSEL in each IF will be averaged to produce one spectral channel per IF in the output. CHANNEL, CHINC are not used If APARM(1) is equal to 2, then the frequency channels selected by ICHANSEL will be averaged in each IF and then all IF's will be averaged. This produces a one spectral-channel, one IF output or complete spectral averaging of (calibrated) data. WARNING: the output frequency will be corrected to the averaged frequency as will the values of u,v,w, but any IF-dependent editing will make this correction less than accurate. Also the output data are computed by a weighted average while the frequency is a straight average. If weights vary significantly between IFs (and they often do) then the corrections to u,v,w will not have been correct and the error will be sample dependent. If APARM(1) is equal to 3 then average each subsequent CHANNEL input frequency channels. Increment by CHINC channels in selecting output channels. (CHINC=0 -> CHINC=CHANNEL). This can be used to diminish output data set size. Note CHANNEL=1, CHINC=2 will output every other channel (after application of calibration, SMOOTH etc). Also note that one may do things like CHANNEL=4, CHINC=3 to produce output channels that are less independent than those in the input. ICHANSEL is not used. If phase rate corrections are to be done as part of the calibration, then the integration time of the input data must be given in APARM(2) to allow for an amplitude correction to correct for the effect of time smearing on the data. Default is no correction. If APARM(3) > 0 then drop the subarray code from the visibility records. If APARM(5) = 0 then SPLAT will pass only cross power data, this is the default mode. If APARM(5)=1 then both cross-power and total-power data will be passed; if APARM(5)=2 then only total-power data will be passed. If APARM(6) > 0, the full 16 character source name is added to the header. The first 8 characters in keyword SOURNAM1, the second 8 in keyword SOURNAM2. If APARM(7) = 0, assemble all selected sources into one multi source file having applied optionnaly calibration and averaging in time and in frequency. If APARM(7) > 0, the selected sources are splitted into separate single source files. ICHANSEL...The channels to be averaged when APARM(1) = 1 or 2 in the form of an array of start and stop channels plus a channel increment and the IF to which they apply. All 0 => BCHAN, ECHAN, 1, 0. ICHANSEL(4,i) gives the IF and 0 means all IFs. Up to 20 groups of these 4 numbers may be specified. Note that the channel numbers are absolute numbers; they are NOT relative to BIF and BCHAN. For instance if your data had a spectral line covering channels 56 - 80, and you wished to exclude channels 1 - 10 and 121 - 128 because of bandpass effects, then you could set APARM(1) = 2, and ICHANSEL = 11, 55, 1, 0, 81, 121, 1, 0 for a 1-IF data set. If you only wished to use every other channel from the second group then you would set ICHANSEL = 11, 55, 0, 0, 81, 121, 2, 0. CHANNEL....Number of subsequent channels to average together. Used when APARM(1) = 3 CHINC......Increment in input channels between output channels. Used only when APARM(1) = 3. 0 -> CHANNEL. SOLINT.....Time of averaging in min. 0 => no averaging BADDISK....A list of disks on which scratch files are not to be placed. This will not affect the output file. ---------------------------------------------------------------- COMMENTS. The assembling option is useful l when delay and fringe rate have become small enough as a result of the first stage of calibration. This fact allows averaging in frequency and time to reduce the volume of the data output. For this data compression operation on VLBI data, the assembling option should be applied after the first stage of calibration had been carried out: ANTAB, FRING, ACCOR, PCCOR. SPLAT does not copy CL, GC, PC, SN, TY tables if calibration is applied (DOCALIB > 0). The calibration on the basis of these tables has to be carried out before SPLAT (assembling option). In particular it is not good idea to run SPLAT (assembling option) with DOCALIB>0 if PCCOR has not run to create calibration on the basis of pulse-cal tones.