Getting Information After UVREAD

Table 2.5: Arguments to UVINFO

Object	Units	No. Values Returned
restfreq	GHz	nread
velocity	km/s	nread
bandwidth	GHz	nread
frequency	GHz	nread
sfreq	GHz	nread
visno		1
line		6
amprange	(flux units)	3

The routine uvinfo returns information about the data returned by the last call to uvread. The argument object is a character string indicating the information that is desired. The argument data is a double precision array, containing the returned information. Possible values for object are:

'restfreq'

Data contains the rest frequency (GHz) for each channel returned by uvread.

'velocity'

Data contains the velocity (km/s) for each channel returned by uvread.

'frequency'

Data contains the frequency (GHz) of the channel returned by uvread, after removing the doppler contribution.

'bandwidth'

Data contains the bandwidth (GHz) of each channel returned by uvread.

'sfreq'

Data contains the sky frequency (GHz) of each channel returned by uvread.

'visno'

Data contains a single number, which is the visibility number (running from 1 upwards) of the last channel read.

'amprange'

Data contains three values. The first value indicate the sort of amplitude selection that was requested for this record, and the second and third values give a flux range. Possible value of data(1) are -1 (data outside the range [data(2),data(3)] were rejected), 0 (no amplitude selection was active) or +1 (data inside the range [data(2),data(3)] were rejected).

For example, consider the following code fragment.

      integer maxchan
      parameter(maxchan=512)
      integer tno,nread
      complex data(maxchan)
      logical flags(maxchan)
      double precision preamble(4),velocity(maxchan)
           .
           .
           .
      call uvread(tno,preamble,data,flags,maxchan,nread)
      call uvinfo(tno,'velocity',velocity)

After the call to uvinfo will contain the velocity of each channel read by uvread.