Voltage controlled oscillator

Abstract

At the same control voltage Vtune, the oscillation frequency with only switches SW3 and SW4 being closed is higher than that with only switches SW1 and SW2 being closed. Accordingly, even when the oscillation frequency is lower than designed with only the switches SW1 and SW2 being closed and the capacitance of varactor diodes D1 and D2 cannot be controlled to provide the desired oscillation frequency, the desired oscillation frequency can be provided by closing only the switches SW3 and SW4 to control the capacitance of the varactor diodes D1 and D2. On the oscillation frequency, a coarse tuning can be performed by controlling the switches SW1 to SW4, while a fine tuning can be performed with the varactor diodes D1 and D2. Consequently, the range of the oscillation frequency is increased.

Dependencies are inferred from the claim text.