{TAIL ~ The pulse train} fed to {HEAD ~ the base} of transistor Q1 has a period P and a duty cycle less than 50 percent 
{ TAIL ~ The pulse train } fed to { HEAD ~ the base } of transistor Q1 has a period P and a duty cycle less than 50 percent
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH