A voltage controlled oscillator

摘要

A voltage controlled oscillator for wide tuning range of frequency with less phase noise has a bipolar transistor (1) provided with a positive feedback circuit between a base (11) and an emitter (13) of said transistor (1), an impedance matching circuit (20) coupled with a collector (12) of said transistor (1) and an output terminal (10), a resistor (8) coupled between the base (11) of said transistor (1) and a control source (14) which provides control voltage for adjusting oscillation frequency of the oscillator. The base (11) of the transistor (1) shows capacitive negative impedance, and an inductive element (2) is coupled with the base (11) of said transistor (1) for oscillation. The emitter (13) of said transistor (1) is grounded for D.C. voltage through an inductor (6) or a transmission line (4), or coupled with a control voltage (16).