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