{HEAD ~ The control voltage UST} is coupled to a half wave rectifier D, which produces {TAIL ~ a half wave voltage signal} 
{ HEAD ~ The control voltage UST } is coupled to a half wave rectifier D , which produces { TAIL ~ a half wave voltage signal }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL