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