{HEAD ~ a first set} of zero coefficients extending along a direction traversing said {TAIL ~ filter} through a center position to form a first side and a second side 
{ HEAD ~ a first set } of zero coefficients extending along a direction traversing said { TAIL ~ filter } through a center position to form a first side and a second side
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH