Title:
COMB-LIKE ELECTRODE FOR SURFACE ACOUSTIC WAVE FILTER
Document Type and Number:
Japanese Patent JP3170955
Kind Code:
B2
Abstract:
PURPOSE: To increase the impedance without degrading the extent of out-band attenuation and to reduce TTE to reduce the intra-band ripple by subjecting the impulse train obtained by inverse Fourier transformation to 2-fold oversampling to form another impulse train and periodically eliminating this formed impulse train and using the response having a frequency f0 generated by this elimination.
CONSTITUTION: A desired transmission characteristic (center frequency f0 and surface wave wavelength λ0) is subjected to inverse Fourier transformation to generate a first impulse train, and this first impulse train is subjected to two-fold over-sampling along its envelope with a 1/2 period to generate a second impulse train, and this second impulse train is divided into four impulse trains, and second and third impulses out of these four impulse trains are eliminated to generate a third impulse train, and IDT electrodes 4a to 4d are constituted in a piezoelectric substrate with this third impulse train.
Inventors:
Toru Watanabe
Application Number:
JP12697993A
Publication Date:
May 28, 2001
Filing Date:
May 28, 1993
Export Citation:
Assignee:
MURATA MANUFACTURING CO.,LTD.
International Classes:
H03H9/145; (IPC1-7): H03H9/145
Domestic Patent References:
| JP1225211A | ||||
| JP50126351A | ||||
| JP61164317A |
Other References:
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ＩＥＥＥ ＴＲＡＮＳＡＣＴＩＯＮＳ ＯＮ ＳＯＮＩＣＳ ＡＮＤ ＵＬＴＡＳＯＮＩＣＳ，ＶＯＬ．ＳＵ−２２，ＮＯ．６，ＮＯＶＥＭＢＥＲ １９７５，ｐ．３９５−４０１
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