VOLTAGE-CONTROLLED OSCILLATOR AND METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a voltage-controlled oscillator(VCO), having a wide frequency range which does not require physical trimming. SOLUTION: A VCO (38) is provided with an LC tank (20) and a capacitor bank (21). The LC tank (20) is provided with an inductor (12) and a varactor (14). The capacitive output of the varactor is controlled by a control voltageυ. In order to electronically tune the VCO, one pair of capacitors (24) in the capacitor bank (21) is permitted by a digital control signal, based on frequency comparison with the desired frequency. When the capacitor bank is set once, a frequency can be locked to the desired frequency by a phase-locked loop.