Coarse tuning and fine tuning combined high-frequency LC voltage-controlled oscillator and tuning method

Abstract

The invention discloses a coarse tuning and fine tuning combined high-frequency LC voltage-controlled oscillator and a tuning method. The coarse tuning and fine tuning combined high-frequency LC voltage-controlled oscillator consists of an LC resonant network circuit and a common emitter amplifier circuit, wherein the LC resonant network of the circuit is coarsely tuned through the voltage-controlled end by adopting a capacitive impedance form that a variable capacitance diode acts as the reactance in the LC resonant network, is finely tuned through the voltage-controlled end by adopting an inductive reactance branch form that another variable capacitance diode acts as the reactance in the LC resonant network, and has two voltage-controlled tuning ends which are the coarse tuning end and the fine tuning end. By adjusting the magnitude of the reverse bias voltage of the variable capacitance diodes and changing the junction capacitance of the variable capacitance diodes through the combined coarse tuning and fine tuning, the resonant frequency of the resonant network can be changed, and the frequency of the output signals can be finally changed. The coarse tuning and fine tuning combined high-frequency LC voltage-controlled oscillator and the tuning method disclosed by the invention are less in components and parts, simple in circuit and larger in application, achieve an economical and efficient method for generating high-frequency oscillators, and can be widely applied to mobile phones, satellite communication terminals, base stations, radars, digital wireless communication systems and other electronic systems.

Description

technical field [0001] The invention belongs to the field of electronic appliances, and relates to a voltage-controlled oscillator, in particular to a high-frequency LC voltage-controlled oscillator combined with coarse and fine tuning and a tuning method. Background technique [0002] There are many ways to realize frequency modulation, which can be roughly divided into two categories, one is direct frequency modulation, and the other is indirect frequency modulation. Direct frequency modulation is to use the modulated signal voltage to directly control the oscillation frequency of the self-excited oscillator (essentially change the fixed frequency component of the oscillator), and the varactor frequency modulation belongs to this category. The varactor diode direct frequency modulation circuit is the most widely used direct frequency modulation circuit at present. The traditional varactor diode direct frequency modulation LC voltage-controlled oscillator has low center fre...

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Problems solved by technology

The feedback signal is taken from both ends of the capacitor. Since the capacitor has a small capacitive reactance to the high-order harmonics, the high-order harmonic components in the feedback signal are small, so the oscillation output waveform is good, but the frequency nonlinearity of the output band of the capacitor three-point oscillator Large, low center frequency stability

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