CN201294503Y - SAW filter - Google Patents
SAW filter Download PDFInfo
- Publication number
- CN201294503Y CN201294503Y CNU2008201653749U CN200820165374U CN201294503Y CN 201294503 Y CN201294503 Y CN 201294503Y CN U2008201653749 U CNU2008201653749 U CN U2008201653749U CN 200820165374 U CN200820165374 U CN 200820165374U CN 201294503 Y CN201294503 Y CN 201294503Y
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- interdigital transducer
- busbar
- solder joint
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- Expired - Lifetime
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- 239000000758 substrate Substances 0.000 claims abstract description 10
- 229910000679 solder Inorganic materials 0.000 claims description 33
- 238000010897 surface acoustic wave method Methods 0.000 claims description 22
- 101100190527 Arabidopsis thaliana PIN5 gene Proteins 0.000 claims description 6
- 101100190530 Arabidopsis thaliana PIN8 gene Proteins 0.000 claims description 6
- 108010059419 NIMA-Interacting Peptidylprolyl Isomerase Proteins 0.000 claims description 6
- 101150087393 PIN3 gene Proteins 0.000 claims description 6
- 108010037490 Peptidyl-Prolyl Cis-Trans Isomerase NIMA-Interacting 4 Proteins 0.000 claims description 6
- 102100026114 Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 Human genes 0.000 claims description 6
- 102100031653 Peptidyl-prolyl cis-trans isomerase NIMA-interacting 4 Human genes 0.000 claims description 6
- 102000007315 Telomeric Repeat Binding Protein 1 Human genes 0.000 claims description 6
- 108010033711 Telomeric Repeat Binding Protein 1 Proteins 0.000 claims description 6
- 229910002796 Si–Al Inorganic materials 0.000 claims description 3
- 238000000354 decomposition reaction Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Images
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- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
The utility model discloses an acoustic surface wave filter comprising a piezoelectric substrate, wherein an input interdigital transducer and an output interdigital transducer are arranged on the piezoelectric substrate along the transmitting direction of an acoustic surface wave, the input interdigital transducer comprises an upper, a middle and a lower weighting interdigital transducers which are parallel, the upper, the middle and the lower parallel weighting interdigital transducers share the same four omnibus bars, wherein an upper omnibus bar of the middle interdigital transducer and a lower omnibus bar of the lower interdigital transducer share the same omnibus bar L2, a lower omnibus bar of the middle interdigital transducer and an upper omnibus bar of the lower interdigital transducer share the same omnibus bar L3, both the upper omnibus bar L1 of the upper interdigital transducer and the lower omnibus bar L4 of the lower interdigital transducer are connected with a switching input pin, the omnibus bar L2 is connected to the signal input pin, and the omnibus bar L3 is earthed. The filter has the advantages of low cost and small volume. And the acoustic surface wave filter is mainly applied in a multi-standard television, and can realize the switching of different standards or bandwidths through a switch.
Description
Technical field
The utility model relates to a kind of Surface Acoustic Wave Filter, particularly relates to a kind of Surface Acoustic Wave Filter that can realize different systems or bandwidth switching by switch.
Background technology
Along with simulated television develops towards multi-modulation scheme, full system type pictorial direction, and the Digital Television that develops rapidly equally also need be switched between different bandwidth, sound surface wave TV IF filter is the throat of television set intermediate-frequency channel, relevant signals such as image, sound accompaniment, colour subcarrier all will be handled by it, therefore certainly will require surface acoustic wave can adapt to the signal processing of different systems.
The operation principle of Surface Acoustic Wave Filter is for adopting the planar technique of semiconductor integrated circuit, at piezoelectric substrate (lithium niobate, lithium tantalate) the certain thickness aluminium film of surperficial evaporation, again the mask pattern of the interdigital transducer (IDT) of two that design similar fingers intersections, utilize photoetching method to be deposited on substrate surface, be used separately as input transducer and output transducer, when signal is imported, the input transducer converts the electrical signal to acoustical signal, acoustical signal propagates into output transducer along plane of crystal, output transducer converts the acoustical signal that receives to signal of telecommunication output again, and signal is at the interdigital transducer electroacoustic, realize filter function in the process of acoustic-electric conversion.
Simulated television mainly contains NTSC at present, PAL, three kinds of standards of SECAM, it has different bandwidth requirements, and Digital Television also has 6MHz, 7MHz, the bandwidth that 8MHz is different, previous two different Surface Acoustic Wave Filter of function of TV employing realize the needs of different standard or bandwidth, so device volume is bigger, and cost is higher; Employing was placed on the Surface Acoustic Wave Filter chip of difference in functionality and realized above-mentioned handoff functionality in the same encapsulation again afterwards, but adopt above-mentioned specification requirement chip bigger, the input impedance that different systems or different bandwidth require differs greatly, and circuit designer's matching ratio is difficulty.
Summary of the invention
The utility model provides a kind of cost low at above-mentioned the deficiencies in the prior art, and volume is little, is mainly used in multi-system television machine intermediate frequency filtering, can realize the Surface Acoustic Wave Filter that different systems or bandwidth are switched by switch.
The technical solution of the utility model is achieved in that a kind of Surface Acoustic Wave Filter, comprise piezoelectric substrate, be provided with input interdigital transducer and output interdigital transducer in piezoelectric substrate upper edge acoustic surface wave propagation direction, between input interdigital transducer and output interdigital transducer, be provided with shielding strip, the input and output solder joint of input interdigital transducer and output interdigital transducer links to each other with the input and output pin of base by lead-in wire respectively, described output interdigital transducer is that the interdigital transducer by even constant amplitude constitutes, and the input interdigital transducer is by last, in, following three parallel weighting interdigital transducers constitute; Three the parallel weighting interdigital transducers in described upper, middle and lower are shared and are used 4 busbars, the following busbar of the last busbar of interdigital transducer and last interdigital transducer is shared and is used same busbar L2 wherein, and the following busbar of middle interdigital transducer is shared with the last busbar of following interdigital transducer and used same busbar L3; The last busbar L1 of last interdigital transducer and the following busbar L4 of following interdigital transducer all are connected to the switch input pin, and busbar L2 is connected to signal input pin, busbar L3 ground connection.
As preferably, the weighted amplitude of middle interdigital transducer is greater than the weighted amplitude of upper and lower two interdigital transducers.
As preferably, the last busbar L1 of last interdigital transducer and the following busbar L4 of following interdigital transducer all are connected to solder joint PIN2, busbar L2 is connected to solder joint PIN1, busbar L3 is connected with shielding strip, shielding strip is connected to solder joint PIN3, and described solder joint PIN1, solder joint PIN2 and solder joint PIN3 are connected to signal input pin, switch input pin and grounding leg on the base by lead-in wire respectively; The last busbar of output interdigital transducer 2 and following busbar are connected respectively to solder joint PIN5, solder joint PIN4, and described solder joint PIN5 and solder joint PIN4 are connected to two parallel signal output pins on the base by lead-in wire respectively.
As preferably, described lead-in wire is a Si-Al wire.
Adopted the advantage that the utlity model has of technique scheme to be:
One, the input interdigital transducer of this Surface Acoustic Wave Filter is to be made of three parallel weighting interdigital transducers, and these three transducers adopt the finger windowed overlapping, can decide by the switching of switch input pin superposes by last interdigital transducer and the stack of middle interdigital transducer or by middle interdigital transducer and following interdigital transducer realizes switching between the different frequency response bandwidth, therefore switch more convenient, simple and practical;
Two, the identical function the realized Surface Acoustic Wave Filter before comparing, volume is smaller and more exquisite, and greatly reduces cost.
Description of drawings
Fig. 1 is a planar structure schematic diagram of the present utility model;
Fig. 2 is the sectional view in kind of input interdigital transducer in the utility model;
Fig. 3 is the utility model embodiment decomposition frequency response sketch to required frequency response in simulated television is used, wherein FBG, FM are required frequency response sketch, A, B, C are the corresponding frequency response sketch that decomposes, the frequency response that A, B, C are obtained by interdigital transducer CH1, CH2, CH3 transmission output transducer respectively;
Fig. 4 is the utility model embodiment decomposition frequency response sketch to required frequency response in digital television application, wherein F8, F7 are required frequency response sketch, A, B, C are the corresponding frequency response sketch that decomposes, and A, B, C are transferred to the frequency response that output transducer obtains by CH1, CH2, CH3 among Fig. 1 respectively;
Fig. 5 is the practical frequency response curve by the switchable Surface Acoustic Wave Filter of a Digital Television intermediate frequency dedicated bandwidth of the technical solution of the utility model making.
Embodiment
Embodiment of the present utility model is as follows:
Embodiment: a kind of Surface Acoustic Wave Filter, comprise piezoelectric substrate, be provided with input interdigital transducer and output interdigital transducer 2 in piezoelectric substrate 1 upper edge acoustic surface wave propagation direction, be provided with shielding strip 3 between input interdigital transducer and output interdigital transducer 2, the input and output solder joint of input interdigital transducer and output interdigital transducer 2 links to each other with the input and output pin of base by lead-in wire respectively.
As shown in Figure 1, the right-hand component of shielding strip 3 is output interdigital transducers 2, and described output interdigital transducer 2 is made of interdigital interdigital transducer of forming of one group of even constant amplitude; Shielding strip left-hand component is the input interdigital transducer, the input interdigital transducer is to be made of three the parallel weighting interdigital transducers in upper, middle and lower, these three interdigital transducers all are finger windowed overlappings, the weighted amplitude of simply having represented the three among Fig. 1 respectively, wherein the weighted amplitude of middle interdigital transducer CH2 is far longer than the weighted amplitude of interdigital transducer CH1 and following interdigital transducer CH3; Therefore interdigital transducer CH2 is a main transducer in the middle of, and very approaching on the finger windowed overlapping of last interdigital transducer CH1 and following interdigital transducer CH3, weighted amplitude is less, therefore is the compensation transducer.
As shown in Figure 1 and Figure 2, three the parallel weighting interdigital transducers in described upper, middle and lower are shared and are used 4 busbars, the following busbar of the last busbar of interdigital transducer CH2 and last interdigital transducer CH1 is shared and is used same busbar L2 wherein, and the following busbar of middle interdigital transducer CH2 is shared with the last busbar of following interdigital transducer CH3 and used same busbar L3.
The last busbar L1 of last interdigital transducer CH1 and the following busbar L4 of following interdigital transducer CH3 all are connected to solder joint PIN2, busbar L2 is connected to solder joint PIN1, busbar L3 is connected with shielding strip 3, shielding strip 3 is connected to solder joint PIN3, and described solder joint PIN1, solder joint PIN2 and solder joint PIN3 are connected to signal input pin T1, switch input pin T2 and grounding leg T3 on the base by lead-in wire respectively; The last busbar L5 of output interdigital transducer 2 and following busbar L6 are connected respectively to solder joint PIN5, solder joint PIN4, and described solder joint PIN5 and solder joint PIN4 are connected to parallel signal output pin T5 and signal output pin T4 on the base by lead-in wire respectively.Described lead-in wire adopts Si-Al wire.
When switch input pin T2 ground connection, busbar L1 and busbar L4 ground connection, and busbar L3 is by shielding strip 3 ground connection, the last busbar L3 of following interdigital transducer CH3 and following busbar L4 are zero potentials, so can not produce inverse piezoelectric effect, promptly descend not work of interdigital transducer CH3, have only last interdigital transducer CH1 and middle interdigital transducer CH2 work; When switch input pin T2 and signal input pin T1 equipotential, be the signal input pin T1 that switch input pin T2 is connected to the signal input, the last busbar L1 and the following busbar L2 that go up transducer CH1 so import as signal simultaneously, both equipotentials, last interdigital transducer CH1 does not work, and has only middle interdigital transducer CH2 and following interdigital transducer CH3 work.No matter interdigital transducer CH2 and following interdigital transducer CH3 work in the middle of last interdigital transducer CH1 and the middle interdigital transducer CH2 work still, under the two states both impedances very approaching, it is very favorable like this circuitry designer being mated.
The course of work to Surface Acoustic Wave Filter of the present utility model is illustrated below, the video bandwidth of B/G system is 5MHz in the standard of simulated television, and the video bandwidth of M system is 4MHz, when Surface Acoustic Wave Filter requires B/G to take into account the M system, can between 5MHz and 4MHz, switch by switch input pin T2 like this, FBG and FM are two switchable frequency response sketches that finally will obtain among Fig. 3, can know that by analyzing these two frequency responses can obtain A among Fig. 3 by decomposition, B, three frequency response sketches of C, wherein the bandwidth of B is 4.5MHz, A, the bandwidth of C all is 0.5MHz, amplitude is more half as large than B, and amplitude is just in time opposite between A and the C, so A and B stack obtains the pairing 5MHz bandwidth of BG system frequency response FBG, B and C stack obtain the 4MHz bandwidth frequency response FM of M system, in the corresponding diagram 1, when design by on interdigital transducer CH1 weighting design make the frequency response of its output satisfy frequency response A requirement among Fig. 3, satisfy frequency response B requirement among Fig. 3 by middle interdigital transducer CH2 weighting design being made the frequency response of its output, by following interdigital transducer CH3 weighting design being made the frequency response of its output satisfy frequency response C requirement among Fig. 3, switch by switch input T2 pin again and decide A and B stack or B and C to reach the switching of the requirement of different frequency response bandwidth.
Equally in the Digital Television intermediate-frequency filter, if requiring Surface Acoustic Wave Filter can satisfy between 8MHz and 6MHz switches, the frequency response of corresponding frequency response that requires and decomposition as shown in Figure 4, F8, two frequency responses of F7 for finally obtaining, A, B, C is corresponding decomposition frequency response, in like manner if when design by interdigital transducer CH1 in to Fig. 1, middle interdigital transducer CH2, the weighting design of following interdigital transducer CH3 makes frequency response satisfy A, B, the switching requirement that just can reach 8MHz, 6MHz bandwidth is switched in the requirement of C by switch input pin T2.
Surface Acoustic Wave Filter of the present utility model, its centre frequency are 36MHz, and three dB bandwidth is switched at 7.4MHz and 6.4MHz, and output interdigital transducer adopts not weighted transducer, refers to that logarithm is 7 pairs, and centre frequency is 35.87MHz, and the aperture is 1.3mm; The input interdigital transducer adopts and refers to long windowed overlapping, the sampling frequency of three parallel interdigital transducers all is 36.13MHz, the finger number all is 267, last interdigital transducer CH1, the aperture of middle interdigital transducer CH2 and following interdigital transducer CH3 is respectively 0.2mm, 0.8mm, 0.2mm, the distance of input interdigital transducer and output interdigital transducer is got 0.6mm, the graphics area that obtains is 9.7mm * 1.8mm, area of chip is 11mm * 2.05mm, and the thickness of aluminium film is 5000 dusts in the making, and Fig. 5 is the actual measurement frequency response curve figure of Surface Acoustic Wave Filter of the present utility model on network analyzer, A is that three dB bandwidth is the passage frequency response curve of 7.4MHz among Fig. 5, B is that three dB bandwidth is the passage frequency response curve of 6.4MHz, by tracing analysis, learns that bandwidth meets the demands, band is outer to be suppressed at below the 30dB, satisfies the digital television application requirement.
Claims (4)
1, a kind of Surface Acoustic Wave Filter, comprise piezoelectric substrate, be provided with input interdigital transducer and output interdigital transducer (2) in piezoelectric substrate (1) upper edge acoustic surface wave propagation direction, between input interdigital transducer and output interdigital transducer (2), be provided with shielding strip (3), the input and output solder joint of input interdigital transducer and output interdigital transducer (2) links to each other with the input and output pin of base by lead-in wire respectively, it is characterized in that: described output interdigital transducer is that the interdigital transducer by even constant amplitude constitutes, the input interdigital transducer is by last, in, following three parallel weighting interdigital transducer (CH1, CH2 CH3) constitutes; Three the parallel weighting interdigital transducer (CH1 in described upper, middle and lower, CH2, CH3) share 4 busbars of use, the following busbar of the last busbar of interdigital transducer (CH2) and last interdigital transducer (CH1) is shared and is used same busbar (L2) wherein, and the following busbar of middle interdigital transducer (CH2) is shared with the last busbar of following interdigital transducer (CH3) and used same busbar (L3); The last busbar (L1) of last interdigital transducer (CH1) and the following busbar (L4) of following interdigital transducer (CH3) all are connected to switch input pin (T2), and busbar (L2) is connected to signal input pin (T1), busbar (L3) ground connection.
2, Surface Acoustic Wave Filter according to claim 1 is characterized in that: the weighted amplitude of middle interdigital transducer (CH2) is greater than upper and lower two interdigital transducers (CH1, weighted amplitude CH3).
3, Surface Acoustic Wave Filter according to claim 1, it is characterized in that: go up the last busbar (L1) of interdigital transducer (CH1) and the following busbar (L4) of following interdigital transducer (CH3) and all be connected to solder joint (PIN2), busbar (L2) is connected to solder joint (PIN1), busbar (L3) is connected with shielding strip (3), shielding strip (3) is connected to solder joint (PIN3), and described solder joint (PIN1), solder joint (PIN2) and solder joint (PIN3) are connected to signal input pin (T1), switch input pin (T2) and grounding leg (T3) on the base by lead-in wire respectively; The last busbar (L5) of output interdigital transducer (2) and following busbar (L6) are connected respectively to solder joint (PIN5), solder joint (PIN4), described solder joint (PIN5) and solder joint (PIN4) respectively by lead-in wire be connected to signal output pin on the base (T5, T4).
4, Surface Acoustic Wave Filter according to claim 3 is characterized in that: described lead-in wire is a Si-Al wire.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201653749U CN201294503Y (en) | 2008-09-27 | 2008-09-27 | SAW filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201653749U CN201294503Y (en) | 2008-09-27 | 2008-09-27 | SAW filter |
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| Publication Number | Publication Date |
|---|---|
| CN201294503Y true CN201294503Y (en) | 2009-08-19 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008201653749U Expired - Lifetime CN201294503Y (en) | 2008-09-27 | 2008-09-27 | SAW filter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108173773A (en) * | 2017-12-28 | 2018-06-15 | 深圳市安鼎信息技术有限公司 | 10000000000 network shunt devices |
-
2008
- 2008-09-27 CN CNU2008201653749U patent/CN201294503Y/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108173773A (en) * | 2017-12-28 | 2018-06-15 | 深圳市安鼎信息技术有限公司 | 10000000000 network shunt devices |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20090819 Effective date of abandoning: 20080927 |