The adder 230 adds the input from each of {HEAD ~ the above described multipliers} 226, 227, 228 and 229 and {TAIL ~ the reference voltage} 231 so as to output the results a the addition 
The adder 230 adds the input from each of { HEAD ~ the above described multipliers } 226 , 227 , 228 and 229 and { TAIL ~ the reference voltage } 231 so as to output the results a the addition
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH