The occurrence of the pulses are compared digitally resulting in {HEAD ~ an analog control signal} for {TAIL ~ the adjustment} of the work piece drive 
for
The occurrence of the pulses are compared digitally resulting in { HEAD ~ an analog control signal } for { TAIL ~ the adjustment } of the work piece drive
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH