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