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