{TAIL ~ The first sub path} extracts the second order intermodulation component from the path tuning signal of {HEAD ~ the main path} 
{ TAIL ~ The first sub path } extracts the second order intermodulation component from the path tuning signal of { HEAD ~ the main path }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD