Patent ID: 7132897

Claim:
A method for producing an analog control voltage (VC) for a voltage controlled oscillator having one analog control voltage input in a circuit arrangement including a phase locked loop ( 10 ), said method comprising the following steps: a) setting said control voltage (VC) to a predetermined starting control voltage value (VC — 1); b) generating respective counting sequences ( 160 , 174 , 178 , 180 , 182 , 184 ) in a main frequency divider ( 14 ) and in a reference frequency divider ( 18 ) and synchronizing counting beginnings of both said counting sequences, with each other; c) determining during an actual counting sequence of said counting sequences, an actual oscillator control voltage (VC(t)); said actual oscillator control voltage being effective during said actual counting sequence; d) calculating, based on said actual oscillator control voltage (VC(t)), a first new oscillator control voltage (VC(t+1)) that is larger than said actual oscillator control voltage to provide a first voltage difference; e) further calculating, based on said actual oscillator control voltage (VC(t)), a second new oscillator control voltage (VC(t+1)) that is smaller than said actual oscillator control voltage to provide a second voltage difference; f) varying said control voltage (VC) in accordance with said first voltage difference in a first direction in response to said reference frequency divider completing a counting sequence prior to said main frequency divider completing a counting sequence; and g) further varying said control voltage (VC) in accordance with said second voltage difference in a second direction opposite said first direction in response to said main frequency divider completing a counting sequence prior to said reference frequency divider completing a counting sequence.