a second multiplier coupled to said second signal and a second local reference signal and having as an output a fourth signal, said second local reference signal phase offset from {HEAD ~ said first local reference signal} by {TAIL ~ 90 degrees}, 
by
a second multiplier coupled to said second signal and a second local reference signal and having as an output a fourth signal , said second local reference signal phase offset from { HEAD ~ said first local reference signal } by { TAIL ~ 90 degrees } ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH