{TAIL ~ a self test amplifier} connected to the self test oscillator via {HEAD ~ a mixer} to amplify the testing signals created by the self test oscillator; and 
{ TAIL ~ a self test amplifier } connected to the self test oscillator via { HEAD ~ a mixer } to amplify the testing signals created by the self test oscillator ; and
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL 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