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