Patent US4910481A successfully refreshed from Google Patents.
US4910481A
Expired / Lapsed
US
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Branching filter
Assignee: Kokusai Denki Electric Inc
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Filing: 1988-12-12
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Granted: 1990-03-20
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Expires: 2008-12-12
Abstract
Abstract A branching filter for separating or combining two different frequencies without interference in radio communication equipment etc. One or both of two filter blocks for separating or combining two signal waves whose central frequency differ from each other are constructed from a dielectric bandpass filter which allows the desired wave of a block to pass and a SAW band stop filter being connected in series with said filter which allows the desired wave of a block to pass and stops passing of the desired wave of another block.
Inventors
- 👤 Kanemi Sasaki
- 👤 Sadao Ogawa
- 👤 Mikio Takano
- 👤 Kennzo Urabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:10
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/38; H04B1/40; H04B1/50; H04B1/52
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
93 words
A branching filter for radio communication equipment having a plurality of branches for separating or combining combinations of transmitted or received signals having center frequencies which differ from one another; each branch of said branching filter comprising a di-electric bandpass filter in series with a SAW band-stop filter; said di-electric bandpass filter and SAW band-stop filter constructed to pass a desired waveform while blocking desired waveforms of the other branches of said branching filter whereby said branching filter system may be kept as small as possible for use in mobile radio communications systems.
Claim 2
Dependent Claim
93 words
A branching filter for radio communication equipment having a plurality of branches for separating or combining combinations of transmitted or received signals having center frequencies which differ from one another; each branch of said branching filter comprising a di-electric bandpass filter in series with a SAW band-stop filter; said di-electric bandpass filter and SAW band-stop filter constructed to pass a desired waveform while blocking desired waveforms of the other branches of said branching filter whereby said branching filter system may be kept as small as possible for use in mobile radio communications systems.
Claim 3
Dependent Claim
29 words
The branching filter according to claim 1 wherein said filter branches are signal transmission filter branches whereby multiple transmission signals may be processed and transmitted by said branching filter.
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) | 1993-03-19 | 1993-09-18 | 1994-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-19 | 1997-09-18 | 1998-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-19 | 2001-09-18 | 2002-03-20 | $7700.00 | Window Closed / Lapsed |