Again, in {TAIL ~ response} to positive going pulses in such train of pulses, {HEAD ~ transistor Q2} is driven from a non conducting condition to a conducting condition, as shown in FIG 4B 
Again , in { TAIL ~ response } to positive going pulses in such train of pulses , { HEAD ~ transistor Q2 } is driven from a non conducting condition to a conducting condition , as shown in FIG 4B
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH