US4862103A
Expired / Lapsed
US
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Variable equalization system
Assignee: Hitachi Ltd
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Filing: 1988-11-17
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Granted: 1989-08-29
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Expires: 2008-11-17
Abstract
Abstract A variable equalization system is disclosed, in which a plurality of amplification cells having a plurality of filter groups with natural frequencies progressively increased four times are connected in series or in parallel, thereby making possible a variable equalization over a wide range of cable length.
Inventors
- 👤 Takashi Funada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:46
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/14; H04B3/141
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
157 words
A variable equalization system comprising: a plurality of first amplification cells, each including a variable gain amplifier with a flat frequency characteristic and a filter with a natural frequency of F 1 ; a plurality of second amplification cells twice more than the first amplification cells, and each including a variable gain amplifier of a flat frequency characteristic and a filter having a natural frequency F 2 four times higher than the natural frequency F 1 of the filters of the first amplification cells: and a plurality of third amplification cells twice the second amplification cells in number, each of the third amplification cells having a variable gain amplifier of a flat frequency characteristic and a filter of a natural frequency F 3 four times higher than the natural frequency F 2 of the filters of the second amplification cells, the first amplification cells, the second amplification cells and the third amplification cells being connected in series.
Claim 2
Dependent Claim
157 words
A variable equalization system comprising: a plurality of first amplification cells, each including a variable gain amplifier with a flat frequency characteristic and a filter with a natural frequency of F 1 ; a plurality of second amplification cells twice more than the first amplification cells, and each including a variable gain amplifier of a flat frequency characteristic and a filter having a natural frequency F 2 four times higher than the natural frequency F 1 of the filters of the first amplification cells: and a plurality of third amplification cells twice the second amplification cells in number, each of the third amplification cells having a variable gain amplifier of a flat frequency characteristic and a filter of a natural frequency F 3 four times higher than the natural frequency F 2 of the filters of the second amplification cells, the first amplification cells, the second amplification cells and the third amplification cells being connected in series.
Claim 3
Dependent Claim
17 words
A variable equalization system according to claim 1, wherein each of the filters is of high-pass type.
Claim 4
Dependent Claim
170 words
A variable equalization system comprising: a plurality of first amplification cells each including a variable gain amplifier of a flat frequency characteristic and a filter of a natural frequency F 1 ; a plurality of second amplification cells including amplification cells in series twice as many as the first amplification cells, each including a variable gain amplifier of a flat frequency characteristic and a filter of a natural frequency F 2 four times as high as the natural frequency F 1 of the filters of the first amplification cells; and a plurality of third amplification cells twice as many as the second amplification cells and connected in series, each of the third amplification cells including a variable gain amplifier of a flat frequency characteristic and a filter of a natural frequency F 3 four times higher than the natural frequency F 2 of the filters of the second amplification cells; the first amplification cells, the second amplification cells and the third amplification cells being connected in parallel to each other.
Claim 5
Dependent Claim
170 words
A variable equalization system comprising: a plurality of first amplification cells each including a variable gain amplifier of a flat frequency characteristic and a filter of a natural frequency F 1 ; a plurality of second amplification cells including amplification cells in series twice as many as the first amplification cells, each including a variable gain amplifier of a flat frequency characteristic and a filter of a natural frequency F 2 four times as high as the natural frequency F 1 of the filters of the first amplification cells; and a plurality of third amplification cells twice as many as the second amplification cells and connected in series, each of the third amplification cells including a variable gain amplifier of a flat frequency characteristic and a filter of a natural frequency F 3 four times higher than the natural frequency F 2 of the filters of the second amplification cells; the first amplification cells, the second amplification cells and the third amplification cells being connected in parallel to each other.
Claim 6
Dependent Claim
17 words
A variable equalization system according to claim 3, wherein each of the filters is a band-pass type.
References Cited (Backward Citations)
US2907838A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |