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 name QUAL -10.0 Calibrator qualifier -1=>all CALCODE Calibrator code ' '=>all STOKES Stokes of output TIMERANG Time range to use SELBAND Bandwidth to select (kHz) SELFREQ Frequency to select (MHz) FREQID Freq. ID to select. SUBARRAY 0.0 1000.0 Sub-array, 0=>all BIF Low IF number to do EIF Highest IF number to do BCHAN 0.0 First channel included ECHAN 0.0 last channel included ANTENNAS Antennas to include BASELINE Baselines with ANTENNAS 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 >0.5 correct polarization. PDVER PD table to apply (DOPOL>0) BLVER BL table to apply. FLAGVER Flag table version DOBAND -1.0 10.0 If >0.5 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. SOLINT 0.0 Basic integration time in the UV data DOPLOT 0.0 4.0 Selects which parameter is plotted (1-4 see help) NPLOTS -1.0 Number of plots per page -1 -> plot average over all baselines FUNCTYPE 'LG' log in Y, linear in X 'L2' log in X and in Y DOEBAR -1.0 1.0 > 0 => plot error bars FACTOR Scale symbols by FACTOR SYMBOL 0.0 24.0 Plot symbol number: 1 - 24 0 -> 3 (circle) LTYPE -410.0 410.0 Type of labeling: 1 border, 2 no ticks, 3 - 6 standard, 7 - 10 only tick labels <0 -> no date/time PIXRANGE PIXR(2)>PIXR(1) -> fixed y-axis range DOTV -1.0 1.0 > 0 Do plot on the TV, else make a plot file GRCHAN 0.0 8.0 Graphics channel 0 => 1. XYRATIO 0.0 X/Y ratio 0 -> fit TV or 1 PL

ALVAR Task: This task computes the vector average of the included spectral channels and IFs making a grid of data at intervals of SOLINT in time. It then computes the Allan Variance at each possible integration time "tau = i * SOLINT". If AV(j) is the average at a particular tau, the Allan Variance is given by sigma^2(tau) = < (AV(j+2) - 2AV(j+1) + AV(j))^2 > / (2 tau) The task then plots sigma^2 as a function of tau for all possible values of tau. The input data must be in time order. The task is able to handle gaps (in time) should they arise but the computation is made more complex and less reliable by such gaps. One long scan would really be best. It prints the mean, rms, robust mean, and robust rms for each baseline and IF. Spectral channels BCHAN-ECHAN are averaged within the SOLINT and tau == SOLINT. The display is in 2 groups of 4 columns, one row per baseline, Stokes, and IF. The first 2 columns are the mean square Allan variance of vector difference (IM2- 2*IM1 + IM0)**2 + (RE2 - 2*RE1 + RE0)**2 where (RE2,IM2) is the amplitude normalized vis at point n+2, (RE1,IM1) is the normalized vis at n+1, etc. plus the rms of means square variance. The second pair of columns is Allan variance in phase (PH2 - 2*PH1 + PH0)**2 with minimization of 2 pi amibiguities. The second group of four columns are the same, but with the mean square variance and rms computed by robust means. Note that phases are in radians. 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 to be copied. ' '=> all; if any starts with a '-' then all except ANY source named. QUAL.......Qualifier of source to be copied. -1 => all. CALCODE....Calibrator code of sources to copy. ' '=> all. STOKES.....Specifies which STOKES parameters are written in the output data set: ' ' => 'FULL' 'I','Q','U','V', 'IV', 'IQU', 'IQUV' 'RR','LL', 'RL', 'LR', 'RRLL', 'RLLR', 'RLRL' 'XX','YY', 'XY', 'YX', 'XXYY', 'XYYX', 'XYXY' 'HALF', 'CROS', and 'FULL' have sensible interpretations depending on the Stokes present in the data. The last in each of the 3 rows above == 'FULL'. Note that many combinations of polarizations in the input and values above are not supported. 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. 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. SUBARRAY...Sub-array number to copy. 0=>all. BIF........First IF to include. 0 -> 1. EIF........Last IF to include. 0 -> max. BCHAN......First channel in spectral average. 0=>all. ECHAN......Highest channel in average. 0=>all higher than BCHAN 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 or PD 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: 1 is normal, 2 and 3 are for VLBI. 1-3 use a PD table if available; 6, 7, 8 are the same but use the AN (continuum solution) even if a PD table is present. PDVER......PD table to apply if PCAL was run with SPECTRAL true and 0 < DOPOL < 6. <= 0 => highest. BLVER......Version number of the baseline based calibration (BL) table to apply. <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. IMAGR uses DOBAND as the nearest integer; 0.1 is therefore "false". BPVER......Specifies the version of the BP table to be applied 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). SOLINT.....Pre-averaging time in seconds. 0 -> 10. DOPLOT.....The task computes 4 different Allan variances (1) Mean of vector amplitude of normalized visibilities. (2) Mean of phase adjusted to minimize 2*pi ambiguities (3) Median of vector amplitude of normalized visibilities. (4) Median of phase adjusted to minimize 2*pi ambiguities DOPLOT selects which one is plotted with 0 => 3. NPLOTS.....Number of panels per plotted page. 0 -> 2 -1 => plot the average over all included baselines FUNCTYPE...'L2' log in both X axis (tau) and Y axis (Allan variance) 'LG' log in Y axis, linear in X axis else linear in both FACTOR.....Scale plot symbols by FACTOR 0 -> 1. If FACTOR < 0, draw lines between the points and use abs(FACTOR) to scale the points plotted. SYMBOL.....1: Plus sign (default) 12: Five pointed star 2: Cross (X) 13: Star of David 3: Circle 14: Seven-pointed star 4: Box 15: Eight-pointed star 5: Triangle 16: Nine-pointed star 6: Diamond 17: Ten-pointed star 7: Pentagon 18: 11-pointed star 8: Hexagon 19: 12-pointed star 9: Septagon 20: 13-pointed star 10: Octagon 21: 14-pointed star 11: Nine-gon 22: Plus with gap 23: vertical line 24: Cross with gap 0 -> 3 LTYPE......Labelling type, see HELP LTYPE for details: 1 = border, 2 = no ticks, 3 or 7 = standard, 4 or 8 = relative to ref. pixel, 5 or 9 = relative to subimage (BLC, TRC) center, 6 or 10 = pixels. 7-10 all labels other than tick numbers and axis type are omitted. Less than 0 is the same except that the plot file version number and create time are omitted. Add n * 100 to alter the metric scaling. PIXRANGE...Plot Y axis with this range. Note that on L2 and LG this adverb is in logarithm base 10. DOTV.......> 0 -> use the TV; else make plot file(s) GRCHAN.....Limit plot to one graphics channel; 0 -> use channels 1 (labels), 2 connecting line, and 4 (symbols and error bars). XYRATIO....X/Y plot ratio, 0 -> 1 for plot files, TV dimensions for DOTV true.