JPS6246323Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a surface acoustic wave oscillator used in the oscillation section of wireless equipment.

Structure of a conventional example and its problems A conventional surface acoustic wave oscillator is structured as shown in FIG. That is, printed circuit board 1
A surface acoustic wave delay element 2, an amplifier circuit 5, and impedance matching circuits 3 and 4 of the surface acoustic wave delay element 2 and the amplifier circuit 5 are configured,
A ground terminal 6, a power terminal 7, and an output terminal 8 are electrically connected to each other by a copper foil pattern 10, and the entire printed circuit board 1 is surrounded by a shielding case 9.
It was covered with

However, since such a conventional surface acoustic wave oscillator is constructed on a single printed circuit board 1, its external dimensions are large, which hinders miniaturization of wireless equipment. Furthermore, during manufacturing, it is difficult to independently test the performance of the surface acoustic wave delay element 2 and the amplifier circuit 5, which hinders improvement in yield.

Purpose of the invention The present invention eliminates the above-mentioned conventional drawbacks, and aims to provide a surface acoustic wave oscillator that can be miniaturized, improve manufacturing yield, and facilitate manufacturing.

Composition of the Invention In order to achieve the above object, the surface acoustic wave oscillator of the present invention comprises a first printed circuit board that constitutes a surface acoustic wave delay circuit, and an amplifier circuit that provides feedback to the surface acoustic wave delay circuit. and the second printed circuit board are joined with their backs facing each other,
The surface acoustic wave delay circuit and the amplifier circuit are electrically connected, an output terminal, a ground terminal, and a power terminal are provided on a second printed circuit board, and the first and second printed circuit boards are entirely covered with a shield case. It has an ivy configuration.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on the drawings. In FIGS. 2 to 4, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted.

In FIG. 2, a surface acoustic wave delay element 2 and impedance matching circuits 3 and 4 between the surface acoustic wave delay element 2 and an amplifier circuit 5 (FIG. 3) are mounted on a first printed circuit board 11. It is configured,
These surface acoustic wave delay elements 2 and impedance matching circuits 3 and 4 are connected to copper foil patterns 13 and 14.
electrically connected. Furthermore, copper foil patterns 12 and 15 for connection to the amplifier circuit 5 are formed on the printed circuit board 11.

In FIG. 3, an amplifier circuit 5 is configured on a second printed circuit board 16, and a copper foil pattern 1 for connecting to a surface acoustic wave delay element 2 is provided.
7 and 18 are formed, and copper foil patterns 19, 20, and 21 for connection to the ground terminal 6, power supply terminal 7, and output terminal 8 (FIG. 4), respectively, are formed.

In FIG. 4, the two printed circuit boards 1
1 and 16 are joined to each other on their backs, and copper foil patterns 12 and 17, 15 and 18 are electrically connected using electric wires, through holes, or the like. In addition, the copper foil pattern 19 of the printed circuit board 16,
A ground terminal 6, a power supply terminal 7, and an output terminal 8 are connected to the terminals 20 and 21, respectively. Further, the printed circuit boards 11 and 16 are entirely covered with a shield case 22.

Note that at least one of the two printed circuit boards 11 and 16 may be a double-sided printed circuit board, and the back surface thereof may be used as a ground electrode, which may be electrically connected to the ground terminal 6. In this way, adverse effects such as coupling due to stray capacitance between the surface acoustic wave delay element 2 and the amplifier circuit 5 can be eliminated. This effect becomes larger as the frequency becomes higher.

Effects of the invention As explained above, according to the invention, the external dimensions are reduced, making it possible to downsize wireless equipment, and since the surface acoustic wave delay circuit section and the amplifier circuit section are configured independently. Since characteristics can be independently inspected during manufacturing and only non-defective products can be combined, yield can be improved.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional front view of a conventional surface acoustic wave oscillator, Fig. 2 is a front view of a printed circuit board that constitutes a surface acoustic wave delay circuit used in a surface acoustic wave oscillator according to an embodiment of the present invention, and Fig. 3 is the same. FIG. 4 is a front view of a printed circuit board that constitutes an amplifier circuit used in a surface acoustic wave oscillator, and FIG. 4 is a longitudinal sectional side view of the same surface acoustic wave oscillator. 2...Surface acoustic wave delay element, 5...Amplification circuit,
6... Earth terminal, 7... Power terminal, 8... Output terminal, 11... First printed circuit board, 16... Second printed circuit board, 22... Shield case.

Claims (1)

[Claims for Utility Model Registration] 1. A first printed circuit board that includes a surface acoustic wave delay circuit and a second printed circuit board that includes an amplifier circuit for providing feedback to the surface acoustic wave delay circuit are placed on the back side of each other. the surface acoustic wave delay circuit and the amplifier circuit are electrically connected, an output terminal, a ground terminal, and a power terminal are provided on the second printed circuit board, and the first and second printed circuit boards are connected together. A surface acoustic wave oscillator whose entire board is covered with a shield case. 2. The surface acoustic wave oscillator according to claim 1, wherein at least one of the first and second printed circuit boards is a double-sided printed circuit board, and the back side of the printed circuit board is a ground electrode.