An improved decoder 17, wherein said reference frequency is in {HEAD ~ the range} of {TAIL ~ 250 Hz} to 6 kHz 
of
An improved decoder 17 , wherein said reference frequency is in { HEAD ~ the range } of { TAIL ~ 250 Hz } to 6 kHz
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH