{TAIL ~ control} means for introducing {HEAD ~ dynamic operational signals} to the chip , so as to cause instantaneous operational voltages at selected test points as a function of operation 
{ TAIL ~ control } means for introducing { HEAD ~ dynamic operational signals } to the chip , so as to cause instantaneous operational voltages at selected test points as a function of operation
TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH