Voltage-controlled tuning frequency selection network

Abstract

The invention discloses a voltage-controlled tuning frequency selection network, and the network comprises a power supply filter circuit, an LC resonance circuit, an access capacitor, a feedback circuit and three ports P1, P2 and P3. The LC resonance circuit adopts a variable capacitance diode Cv, an inductor L, a capacitor Cs and a capacitor C3, which are all connected in series to form an LC resonance loop, so that a function of selecting signal frequency is realized. A controllable voltage source is connected with the two ends of the variable capacitance diode through the power supply filter circuit, wherein the capacitance value of the variable capacitance diode can be conveniently changed, and the signal frequency selection intellectualization is achieved. The feedback circuit is composed of a capacitor C1 and a capacitor C2 and connects a part of output signals of the active device to the input port so as to form positive feedback oscillation. An access capacitor Cx is connectedbetween the LC resonance circuit and the feedback circuit. Compared with the prior art, the LC resonance circuit has the advantages that the value of Cx is small, so that large capacitive reactance isshown on a radio frequency signal, only a small part of the radio frequency signal of the LC resonance circuit enters an active device, the influence of interpolar capacitance of the active device ona resonant network can be obviously reduced, and the frequency stability is improved.

Description

technical field [0001] The invention relates to a tuned frequency-selective network, in particular to a voltage-controlled tuned frequency-selected network with adjustable resonant frequency. Background technique [0002] The current tuning network usually uses a three-point LC oscillating circuit. Its disadvantage is that it is inconvenient to adjust the frequency. It is suitable for the case of using a fixed oscillating frequency, and it is easily affected by the capacitance between electrodes, and the frequency stability is poor. Contents of the invention [0003] The object of the present invention is to provide a voltage-controlled tuning frequency-selective network for oscillators with adjustable resonance frequency. The tuning frequency-selective network can adjust the resonance frequency through voltage and improve the frequency stability of the resonance circuit. [0004] Technical scheme of the present invention is: [0005] A voltage-controlled tuning frequency...

AI Technical Summary

Problems solved by technology

[0002] The current tuning network usually uses a three-point LC oscillating circuit. Its disadvantage is that it is inconvenient to adjust the frequency. It is suitable for the situation of using a fixed oscillating frequency, and it is easily affected by the inter-electrode capacitance, and the frequency stability is poor.

Images