JPS6199408A - Circuit board for surface wave filter element - Google Patents

Abstract

PURPOSE:To compensate induction of in-phase components, to amplify a desired signal of anti-phase components and to improve an out-band level by equalizing lengths of printed wiring parts of the input terminal and the output terminal of a surface wave filter element on the same surface and amplifying the output of this element with a differential input amplifier. CONSTITUTION:A substrate 40 of a circuit board (b) on which a surface wave filter element 10 is placed consists of a printed wiring part 40 connected to an input terminal 17 of a comb-shaped electrode 1301 of an input electrode 13, printed wiring parts 43 and 44 connected to an output terminal 11 of an output electrode 14, and an earthed part 35 connected to an earth terminal 20 connected to a stem 11. Extending parts 47 and 49 extending in the direction of a wiring part 41 are provided in wiring parts 43 and 44, and distance 56 and 57 from end parts of extending parts 47 and 49 to a hole 51 of the wiring part 41 are equal to each other approximately. Consequently, induction of the same level is received by the differential amplifier and is compensated. Thus, the frequency characteristic of the element 10 is improved to improve the out- band level by about 10dB.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a channel radix for a single surface wave filter element.

[Technical background of the invention and its problems]

Conventionally, a part extending from the printed wiring part in the direction of the input terminal is provided to prevent induction between the input terminal and the output terminal.
Japanese Patent Publication No. 58-52369 C2 discloses a circuit board for a surface wave filter element which aims to improve the frequency characteristics by further lowering the trap point on the frequency characteristic curve by C2. Further, the technology of the cage is disclosed in Tokuko No. 59-25524. by the way.

All of these circuit boards for surface wave filter elements are for round stems. This is seen from the perspective of the current technological trend of reducing the installation area of surface wave filters in television receivers, etc.

When compared with a circuit board for a surface wave filter element in which lead terminals are arranged in a substantially straight line and an inline type stem is used, the arrangement area becomes larger, which goes against the trend of technology. Therefore, surface wave filters using in-line stems are currently becoming mainstream.

However, surface wave filter elements using in-line stems are different from round ones. In other words, the distance from the input terminal to the output terminal is different, and in a circuit using a differential human power IC, the capacitive induction that affects the input terminal to the output terminal becomes unbalanced, which is compensated for by the differential human power IC. There is a danger that things will get worse. This causes a problem in that the out-of-band characteristics deteriorate and it becomes difficult to sufficiently suppress adjacent frequencies. In order to avoid this, there is a method of providing a shield plate between the input and output terminals, but if this is done, there is a risk that the installation area will become large when it is incorporated into a television or the like.

[Purpose of the invention]

The present invention was made in view of the above-mentioned drawbacks C of the conventional circuit board for a surface wave filter element.Special C: A surface wave filter element suitable for a surface wave filter element using a high impedance piezoelectric substrate. The purpose is to provide circuit boards for

[A essential point of the invention]

In order to achieve the above object, the output terminal of the pair of output terminals is fixed in the same direction as the input terminal of the input signal, and an extension part extending on the same plane as the signal input terminal 1 is attached to the constant printed wiring part. This is a circuit board for forming a surface wave filter element.

This improves the out-of-band level.

[Embodiments of the invention]

Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1 (al) and FIG. 1 fbl.

In FIG. 1 (8), the surface wave filter element CICj is attached to a conductive base, such as an in-line type parallel stem (Lυ) via two adhesive members (not shown) such as LiTa0.
NbO.

A piezoelectric substrate α3 consisting of the like is mounted and configured.

On this piezoelectric substrate (13), a pair of comb-shaped electrodes (130
1).

(1302) and a pair of comb-shaped electrodes (1401), which are provided facing each other.

The output "M el (14)" consisting of (1402) is configured.

A sound-absorbing member α9 is installed at the end of the two-voltage electric connector so as to sandwich this manual polarization d31 and the output polarization circle. Wholesalers are attached. On this stem αυ, five lead terminals (171) are arranged in a substantially vertical pattern and implanted into Tomitsu through the glass member u&.Four of these lead terminals αD are connected to the input
and each comb shape with output <ti (13(11)
.

(1302), (1401), and '(1402) are electrically connected via bonding wires 19. f
, the remaining one lead terminal u1 and f8 toothed electric wire M (
The lead □; M element C17) connected to 1302) is grounded to the stem U via a bonding wire.

Next, the lrJ approximate plate on which the surface wave filter element [+01 is mounted and fixed will be explained with reference to Fig. fI1 (m).

In FIG. 1(b) 1-, the circuit board 1/10 has a printed wiring part (411) connected to the signal input terminal t17) of the j/6 IgA heron electrode (1301) of the input electrode housing 3. ,
A printed wiring part t43 (44) connected to the signal output terminal 0D of the output electrode (14), a constant ground terminal ttD+= connected to the stem (Il+), and a grounding part (T) connected to the stem (Il+).
I have heard from you. In addition, holes (51) and (52)
, (53).

(54) and (55) are holes for one lead Mizukoshichi).

The print fitting part +i3 and the print receiving part (extending part t47 extending in the 411 direction), 11
91 is installed.

This extension part t47), (distance (56) between the end of 491 and the hole (51) of printed wiring +413), (5
7) is approximately equal. That is, 1 circuit board false α is +4.5 in the printed wiring section where the output terminal is placed facing the direction of the input terminal No. 1g and the input terminal.

(It is characterized by having an extension part-force, (4j).

However, since the extension attack η, +491 and the respective distances (56) and (57) to the hole (51) are approximately equal, it would be 8 meters to receive the same Belda Yuji with a nine-motion amplifier and compensate. . This a
From 12, as shown in Figure 2, Zhou El Ei's characteristic music section (61
] The trap points (65) and (66) are the conventional trap points (63).

Lowering it below (64) became -J ability. Therefore.

The frequency characteristics of the surface wave filter element 101 could be improved, and the out-of-band level could be improved by approximately 10 dB.

Next, Figure 3 (al, (bl, fc), fd
), other embodiments of the present invention will be described.

In Fig. 3(a), the end face of the printed wiring part (71) into which the input terminal is inserted and the extended part of the printed wiring part (72), (73) into which the output terminal is inserted. Since each short point is approximately equal, an effect equivalent to that of the first embodiment can be obtained.

In FIG. 3(b), third factor (C), and FIG. 3(diC), the printed wiring part (71), the extension part (72),
(73) and the distance from each other is approximately equal. Therefore, FIG. 3 1bl, FIG. 3 1bl, and FIG. 3 1bl have the same effect as the embodiment. It should be noted that the present invention is limited to the following: It goes without saying that the distance from the hole into which the input terminal is inserted to the end of the printed wiring section into which the output terminal is inserted should be equal to n.

[Chomei effect]

In the present invention, the input terminal printed wiring part of the inline stem surface acoustic wave filter element and the output terminal printed wiring part are arranged on the same plane and at equal distances, and the output of this surface acoustic wave filter element is connected to the differential input terminal. By amplifying with an amplifier, the in-phase component is compensated for, and the anti-phase component of the desired signal is amplified, thereby making it possible to improve the out-of-band level.

[Brief explanation of the drawing]

FIG. 1 ta+ to fill (f) I are schematic diagrams showing one embodiment of the circuit board for a surface acoustic wave filter element of the present invention, and FIG.
Figures 1 (fa) to 3 (Fdl) are characteristic curves showing the characteristics of the first curve fbl, and Figures 3 (3) to 3 (Fdl) are schematic diagrams showing other embodiments of the present invention. u(1...Surface wave filter element t131...Input conductivity α4...Output electrode (1301), (1302), (1401)
, (1402)...Comb tooth shape = &αD...4 lead terminals...Circuit board agent Patent attorney Chika Nori, Yu Shi (and 1 other person) Figure 1 Figure 2 f (M+-17)

Claims (1)

[Claims] A piezoelectric substrate having an input electrode and an output electrode each consisting of a pair of comb-shaped electrodes is mounted and fixed on an in-line conductive base on which a plurality of lead terminals are implanted in substantially a straight line,
One of the comb-shaped electrodes constituting the input electrode is electrically connected to the lead terminal directly planted on the base to serve as a ground terminal, and the other of the comb-shaped electrodes constituting the input electrode is connected to the base. A pair of comb-shaped electrodes constituting the output electrode are electrically connected to the lead terminal implanted on the base via an insulating member to serve as a signal input terminal, and are implanted on the base through an insulating member. The surface wave filter element is electrically connected to the provided lead terminals to form a pair of output terminals, and is electrically connected to a circuit board having printed wiring in a predetermined shape via each of the lead terminals. In the circuit board for a surface wave filter, an extending portion extending on the same plane as the signal input terminal is provided on a printed wiring portion to which the output terminal of the pair of output terminals is fixed in the same direction as the input terminal of the input signal. 1. A circuit board for a surface wave filter element, comprising: