JPH01233906A - Filter bank - Google Patents

Abstract

PURPOSE:To make the lateral width of the filter bank narrow and to attain miniaturization in comparison with a conventional filter bank by adopting two-stage structure for a package of the filter bank, containing a surface acoustic wave film to one stage and storing a distribution circuit to the other stage. CONSTITUTION:A partition plate 6 sections a package 3 into two stages vertically. A lead pin 7 is penetrated vertically to the partition plate 6. The surface acoustic wave filter 1 is stored in the lower stage sectioned by the partition plate 6 and the distribution circuit is stored on the upper stage. Both ends of a microstrip line 2b of the distribution circuit 2 are connected respectively to a signal input lead terminal 3a of the filter bank and a termination resistance connection lead terminal 3b. The input terminal 1a of each surface acoustic wave filter 1 is connected to the microstrip line 2b via the lead pin 7 and a lead wire 8. The output terminal 1b of each surface acoustic wave film 1 is connected to the output lead terminal 3c of the filter bank. A signal given to the filter bank is distributed to each surface acoustic wave filter 1 via the distribution circuit 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a filter bank consisting of a plurality of surface acoustic wave filters having different passing frequency bands.

[Conventional technology]

Figures 4(a) and (b) are, for example, Utility Model Kaikai 61-29.
4(a) is a plan view, and FIG. 4(0) is a sectional view taken along line A-AI in FIG. 4(a). In the figure, (
1) is a surface acoustic wave filter, (la) is an input terminal of the surface acoustic wave filter, and (1b) is an output terminal. (2) surrounded by a dotted line is a distribution circuit for distributing the input signal to each surface acoustic wave filter, for example, a distribution circuit formed on a dielectric substrate (z&) and a dielectric substrate (2a). The microstrip line (consists of two lines). The input terminal (la) of the surface acoustic wave filter (1) is connected to the microstrip line (2b). (3) is the surface acoustic wave filter (1). (3L) t (31)) + (
3C) are lead terminals provided on the package (3), and are respectively lead terminals for inputting a signal to the filter bank, for connecting a terminating resistor, and for outputting the filter bank. Lead terminal (3&) l (3b) is distribution circuit (2)
are connected to the tips of the microstrip lines (2b), respectively. Further, the lead terminal (30) is connected to the output terminal (1b) of the surface acoustic wave filter (1).

(4) is the upper pig. In addition, in FIG. 1(,), the upper lid (4) is shown removed for ease of viewing.

Next, the operation will be explained. For example, when an input signal of an unknown frequency is input to the filter bank through the lead terminal (3&), a human power signal is distributed to each surface acoustic wave filter (1) via the distribution circuit (2). Since each surface acoustic wave filter (1) has a different pass frequency band, the output signal level of only the lead terminal (30) corresponding to the frequency of the input signal is high. Therefore, by detecting which terminal of the lead terminal (3c) has the highest output level, the frequency of the input signal can be known. As shown in Figure 4, the seed filter bank consists of a surface acoustic wave filter (1) and a distribution circuit (2).
) are arranged in the same plane, the width becomes wide in FIG. 4, and when it is incorporated into a device for use, it may be difficult to store.

This invention was made to solve the above problems, and aims to obtain a small filter bank with a narrow width.

[Means to solve the problem]

The filter bank according to this invention is Nogutsu Cage (3).
The structure is made smaller by having a two-stage structure.

[Effect]

The filter bank in this invention consists of a nose cage (3
) has a two-stage structure, and one stage has a surface acoustic wave filter (1
), and the distribution circuit (2) is housed in the other stage, thereby achieving miniaturization.

[Embodiments of the invention]

Figures 1 (&) to (o) are diagrams showing one embodiment of the filter bank according to the present invention. Figure 1 (-) is a plan view, Figure 1 (b) is a bottom view, and Figure 1 (b) is a bottom view. Figure 1 (0) is Figure 1 (a)
It is an AA' cross-sectional view in . Figure 1 (IL), (b
), the upper lid (4) and lower lid (5) are removed for ease of viewing. In Figure 1,
(6) is a partition plate that partitions the package (3) into two levels, upper and lower. The partition υ board (6) has a lead bin (7)
It passes through the top and bottom. Since the package (3) and the partition plate (6) are usually made of metal, the lead bin (7) of the partition plate (6) is connected to the lead terminal (3) of the package (3).
Similar to a), (31)), and (30), it is manufactured using a so-called glass terminal in which only the vicinity of the lead bin (7) is made of glass. This will be explained in more detail using Figure 2. Figure 2 is a diagram showing only the partition plate (6), Figure 2 (&) is a plan view, and Figure 2 (b) is an AA sectional view in Figure 2 (&). o (6m) is a metal plate, and (7) beam-dopin% C6b') is glass. Since the glass (6b) is sandwiched between the lead bins (7) and the metal plate (6a), the lead bin (7) does not come into electrical contact with the metal plate (6a).
Note that it is preferable that the metal plate (6&) is at the same potential as the package (3) and electrically grounded.

In FIG. 1, (1) and (2) are a conventional surface acoustic wave filter and a distribution circuit, respectively. However, unlike the conventional surface acoustic wave filter (1), the package (3
) is housed in the lower stage separated by a partition plate (6), and the distribution circuit is housed in the upper stage. Distribution circuit (2)
The image tips of the IJ tube line (2b) are connected to the signal input lead terminal (3a) of the filter bank and the termination resistor connection lead terminal (3b), respectively, as in the conventional case. However, unlike in the past, the input terminal (1a) of each surface acoustic wave film (1) is connected to the lead bin (7).
, the microstrip line (2) via the lead wire (8).
b) is connected. The output terminal (1b) of each surface acoustic wave film (1) is connected to the output lead terminal (30) of the film bank, as in the conventional case.

In the film bank in the embodiment shown in FIG. 1, the signal input to the film bank is also sent to the distribution circuit (2)
is distributed to each surface acoustic wave film (1) through the. Therefore, as in the prior art, the frequency of the input signal can be determined by detecting which output level of each output lead terminal (3o) of the film bank is high.

However, in the filter bank according to the present invention, unlike the conventional filter bank, the surface acoustic wave film (1) is housed in the lower stage of the sensor cage (3), and the distribution circuit (2) is housed in the upper stage.
There is an advantage that the width of the package (3) can be narrower than in the past. The surface acoustic wave film (1) may be used in a packaged state, but if used in a chip state, the thickness of the chip of the surface acoustic wave film (1) is usually 0.
Furthermore, the thickness of the dielectric substrate (2&) of the distribution circuit (2) is usually less than 1 mm, so the thickness of the filter bank package (3) is the same or only slightly thicker than the conventional one. That's fine. Therefore, there is an advantage that the size can be reduced by narrowing the width compared to the conventional device.

FIG. 3 shows another embodiment of the invention.
FIG. 3(a) is a plan view, and FIG. 3(b) is a bottom view.

In FIG. 3, unlike in FIG. 1, a shield plate (9) made of metal is provided between each surface acoustic wave film (1). This has the advantage that electrical isolation can be improved and frequencies can be detected more accurately.
As shown at 32, a radio wave absorber may be provided in the empty display section in the notebook cage (3). If this is done, there is an advantage that the electrical isolation characteristics can be further improved.

Also, the lead terminals (3a) to (3c) of the package (3)
) in the package C3) is not limited to the positions shown in FIGS. 1 and 2. The position of the lead pin (7) is also similar. Further, the shape of the micro IJ tube line (2b) of the distribution circuit (2) is not limited to that shown in FIGS. 1 and 2.

〔Effect of the invention〕

As described above, according to the present invention, the filter bank package (3) has a two-stage structure, in which the surface acoustic wave film (1) is housed in one stage, and the distribution circuit (2) is housed in the other stage. Therefore, the filter bank has the advantage of being narrower in width and more compact than in the past.

[Brief explanation of the drawing]

FIG. 1 shows a filter bank according to an embodiment of the present invention, FIG. 2 shows a partition plate, FIG. 3 shows another embodiment of the invention, and FIG. 4 shows a conventional filter bank. FIG. In the figure, (1) is a surface acoustic wave filter, (2) is a distribution circuit, and (3) is a package. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] Consisting of a plurality of surface acoustic wave filters with different passing frequency bands, a distribution circuit that distributes an input signal to each of the surface acoustic wave filters, and a package that houses the plurality of surface acoustic wave filters and the distribution circuit. A filter bank characterized in that the package has a two-stage structure, the plurality of surface acoustic wave filters are housed in one stage, and the distribution circuit is housed in the other stage.