CN201667641U

CN201667641U - Combined-type two-channel surface acoustic wave filter

Info

Publication number: CN201667641U
Application number: CN2009200438928U
Authority: CN
Inventors: 沈丰其; 曹征祥
Original assignee: WUXI YANGXIAN ELECTRON Co Ltd
Current assignee: WUXI YANGXIAN ELECTRON Co Ltd
Priority date: 2009-05-26
Filing date: 2009-05-26
Publication date: 2010-12-08
Anticipated expiration: 2019-05-26

Abstract

The utility model discloses a combined-type two-channel surface acoustic wave filter. An interdigital transducer C1 and an interdigital transducer C2 are arranged at the input end of a piezoelectric substrate and a shared interdigital transducer D is arranged at the output end of the piezoelectric substrate. A grounded shielding strip G is arranged between the two interdigital transducers at the input end and the interdigital transducer at the output end. The shared interdigital transducer D is an interdigital transducer with equal-length fingers. The two interdigital transducers at the input end share one bus bar H2 which can be linear, zigzag or oblique-line-shaped, and shares one electrode P1 which is connected with an external terminal pin. The grounded shielding strip G is connected with the bus bar H3 of the two-channel interdigital transducer and shares one electrode P3. The utility model realizes functions of different systems or bandwidths through the change-over switch of an external circuit, can process television signals of different systems or bandwidths, and has the advantages that the consumed substrate materials are reduced, the manufacturing cost is reduced and the popularization value is very great.

Description

A kind of combined double-channel surface acoustic wave filter

Technical field

The utility model patent relates to a kind of double-channel SAW filter, relates in particular to a kind ofly can realize the different standards or the Surface Acoustic Wave Filter of bandwidth capability by diverter switch.

Background technology:

Surface Acoustic Wave Filter is the critical elements of television set intermediate-frequency channel, the groundwork principle is to utilize the piezoelectric property of piezoelectric, utilize input and output interdigital transducer to convert the input signal of electric wave to mechanical energy, after treatment, again mechanical energy is converted to the signal of telecommunication, to reach the purpose of unnecessary signal of filtration and noise, lifting reception quality.

The world simulation television system mainly contains PAL, SECAM, three kinds of standards of NTSC, and different standards has different bandwidth requirements.And emerging Digital Television has ATSC, DVB, ISDB standard, to each standard wherein, can be divided into satellite transmits, 3 kinds of different modes of cable transmission and terrestrial transmission again, different bandwidth requirements is equally also arranged between different standards, usually used two different acoustic surface wave filter devices of bandwidth to handle the signal of different systems respectively in the past, use the different acoustic surface wave filter device of two bandwidth not only on the television set wiring board area occupied bigger, and cost is also higher.

And along with recent years television set overall dimension towards ultra-thin direction develop, the integrated and price competition of height of mainboard, each manufacturer is in order to dwindle the mainboard size, to reduce the cost, also to take into account requirement, therefore preferably can use an intermediate frequency acoustic surface wave filter device just can handle the signal of different systems image, Television Sound Quality.

Summary of the invention:

The utility model patent provides a kind of and has been integrated on the piezoelectric crystal substrate at above the deficiencies in the prior art, just can handle the combined double-channel surface acoustic wave filter of the TV signal of different standards or bandwidth.

For realizing the above object, the technical scheme that the utility model patent adopts is as follows:

A kind of combined double-channel surface acoustic wave filter, wherein input is provided with two interdigital transducer C1, C2 on the piezoelectric substrate, output is provided with a shared interdigital transducer D, is provided with earth shield bar G between two interdigital transducers of input and the output interdigital transducer.

Described shared interdigital transducer D refers to the type interdigital transducer for waiting.

The shared busbar H2 of two interdigital transducers of described input, its shared busbar H2 can be that linear also can be complications or oblique line shape, and a shared electrode P1 links to each other with the outer lead pin.

Described earth shield bar G links to each other with the busbar H3 of two passage interdigital transducer C2, and a shared electrode P3.

The shared interdigital transducer D of described output is provided with output electrode P4, P5.

The busbar H1 of described input interdigital transducer C1 is connected with the diverter switch of external circuit by electrode P2.

In two input interdigital transducers of the utility model patent, the busbar H2 of input interdigital transducer C2 connects input electrical signal, busbar H3 is connected with earth shield bar G, and is in running order all the time; The busbar H1 of input interdigital transducer C1 is connected with the diverter switch of external circuit by electrode P2, according to the standard of processing signals or the needs of bandwidth capability busbar H1 is connected with input signal electrode P1 or earth shield bar G respectively, makes input interdigital transducer C1 be in work or off position; So just can realize the TV signal of an acoustic surface wave filter device processing different systems or bandwidth, effectively reduce the consumption of substrate material, lower manufacturing cost.

Description of drawings:

Fig. 1 is the utility model patent planar structure sketch;

Fig. 2 is the utility model patent planar structure detail drawing;

Fig. 3 is a passage practical frequency response diagram (Surface Acoustic Wave Filter of three dB bandwidth 8MHz) of the utility model patent working example;

Fig. 4 is two passage practical frequency response diagrams (Surface Acoustic Wave Filter of three dB bandwidth 7MHz) of the utility model patent working example;

Embodiment:

As shown in Figure 1 and Figure 2, a kind of combined double-channel surface acoustic wave filter, wherein piezoelectric substrate N goes up input and is provided with a passage interdigital transducer C1, two passage interdigital transducer C2, output is provided with a shared interdigital transducer D, is provided with earth shield bar G between input two interdigital transducer C1, C2 and the output interdigital transducer D.Wherein input one passage interdigital transducer C1 and the shared busbar H2 of input two passage interdigital transducer C2, the earth shield bar G between the input/output terminal links to each other with the busbar H3 of two passage interdigital transducer C2, and a shared electrode P3.

When the signal of telecommunication inserts input one passage interdigital transducer C1 by input electrode P1, make electrode P2, P3 ground connection simultaneously by diverter switch, have different current potential with busbar H1, H2 that input one passage interdigital transducer C1 links to each other this moment, input one passage interdigital transducer C1 promptly excites surface acoustic wave, and is in running order; Busbar H2, the H3 of input two passage interdigital transducer C2 also have different current potentials simultaneously, and excite surface acoustic wave, make it in running order; The shared finger transducer D such as output of two passages accept the surface acoustic wave from input interdigital transducer C1, C2, and convert the signal of telecommunication to and export through output electrode P4, P5, so just finish the filter function of first passage, a passage practical frequency response diagram as shown in Figure 3.

The busbar H3 of input two passage interdigital transducer C2 links to each other with earth shield bar G, when the signal of telecommunication inserts busbar H1, H2 by diverter switch simultaneously through electrode P1, P2, busbar H1, H2 have identical current potential at this moment, input one passage interdigital transducer C1 does not just excite surface acoustic wave, is in off position; And busbar H2, H3 have different current potentials at this moment, input two passage interdigital transducer C2 promptly excite surface acoustic wave, in running order, the shared finger transducer D such as output of two passages accept the surface acoustic wave from input two passage interdigital transducer C2, and convert the signal of telecommunication to and export through output electrode P4, P5, so just finish the filter function of second channel, the response of two passage practical frequencies is shown in Figure 4.

The utility model patent makes a combined double-channel surface acoustic wave filter just can realize different standards or bandwidth capability by the diverter switch of external circuit, diverter switch connects input signal and ground connection respectively, make two input interdigital transducers be in work or off position respectively by its switching, so just can handle the different standards or the TV signal of bandwidth, has the consumption that has reduced substrate material, lower manufacture cost and other advantages, have great promotional value.

Claims

1. combined double-channel surface acoustic wave filter, it is characterized in that: input is provided with two interdigital transducers (C1), (C2) on the described piezoelectric substrate, output is provided with a shared interdigital transducer (D), is provided with earth shield bar (G) between two interdigital transducers of input and the output interdigital transducer.

2. a kind of combined double-channel surface acoustic wave filter according to claim 1 is characterized in that: described shared interdigital transducer (D) refers to the type interdigital transducer for waiting.

3. a kind of combined double-channel surface acoustic wave filter according to claim 1, it is characterized in that: two shared busbars of interdigital transducer of described input (H2), its shared busbar (H2) can be that linear also can be complications or oblique line shape, and a shared electrode (P1) links to each other with the outer lead pin, earth shield bar (G) links to each other with the busbar (H3) of two passage interdigital transducers (C2), and a shared electrode (P3).