High frequency dual band output oscillator

摘要

A voltage-controlled oscillator used for a mobile communication system such as a cellular phone or video device. The output from a first output oscillator circuit (1a) is coupled to a wideband buffer amplifier circuit (4) through a coupling capacitor (22). The output from a second output oscillator circuit (1b) is coupled to the wideband buffer amplifier circuit (4) through a frequency selection filter (3a, 3b) and the coupling capacitor (22). A switch terminal (2) is provided on the first or second output oscillator circuit, and the output signal is selected from one of the output oscillator circuits depending on the state of a control voltage appearing on the switch terminal (2).