Various circuits are described to generate {TAIL ~ the Q.E.D. signal} and {HEAD ~ the essential properties} of the signal are defined 
Various circuits are described to generate { TAIL ~ the Q.E.D. signal } and { HEAD ~ the essential properties } of the signal are defined
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH