{TAIL ~ a plurality} of level control units receiving said modified signals and providing {HEAD ~ normalized modified signals} having a constant amplitude 
{ TAIL ~ a plurality } of level control units receiving said modified signals and providing { HEAD ~ normalized modified signals } having a constant amplitude
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH