{HEAD ~ Fault tolerant sync mark detector} for comparing a sign and {TAIL ~ magnitude} of a detected sequence to a target sync mark in sampled amplitude magnetic recording 
for comparing
{ HEAD ~ Fault tolerant sync mark detector } for comparing a sign and { TAIL ~ magnitude } of a detected sequence to a target sync mark in sampled amplitude magnetic recording
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH