fo - fold freq switched data

fo		fold the data in stack 1.

Fold does a weighted average of the channels around the 'signal' channel
with the negative of those around the 'reference' channel in stack 1. Only
channels with overlap are retained in the final spectrum.

Fold sets the '4' bit in the header variable 'nprc'. It will refuse to fold
data which was not frequency switched or has been previously folded.

This document was last updated on Tue Oct 17 16:24:05 EDT 2000 by Marc W. Pound.