Referring now to FIG 1 {HEAD ~ an input digital word}, representing {TAIL ~ a desired carrier frequency}, is input to an adder 12 
representing
Referring now to FIG 1 { HEAD ~ an input digital word } , representing { TAIL ~ a desired carrier frequency } , is input to an adder 12
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH