'birdie' For CABB data: CABB generates self-interference in a number of channels across the spectrum due to 640 MHz clock harmonics. These birdies are fixed in channel number for each CABB configuration. The birdie option currently knows about the 2048x1MHz continuum mode and flags the affected channels, 100 band edge channels on each side, and, at 20 and 13cm, the unusable parts of the spectrum.
For pre-CABB data: ATCA self-interference can corrupt channels at integral multiples of 128 MHz. The birdie option flags these channels. Additionally, in continuum (33 channels/128MHz) mode, the birdie option dicards every second channel, plus some edge channels. The channels discarded are those most likely affected by the self-interference. Discarding these channels does not have a sensitivity penalty, because the effective channel bandwidth is twice the channel separation. 'reweight' For pre-CABB data: re-weight the lag spectrum to eliminate the "Gibbs" phenomena in continuum data (33 ch/128 MHz); ignored for all other data. 'compress' Write output data in compressed format. 'noauto' Discard autocorrelation data. The default is to copy the autocorrelation data. 'nocross' Discard cross-correlation data. The default is to copy the cross correlation data. 'relax' Do not flag visibilities based on SYSCAL information. The default is to flag visibilities if they have not been preceded by a valid SYSCAL record, or if the the values in the SYSCAL record look bad. SYSCAL values are checked for sampler statistics being within 3% of 17.3%, or 0.5% of 50.0%, that the XY phase is within 10 degrees of its running median, and that the XY amplitudes are within 1 Jy or 10% of its running median. The tests for xy phase and amplitude are skipped for 3mm data (as there is no noise calibration signal). 'mmrelax' This option is ignored, it is only present for historical reasons. 'unflag' Save any data that is flagged. By default ATLOD discards most data that is flagged. 'opcorr' Correct for atmospheric opacity. This option is possible for data measured after October 2003. Because of the way system temperature is measured at 3mm (an "above atmosphere" measurement), it is not appropriate for 3mm data. This option is silently ignored for 3mm data. Generally it is only relevant for 7mm and 12mm observations. It does no harm (and negligible good) for longer wavelengths. 'samcorr' Correct the pre-Dec93 data for incorrect sampler statistics. Since December 1993, sampler corrections are performed online. This option is silently ignored for data measured after December 1993. 'xycorr' Apply the on-line measurements of the XY phase. This option is silently ignored for 3mm data measured before October 2007. 'hanning' Hanning smooth spectra and drop every other channel This option is ignored for 128-MHz, 33-channel data. 'bary' Use the barycentre as the velocity rest frame. The default is to use the LSR frame. 'noif' Do not map the simultaneous IFs to the IF axis. By default ATLOD attempts to map the simultaneous frequencies to the IF axis. This will not be possible if there are a different number of polarisations in the different IFs. 'nopflag' If at least one polarisation of a set of 2 or 4 polarimetric spectra are bad, ATLOD normally flags all of the polarisations. Option nopflag changes this so that only the nominally bad spectrum is flagged. 'hires' Treat bin data as measurements in the high time resolution mode. The output dataset contains no bins, but instead appears as data measured with small cycle times. 'pmps' Undo `poor man's phase switching'. This is an obscure option that you should not generally use. 'single' Assume input is a single dish RPFITS file (from Parkes or Mopra). This is usually used together with option 'relax'. 'caldata' Save visibilities associated with certain system calibrations. Currently this consists of reference pointing calibration and "paddle" measurements. 'nocacal' Flag data that atlod suspects is taken during a CACAL scan. There is potential for error in atlod determining which data are and are not part of a cacal scan. Use this with caution. 'nopol' Discard data that is not "parallel hand" Stokes type. 'rfiflag' Flag channels at frequencies that are known to be bad. This uses the file rfiflag.txt in the current directory or the default version in MIRCAT. The file should contain 2 frequencies per line, the lower and upper end of the rfi in MHz. Precede comments with a '#'. 'notsys' Undo the online Tsys correction. Useful if RFI in the tvchannel range has caused the corrections to be very noisy. The resulting data will be in raw counts scaled down by 10^6. 'nopack' Don't pack the two CABB autocorrelation bins into one bin. The autocorrelation bin 1 and 2 will contain noise cal OFF and ON data. The default is to repack the info into bin 1: XX and YY will contain GTP and SDO data in the real and imaginary part; XY will contain the OFF data and YX will contain the ON-OFF data (for XY). This will allow recalculation of the Tsys and xyphase later.
NOTE: Using this feature to skip many files on a tape is VERY inefficient. It is far faster to skip using operating system commands. When doing this, however, you should be aware is that every RPFITS files consists of 3 tape files. Thus you will want to skip three times as many tape files as RPFITS files. For example, in UNIX, to skip 10 RPFITS files, use
mt -f /dev/nrst0 fsf 30
lod.for,v 1.17 2011/02/11 12:54:31 pteuben Exp $