JPS61273004A - Voltage controlled oscillator - Google Patents

Abstract

PURPOSE:To attain stable frequency control by approaching a conductor plate charged to earth potential in the vicinity of a signal electrode exposed from a dielectric resonator and turning the conductor plate externally from the metallic case while using another element externally from the dielectric resonator. CONSTITUTION:The dielectric resonator 14 is arranged and connected on the conductor pattern 16' whose potential is the earth potential so as to bring the potential of the surface of the dielectric resonator 14 to the earth potential. The signal electrode terminal 14'' of the dielectric resonator 14 is connected onto other conductor pattern 16''. The base 16 formed in this way is contained in the metallic case 17 together with a conductor turning element 19. Then the conductor turning element 19 is placed near the electrode terminal 14'' of the dielectric resonator 14 while being charged to the earth potential. Thus, the electrode terminal 14'' of the dielectric resonator 14 has an area opposed to the earth plane changing in response to the turning position of the conductor turning element 19 and its resonance frequency is changed. Thus, the resonator known with the characteristic in advance is used and the conductor with the earth potential is approached in the vicinity of the electrode so as to change the natural resonance frequency of the dielectric resonator.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a voltage controlled oscillator whose resonant frequency is externally variable.

[Background of the invention]

A typical voltage controlled oscillator circuit will be explained using FIG. In the figure, 1 is an oscillation transistor, 2 to 5 are resistors, 6 to 13 are capacitors, 14 is a dielectric resonator, 1
5 is a varactor diode. In a circuit having such a configuration, when a power supply voltage vcc is applied, an oscillator is formed by the common base transistor 1 and its peripheral elements. Here, the oscillation frequency is the externally applied DC potential vt
The frequency is controlled by changing the equivalent capacitance of the varactor diode 150 according to Vc. Another major factor that causes the frequency to change is the natural resonant frequency of the dielectric resonator 14. When a voltage controlled oscillator is incorporated into a circuit to obtain a certain function, a predetermined resonant frequency must be obtained at a predetermined voltage Vt.

Conventionally, as shown in FIG. 5, a microstrip line conductor 14' corresponding to the function of a dielectric resonator was used in a board incorporating the resonant circuit shown in FIG. 4 (some parts are omitted). The frequency is changed by cutting out the shaded part 14'' as necessary.This method is very inconvenient because it cannot be adjusted when stored in a case.

Furthermore, as shown in Japanese Patent Publication No. 59-45241 and FIG. The resonant frequency is controlled by changing the However, with this method, it is difficult to set the resonant frequency of only the dielectric resonator in advance, and position adjustment screws must be inserted and removed as necessary. Also,
It is also time-consuming to process screws in a small dielectric part, which is disadvantageous when making the shape of a dielectric resonator smaller. [Object of the Invention] The object of the present invention is to provide a voltage controlled oscillator which can stably control the frequency using another element from outside the dielectric resonator, while eliminating the drawbacks.

[Summary of the invention]

To achieve this objective, the present invention uses a dielectric resonator whose external surface is charged to earth potential, and places a conductor charged to earth potential near the signal side electrode exposed from the resonator. The feature is that the resonant frequency of the dielectric resonator can be adjusted by placing the plates close to each other and rotating the conductive plate from outside the metal case. 1 is a schematic perspective view showing an embodiment of a voltage controlled oscillator incorporating a dielectric oscillator according to the present invention, in which 5 is a resistor, 10, 12, and 13 are capacitors, and 14 is a A dielectric resonator, 14'' is an electrode of the dielectric resonator, 15 is a varactor diode, 16 is a printed circuit board, and 16' and 16'' are conductor patterns on the printed circuit board 16.

FIG. 2 is a cross-sectional view of this embodiment, where 17 is a metal case, 19 is a conductive rotating element, and parts corresponding to those in FIG. 1 are given the same reference numerals. FIG. 3 is a perspective view showing a specific structure of the conductive rotating element in FIG. 2;

In FIGS. 1 to 3, a dielectric resonator 14 is connected and arranged on a conductor pattern 16' at a ground potential, and the surface of the dielectric resonator 140 is set at a ground potential. The signal side electrode terminal 14'' of this dielectric resonator 14 is connected to another conductor pattern 16.
“Connect on top.

As seen in the sectional view of FIG. 2, the substrate 16 thus formed together with the conductive rotating element 19 schematically shown in FIG.
It is housed in a metal case 17.

At this time, the conductor rotating element 19 is placed near the electrode terminal 14'' of the dielectric resonator 14 and charged to a ground potential.Thereby, the electrode terminal 14'' of the dielectric resonator 14 is placed at the rotation position of the conductor rotating element 190. Accordingly, the area facing the ground plane changes and the resonant frequency also changes.

By using a resonator whose characteristics have been obtained in advance in this manner and bringing a conductive object at ground potential close to the electrode portion of the resonator, the natural resonant frequency of the dielectric resonator can be changed.

According to this embodiment, even when the departure circuit is housed in the case, it can be freely operated, which is very convenient. Moreover, if the conductor rotating element 19 is fixed after setting the frequency, the frequency can be stabilized.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to control the frequency by using a dielectric resonator that maintains the characteristics as a resonator in advance and by utilizing the frequency change of the resonant circuit due to the approach of a metal object. Therefore, it is possible to provide a voltage controlled oscillator that can be housed in a small metal case and has excellent functions without the drawbacks of the above-mentioned prior art.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing an embodiment of a voltage controlled oscillator according to the present invention, FIG. 2 is a sectional view showing the main parts thereof, and FIG. 3 is a schematic perspective view showing a conductive rotating element used in the present invention. , 4th
5 is a schematic plan view of a conventional example, and FIG. 6 is a partial cross-sectional view of another conventional example. 1---Oscillation transistor, 14---Dielectric resonator, 14"---Signal side electrode of dielectric resonator, 16---Substrate, 17---・Metal case, 1
9. Shaft/conductor plate (conductor rotating element). Agent Masu Masuo Katsutoshi Ogawa - 1' Kashi 1 Kuchishima 2

Claims (1)

[Claims] In a voltage-controlled oscillator in which an oscillation element and a dielectric resonator formed on a substrate are housed in a metal case, a dielectric resonator whose external surface is charged to a ground potential is used, and the external surface is exposed from the resonator. A voltage-controlled oscillator in which the resonant frequency of the dielectric resonator can be adjusted by placing a conductor plate charged to a ground potential close to the signal side electrode and rotating the conductor plate from outside the metal case. .