	CB1 averages both polarizations of the first filter bank
	for the scans in the ASTACK array.  It is assumed that the data
	are in parallel mode (.01 and .02 subscan numbers).  Any
	subscan numbers present in the scan numbers of the ASTACK
	array are ignored.  There is no check for duplicate scan
	numbers.

	This procedure uses PSTACK to perform the ACCUM.

	File name: cb1.prc

	This procedure is included in LSETUP.12meter
