Patent US4634997A successfully refreshed from Google Patents.
US4634997A
Expired / Lapsed
US
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Automatic gain control amplifier circuit
Assignee: Nokia Bell Labs
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Filing: 1984-11-13
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Granted: 1987-01-06
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Expires: 2004-11-13
Abstract
Abstract An automatic gain control (AGC) amplifier circuit uses a control loop comprising a digital counter (70) which controls a multiplying digital-to-analog converter (10) arranged as an attenuator of the input v to the AGC. The counter (70) is arranged to count up or down depending upon the output signal of the AGC circuit. In addition, a latency can be introduced into the control loop so that in case of most signal envelope variations, the counter is frozen to prevent output fluctuations.
Inventors
- 👤 Michael F. Tompsett
- 👤 Edward J. Zimany, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:22
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
149 words
An automatic gain control circuit comprising (a) a digital electronic counter; (b) a multiplying digital-to-analog converter connected for directly attenuating an input signal in accordance with the instantaneous reading of the counter, to produce an attenuated signal; (c) an amplifier arrangement connected for receiving the attenuated signal and for developing an amplified output signal in accordance with the attenuated signal; (d) a comparator means connected for receiving the amplified output signal and for generating a binary comparator output signal to increase or decrease the reading of the counter depending upon whether the amplified output signal is above or below a prescribed level; and (e) a latency network, connected for intergrating the binary comparator output signal and for enabling the reading of the counter to increase or decrease when and only when the binary signal integrates to a value which is above or below, respectively, first or second reference values.
Claim 2
Dependent Claim
149 words
An automatic gain control circuit comprising (a) a digital electronic counter; (b) a multiplying digital-to-analog converter connected for directly attenuating an input signal in accordance with the instantaneous reading of the counter, to produce an attenuated signal; (c) an amplifier arrangement connected for receiving the attenuated signal and for developing an amplified output signal in accordance with the attenuated signal; (d) a comparator means connected for receiving the amplified output signal and for generating a binary comparator output signal to increase or decrease the reading of the counter depending upon whether the amplified output signal is above or below a prescribed level; and (e) a latency network, connected for intergrating the binary comparator output signal and for enabling the reading of the counter to increase or decrease when and only when the binary signal integrates to a value which is above or below, respectively, first or second reference values.
Claim 3
Dependent Claim
17 words
The circuit of claim 1 in which the multiplying digital-to-analog converter is essentially a switched capacitor attenuator.
Claim 4
Dependent Claim
32 words
The circuit of claim 2 which further includes means for referencing the multiplying digital-to-analog converter to a low pass component of the amplified output circuit in order to reduce dc offset amplification.
Claim 5
Dependent Claim
32 words
The circuit of claim 1 which further includes means for referencing the multiplying digital-to-analog converter to a low pass component of the amplified output circuit in order to reduce dc offset amplification.
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) | 1990-01-05 | 1990-07-07 | 1991-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-05 | 1994-07-07 | 1995-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-05 | 1998-07-07 | 1999-01-06 | $7700.00 | Window Closed / Lapsed |