; PHASE ;--------------------------------------------------------------- ;! Baseline Phase coherence measurement ;# TASK UV IMAGING ;----------------------------------------------------------------------- ;; Copyright (C) 1995 ;; 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 ;----------------------------------------------------------------------- ;--------------------------------------------------------------- PHASE LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC PHASE: Baseline dependent time averaging of "BT" order uv data INNAME Input UV data (name) INCLASS Input UV data (class) INSEQ Input UV data (seq. #) INDISK Input UV data disk # OUTNAME Output uvdata name (name) OUTCLASS Output uv data class OUTDISK Output uvdata disk # OUTSEQ -1.0 32000.0 Output seq. no. APARM (1) Max Coherent ave time (2) Max SNR deviation to pass (4) Min Vector/Scalar ratio (5)>0 = Coherent Average ` (6) Interval to write out data (minutes) (10) Prtlev, (# baselines) BADDISK Disk #'s to avoid ---------------------------------------------------------------- PHASE Type: WARNING, WARNING, Verrry Experimental Task WARNING. Use: Baseline dependent estimation of coherence time, automatic flagging of data and coherenct time averaging of UV-data. NB: data must be sorted to 'BT' order before running. Adverbs: INNAME.....Input UV data file (name). Standard defaults. INCLASS....Input UV data file (class). Standard defaults. INSEQ......Input UV data file (seq. #). 0 => highest. INDISK.....Input UV data file disk #. 0 => any. OUTNAME....Output UV data name (name). Standard defaults. OUTCLASS...Output UV data file (class). OUTDISK....The disk # of output data. 0 => highest with space. OUTSEQ.....Output sequence number. 0 => new file. APARM.....Task enrichment parameters. (1) This gives the maximum averaging time in seconds, 0=> infinite. This parameter may be necessary if subsequent editing or self calibration is required. (2) Max SNR deviation to pass. While calculating the coherence time, the mean and rms of each baseline is calculated. If the value of a visibility exceed A(2) times the RMS, the correlator is flagged. (3) No longer used. (4) Min Vector/Scalar amplitude ratio. The ratio of the vector to scalar amplitude of the real and imaginary parts of the correlator output is calculated for the average of a few visibilities. When the ratio becomes less than A(4) the coherence time is said to be exceeded. A(4) = 0.9 is good for many applications. (5) if A(5) > 0 then the output data are averaged (smoothed) over the coherence time for the baseline (6) Interval to write out data. The data should be written out at an interval of 1/2 the coherence time. BADDISK...Disk #'s to avoid for scratch files ---------------------------------------------------------------- Documentor: Glen Langston An output of PHASE is the minimum coherence time for all baselines. This result is placed in the output uvdata header.