In operation, {HEAD ~ the variable delay element} 30 provides {TAIL ~ a variable delay} whose magnitude is directly related to the composite of the degrees of operation of the differential sections D1 and D2 
provides
In operation , { HEAD ~ the variable delay element } 30 provides { TAIL ~ a variable delay } whose magnitude is directly related to the composite of the degrees of operation of the differential sections D1 and D2
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH