Using das-merge

For observations using the DAS it is necessary to remember that for all but the narrowest bandwidth (125 MHz) the spectrum obtained consists of 2, 4, or 8 subbands. As noted elsewhere, these subbands are contiguous in channel space, but overlap in frequency/velocity space. Each subband has edge effects which should be removed before gluing the spectrum together. The function das-merge uses a specified number of overlap channels from the ends of each subband to average the overlap regions, optionally with vertical realignment of the subbands.