One of the tape guide rollers, roller R6 is coupled to {TAIL ~ an optical tachometer encoder disk} 80 which generates signal patterns in {HEAD ~ relation} to actual tape velocity in the forward 26 and reverse 28 tape directions 
One of the tape guide rollers , roller R6 is coupled to { TAIL ~ an optical tachometer encoder disk } 80 which generates signal patterns in { HEAD ~ relation } to actual tape velocity in the forward 26 and reverse 28 tape directions
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH