US3737774A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic level control device for use in telecommunication systems
Assignee: Koninklijke Philips NV
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Filing: 1970-10-06
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Granted: 1973-06-05
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Expires: 1990-10-06
Abstract
Abstract Automatic level control device for use in telecommunication systems, said device comprising a level control member formed by a current-dependent impedance varying with the level control signal, said device comprising, in order to enable a very accurate adjustment of the level control signal, furthermore a variable current-independent impedance controlled by the level control signal, which together with the said current-dependent impedance forms part of a Wheatstone bridge formed by two parallel impedance circuits, of a variable direct-current source connected to said bridge and of a comparison device included in the galvanometer branch of the bridge, the output signal of said comparison device controlling the direct-current source.
Inventors
- 👤 J Verhagen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:01
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/04; H04B3/10; H04B3/12
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
155 words
A circuit comprising a repeater station adapted to be controlled by a control signal, said station comprising an amplifier having an input and an output, a wheatstone bridge circuit comprising a current independent controllable first impedance means coupled to receive a signal varying with said control signal and having an impedance varying with said control signal, a second impedance means coupled to said first impedance means, a third impedance means coupled to said second impedance means, and a current dependent fourth impedance means coupled to said third impedance means and to said amplifier input and output, means coupled to said bridge for detecting unbalence therein; and means coupled to said detecting means for supplying a current to said current dependent impedance to vary the impedance thereof to restore said bridge to balance, whereby said current dependent impedance controls the feedback about said amplifier and hence the effective gain thereof in accordance with said control signal.
Claim 2
Dependent Claim
155 words
A circuit comprising a repeater station adapted to be controlled by a control signal, said station comprising an amplifier having an input and an output, a wheatstone bridge circuit comprising a current independent controllable first impedance means coupled to receive a signal varying with said control signal and having an impedance varying with said control signal, a second impedance means coupled to said first impedance means, a third impedance means coupled to said second impedance means, and a current dependent fourth impedance means coupled to said third impedance means and to said amplifier input and output, means coupled to said bridge for detecting unbalence therein; and means coupled to said detecting means for supplying a current to said current dependent impedance to vary the impedance thereof to restore said bridge to balance, whereby said current dependent impedance controls the feedback about said amplifier and hence the effective gain thereof in accordance with said control signal.
Claim 3
Dependent Claim
37 words
A circuit as claimed in claim 1 wherein one of said third and fourth impedance means comprises an adjustable impedance means, whereby the relationship between changes in said current dependent and independent impedance means can be adjusted.
Claim 4
Dependent Claim
21 words
A circuit as claimed in claim 1 wherein said repeater station is adapted to be controlled by a time modulated signal.
Claim 5
Dependent Claim
41 words
A circuit as claimed in claim 1 wherein said current independent impedance means comprises a capacitor, means for charging said capacitor, and means for discharging said capacitor, said charging and discharging means being adapted to receive a frequency modulated control signal.
Claim 6
Dependent Claim
42 words
A circuit as claimed in claim 1 wherein said current independent impedance means comprises a resistor and a transistor having emitter and collector electrodes series coupled to said resistor and a base electrode adapted to receive a pulse duration modulated control signal.
Claim 7
Dependent Claim
29 words
A circuit comprising a plurality of cascade coupled repeater stations as claimed in claim 1, the gain of each of said stations being controlled by the same control signal.
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) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |