IdxInLogicalChan
This is a Data Header variable.
Type = Short
Each logical channel in the VSA is either a single physical channel, or an combination of physical channels like Ch1+jCh2. If a combination of physical channels like Ch1+jCh2 is being used, then IdxInLogicalChan is set in Raw Main Time traces, to indicate whether a particular Raw Main Time trace is the first channel or the second one of the logical channel.