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US4841264A
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US
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Ladder-type ceramic filter
Assignee: Toko Inc
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Filing: 1988-07-19
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Granted: 1989-06-20
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Expires: 2008-07-19
Abstract
Abstract A ladder-type ceramic filter is formed of a plurality of series and parallel resonators arranged in series and in parallel between the input and output terminals. In this filter, a series resonator on the side of the input terminal has a resonant frequency lower than those of other series resonators and an antiresonant frequency higher than those of other series resonators. Further, a parallel resonator on the side of the output terminal has a resonant frequency lower than those of other parallel resonators and an antiresonant frequency higher than those of other parallel resonators.
Inventors
- 👤 Michitaka Oshikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 10:31
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/54; H03H9/58; H03H9/60; H03H9/605
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
164 words
A ladder type piezoelectric ceramic filter comprising an input terminal, an output terminal and a plurality of resonator sections connected between said input terminal and said output terminal, each section comprising a series resonance element and a parallel resonance element, the resonance frequency of a series resonance element provided in a section located closest to said input terminal being lower than the resonance frequency of series resonance elements provided in other sections, the antiresonance frequency of the series resonance element provided in said section located closest to said input terminal being higher than that of said series resonance elements provided in other sections, the resonance frequency of a parallel resonance element provided in a section located closest to said output terminal being lower than that of parallel resonance elements provided in other sections, and the antiresonance frequency of said parallel resonance element provided in said section located closest to said output terminal being higher than that of parallel resonance elements provided in other sections.
Claim 2
Dependent Claim
164 words
A ladder type piezoelectric ceramic filter comprising an input terminal, an output terminal and a plurality of resonator sections connected between said input terminal and said output terminal, each section comprising a series resonance element and a parallel resonance element, the resonance frequency of a series resonance element provided in a section located closest to said input terminal being lower than the resonance frequency of series resonance elements provided in other sections, the antiresonance frequency of the series resonance element provided in said section located closest to said input terminal being higher than that of said series resonance elements provided in other sections, the resonance frequency of a parallel resonance element provided in a section located closest to said output terminal being lower than that of parallel resonance elements provided in other sections, and the antiresonance frequency of said parallel resonance element provided in said section located closest to said output terminal being higher than that of parallel resonance elements provided in other sections.
Claim 3
Dependent Claim
86 words
A ladder type piezoelectric ceramic filter according to claim 1 comprising at least three of said sections and wherein all of the series resonance elements provided in the sections other than that located in said section located closest to said input terminal are provided with equal resonance frequencies and equal antiresonance frequencies, while all of the parallel resonance elements provided in said sections, other than that located in said section located closest to said output terminal are provided with equal resonance frequencies and equal antiresonance frequencies.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-19 | 1992-12-19 | 1993-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-19 | 1996-12-19 | 1997-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-19 | 2000-12-19 | 2001-06-20 | $7700.00 | Window Closed / Lapsed |