The low frequency amplifier 304 is typically {HEAD ~ a switch voltage supply}, in which one of a plurality of fixed voltage supplies is selected in {TAIL ~ dependence} upon a current input signal 
The low frequency amplifier 304 is typically { HEAD ~ a switch voltage supply } , in which one of a plurality of fixed voltage supplies is selected in { TAIL ~ dependence } upon a current input signal
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH