{HEAD ~ The magnitude} of delay is varied between {TAIL ~ these two extremes} by varying the relative levels of operation of the differential sections D1 and D2 
{ HEAD ~ The magnitude } of delay is varied between { TAIL ~ these two extremes } by varying the relative levels of operation of the differential sections D1 and D2
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH