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