Patent US3989371A successfully refreshed from Google Patents.
US3671886A
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Method and apparatus for automatic gain control
Assignee: Fujitsu Ltd
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Filing: 1970-08-28
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Granted: 1972-06-20
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Expires: 1990-08-28
Abstract
Abstract Disclosed herein is automatic gain control circuitry for a transmission line of a PCM regenerative repeater, wherein such circuitry uses multistage variable equalizing networks. Each network has a variable reactance element, and has a predetermined pole frequency which is automatically varied under the control of its associated reactance element. The pole frequencies are changes in proportion to the square of a ratio of a standard line loss to a changed line loss due to the line loss variation, both measured in db. Thus, the pole frequency changes compensate for variation of the line loss.
Inventors
- 👤 Isao Fudemoto
- 👤 Tsutomu Yoshibayashi
- 👤 Tadao Miyamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:50
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/20; H03; H03G; H03G1/00; H03G1/0005; H03G1/0035; H03G1/0052; H03G1/0064; H03G3/00; H03G3/20; H03G3/30; H03G3/3036; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/06; H04R; H04R2225/00; H04R2225/43
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
123 words
A method for compensating for line losses in a transmission line comprising the steps of connecting a plurality of equalizing networks in cascade in a transmission line, each said network having a variable reactance element, and varying the reactance of each element to change the pole frequencies of said networks in proportion with the square of the ratio of a standard line loss to a changed line loss due to a line loss variation, the reactance of said elements is varied by the steps of detecting the output of said cascade connected networks, varying a DC control voltage in response to changes in said output, and applying said DC control voltage to each reactance element to change said pole frequencies of said networks.
Claim 2
Independent Claim
123 words
A method for compensating for line losses in a transmission line comprising the steps of connecting a plurality of equalizing networks in cascade in a transmission line, each said network having a variable reactance element, and varying the reactance of each element to change the pole frequencies of said networks in proportion with the square of the ratio of a standard line loss to a changed line loss due to a line loss variation, the reactance of said elements is varied by the steps of detecting the output of said cascade connected networks, varying a DC control voltage in response to changes in said output, and applying said DC control voltage to each reactance element to change said pole frequencies of said networks.
Claim 3
Dependent Claim
160 words
Automatic gain control circuitry for a transmission line comprising a transmission line, a plurality of variable equalizing networks connected in series, said series combination of networks having an input and an output connected in said transmission line, detector means connected to one of said equalizing networks for detecting an output signal thereof, control circuit means connecting said detector means to each of said equalizing networks for varying the pole frequencies of said plurality of networks according to the square of the ratio of a standard line loss to a changed line loss due to a line loss variation, said detector means comprising a peak value detector circuit for detecting line loss variations, said control circuit means comprising means for varying a DC control voltage in response to changes in said output signal detected by said peak value detector circuit, and said equalizing networks including variable reactance elements having said DC control voltage coupled thereto to vary said network pole frequencies.
Claim 4
Dependent Claim
160 words
Automatic gain control circuitry for a transmission line comprising a transmission line, a plurality of variable equalizing networks connected in series, said series combination of networks having an input and an output connected in said transmission line, detector means connected to one of said equalizing networks for detecting an output signal thereof, control circuit means connecting said detector means to each of said equalizing networks for varying the pole frequencies of said plurality of networks according to the square of the ratio of a standard line loss to a changed line loss due to a line loss variation, said detector means comprising a peak value detector circuit for detecting line loss variations, said control circuit means comprising means for varying a DC control voltage in response to changes in said output signal detected by said peak value detector circuit, and said equalizing networks including variable reactance elements having said DC control voltage coupled thereto to vary said network pole frequencies.
Claim 5
Dependent Claim
47 words
The invention as set forth in claim 2, in which each said equalizing network includes an amplifier and one of said variable reactance elements comprising a semiconductor capacitor, and in which each said semiconductor capacitor is coupled to said DC control voltage in said control circuit means.
Claim 6
Independent Claim
114 words
A method for compensating for line losses in a transmission line comprising the steps of connecting a plurality of equalizing networks in cascade in a transmission line, each said network having a variable reactance element, applying a DC control voltage derived from the transmission line to each element to vary the reactance of each said element to change the pole frequencies of said networks in proportion with the square of the ratio of a standard line loss to a changed line loss due to a line loss variation, and prior to varying the reactance of each said element deriving the DC control voltage varied in response to changes of an output of the networks.
Claim 7
Independent Claim
114 words
A method for compensating for line losses in a transmission line comprising the steps of connecting a plurality of equalizing networks in cascade in a transmission line, each said network having a variable reactance element, applying a DC control voltage derived from the transmission line to each element to vary the reactance of each said element to change the pole frequencies of said networks in proportion with the square of the ratio of a standard line loss to a changed line loss due to a line loss variation, and prior to varying the reactance of each said element deriving the DC control voltage varied in response to changes of an output of the networks.
Claim 8
Dependent Claim
48 words
A method for compensating for line losses in a transmission line as set forth in claim 4, in which the control voltage is derived by the steps of detecting the output of said cascade connected networks, varying a DC control voltage in response to changes in said output.
References Cited (Backward Citations)
US2719270A
Cited
US2805398A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |