CN2323517Y - VHF high band radio frequency surface acoustic wave filter - Google Patents
VHF high band radio frequency surface acoustic wave filter Download PDFInfo
- Publication number
- CN2323517Y CN2323517Y CN 97249148 CN97249148U CN2323517Y CN 2323517 Y CN2323517 Y CN 2323517Y CN 97249148 CN97249148 CN 97249148 CN 97249148 U CN97249148 U CN 97249148U CN 2323517 Y CN2323517 Y CN 2323517Y
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- weighted
- acoustic wave
- surface acoustic
- wave filter
- radio frequency
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Abstract
The utility model relates to a surface acoustic wave filter used at the front end of the adjacent frequency of a cable television for the very high frequency high band radio frequency treatment. The utility model adopts piezoelectric crystal Y112 DEG lithium tantalate as a base sheet and is composed of two transducers and a shielding bar. The weighting of the transducers can adopt single weighting (the combination of a non-weighted and a withdrawal weighted transducers or a non-weighted and an apodization weighted transducers) or can adopt double weighting (the combination of a withdrawal weighted and an apodization weighted transducers). The performance indication of the utility model is obviously superior to that of past inductance-capacitance filters and helical filters.
Description
The utility model relates to a kind of high section of very high frequency(VHF) radio frequency processing Surface Acoustic Wave Filter that is used for the adjacent front end frequently of cable TV.
The adjacent front end system frequently of cable TV divides two big classes: intermediate frequency process front end and radio frequency processing front end.The choke-condenser filter or the screw-filter of radio frequency processing front end use in the past because performance index are poor, regulate shortcomings such as complexity, consistency of product and poor stability, more and more can not satisfy the requirement of front end manufacturer large-scale production.
The purpose of this utility model is to propose a kind of high section of very high frequency(VHF) radio frequency Surface Acoustic Wave Filter of being made up of transducer and shielding strip, it has that passband fluctuation is little, band outer suppresses high, Group Delay Ripple is little and need adjustment, high conformity, characteristics such as reliable and stable, thereby solved the existing in prior technology problem.
The technical scheme that the utility model adopted is: it is by being made up of two transducers and shielding strip on the piezoelectric chip, said transducer and shielding strip are by the aluminium film that is plated on the piezoelectric chip, make through semiconductor planar technology, its input and output electrode by the lead-in wire with base with the signal input and output, single weighting is adopted in the weighting of transducer, that is: non-weighted sum withdrawal weighted transducer or non-weighted sum are cut and are referred to the weighted transducer combination, or two weightings, that is: withdraw-weighted and the compound mode of cutting the finger weighted transducer.
The high section of very high frequency(VHF) in cable TV radio frequency processing Surface Acoustic Wave Filter (comprises and augments 1 channel～augment, 7 channels, TV 6 channels are to～12 channels, augment 8 channels～augment, 11 channels) filter, because band connection frequency higher (112.25～254.75 megahertz), relative bandwidth narrower (less than 5%), be the frequency drift that reduces to cause because of variations in temperature, can only adopt the piezoelectric Y112 ° lithium tantalate of low-temperature coefficient, and the acoustic-electric coupling coefficient of Y112 ° of lithium tantalate is lower, be not suitable for the use of multistrip coupler, thereby can adopt single weighting (non-weighted sum withdrawal weighted transducer, non-weighted sum is cut the combination that refers to weighted transducer) or two weighting (withdraw-weighted and the combination of cutting the finger weighted transducer) mode.
Radio frequency processing Surface Acoustic Wave Filter in the utility model ,-1dB bandwidth are 6.5 megahertzes, and the squareness factor of device is less than 1.5, and passband fluctuation is less than 1dB, and band is outer to be suppressed greater than 35dB, and Group Delay Ripple is less than 60ns.The performance index of device are better than traditional choke-condenser filter and screw-filter.
Advantage of the present utility model is that volume is little, in light weight, compare with traditional choke-condenser filter, screw-filter, have that group delay characteristic preferably, less passband fluctuation, higher band are outer to be suppressed and produce good reproducibility, need not to adjust and advantage that temperature stability is good, especially be fit to large-scale mass production.
Fig. 1 is the part section structural representation of the utility model embodiment.
Fig. 2 is the chip structure schematic diagram among Fig. 1.
Fig. 3 is the amplitude-frequency response of Fig. 2 embodiment.
Below in conjunction with accompanying drawing the utility model preferred embodiment is described further.
As shown in Figure 1, it is the structural representation that is used for the high section of the very high frequency(VHF) radio frequency processing Surface Acoustic Wave Filter embodiment of the adjacent front end frequently of cable TV, two transducers 6,7 and the shielding strip 8 of the utility model on chip 2 formed, be by the aluminium film that is plated in piezoelectric chip, make through semiconductor planar technology, Surface Acoustic Wave Filter chip 2 is bonded on the base 1, and it inputs or outputs electrode and links to each other with pin 4 by lead-in wire 3, as depicted in figs. 1 and 2.
Fig. 2 is the structural representation of 10 channel Surface Acoustic Wave Filter chips 2 among Fig. 1 embodiment.By two transducers 6 on the Y112 ° of lithium tantanate substrate 5 and 7 and shielding strip 8 form.Transducer 6 weightings all take to cut the finger weighting, and length is 230 λ, transducer 7 not weightings, and length is 39.5 λ, and finger width and interval are λ/8, and width is 40 λ.Shielding strip 8 length are 30 λ, and width is 40 λ.
The squareness factor of the utility model device is less than 1.5, and passband fluctuation is less than 1dB, and band is outer to be suppressed greater than 35dB.The amplitude-frequency response of present embodiment, as shown in Figure 3.
Claims (4)
1. the high section of very high frequency(VHF) radio frequency Surface Acoustic Wave Filter.It is characterized in that it is made up of two transducers and shielding strip on piezoelectric substrate, its input and output electrode by the lead-in wire with base with the signal input and output.
2. according to the high section of the said very high frequency(VHF) of claim 1 radio frequency Surface Acoustic Wave Filter, it is characterized in that the weighting of transducer can be adopted single weighting or two weighting scheme.
3. according to the high section of the said very high frequency(VHF) of claim 2 radio frequency Surface Acoustic Wave Filter, it is characterized in that said single weighting, it is that non-weighted sum withdrawal weighted transducer, non-weighted sum are cut the combination that refers to weighted transducer.
4. according to the high section of the said very high frequency(VHF) of claim 2 radio frequency Surface Acoustic Wave Filter, it is characterized in that said pair of weighting, it is withdraw-weighted and cuts the combination that refers to weighted transducer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 97249148 CN2323517Y (en) | 1997-12-31 | 1997-12-31 | VHF high band radio frequency surface acoustic wave filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 97249148 CN2323517Y (en) | 1997-12-31 | 1997-12-31 | VHF high band radio frequency surface acoustic wave filter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2323517Y true CN2323517Y (en) | 1999-06-09 |
Family
ID=33956135
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 97249148 Expired - Fee Related CN2323517Y (en) | 1997-12-31 | 1997-12-31 | VHF high band radio frequency surface acoustic wave filter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2323517Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101316099B (en) * | 2008-07-04 | 2010-06-16 | 无锡市好达电子有限公司 | Double-channel SAW filter |
-
1997
- 1997-12-31 CN CN 97249148 patent/CN2323517Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101316099B (en) * | 2008-07-04 | 2010-06-16 | 无锡市好达电子有限公司 | Double-channel SAW filter |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |