a second low pass filter coupled to said {TAIL ~ fourth signal} and having as {HEAD ~ an output} a second filtered signal, 
a second low pass filter coupled to said { TAIL ~ fourth signal } and having as { HEAD ~ an output } a second filtered signal ,
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH