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