Patent US3986049A successfully refreshed from Google Patents.
US3986049A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Audio compressor/limiter amplifier
Assignee: Motorola Solutions Inc
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Filing: 1975-06-30
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Granted: 1976-10-12
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Expires: 1995-06-30
Abstract
Abstract An audio compressor amplifier including an operational amplifier with compressor means connected from the output to the input for compressing signals at the output to a predetermined constant level in a predetermined attack time and including a plurality of diodes connected to reduce the series resistance in the compressor means for decreasing the attack time when the output signal exceeds the predetermined constant level by a predetermined amount, and a gain control feedback resistor connected from the output to the input of the operational amplifier and including a second resistor and a plurality of diodes connected in parallel therewith to reduce the gain of the operational amplifier and provide peak limiting action when a signal at the output exceeds a predetermined value in excess of the predetermined constant level.
Inventors
- 👤 Whitney Robertson Campbell
- 👤 Raymond Maurice Fardoux
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:36
CPC Classifications
H; H03; H03G; H03G7/00; H03G7/002; H03G7/004
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
152 words
An audio compressor amplifier comprising: a. an audio amplifier circuit having an output and an input; b. compressor means connected from the output to the input of said amplifier circuit for controlling the input of said amplifier circuit to compress signals at the output to a predetermined constant level in a predetermined attack time; c. semiconductor means connected in said compressor means for decreasing the attack time when the output signal exceeds the predetermined constant level by a predetermined amount; d. gain control feedback means connected from the output to the input of said amplifier circuit for controlling the gain thereof; and e. semiconductor controlled circuitry connected to the output of said amplifier circuit and said gain control feedback means for controlling said gain control feedback means to reduce the gain of said amplifier circuit when a signal at the output exceeds a predetermined value in excess of the predetermined constant level.
Claim 2
Dependent Claim
152 words
An audio compressor amplifier comprising: a. an audio amplifier circuit having an output and an input; b. compressor means connected from the output to the input of said amplifier circuit for controlling the input of said amplifier circuit to compress signals at the output to a predetermined constant level in a predetermined attack time; c. semiconductor means connected in said compressor means for decreasing the attack time when the output signal exceeds the predetermined constant level by a predetermined amount; d. gain control feedback means connected from the output to the input of said amplifier circuit for controlling the gain thereof; and e. semiconductor controlled circuitry connected to the output of said amplifier circuit and said gain control feedback means for controlling said gain control feedback means to reduce the gain of said amplifier circuit when a signal at the output exceeds a predetermined value in excess of the predetermined constant level.
Claim 3
Dependent Claim
18 words
An audio compressor amplifier as claimed in claim 1 wherein the audio amplifier circuit includes an operational amplifier.
Claim 4
Dependent Claim
19 words
An audio compressor amplifier as claimed in claim 2 wherein the gain control feedback means includes a first resistor.
Claim 5
Dependent Claim
68 words
An audio compressor amplifier as claimed in claim 3 wherein the semiconductor controlled circuitry includes a second resistor and a pair of diodes connected to be normally reverse biased and to be forward biased by a signal a predetermined value in excess of the predetermined constant level at the amplifier output, said diodes connecting said second resistor in parallel with said first resistor in the forward biased condition.
Claim 6
Dependent Claim
67 words
An audio compressor amplifier as claimed in claim 1 wherein the compressor means includes rectifying and filtering circuitry for converting an AC signal at the output of the amplifier circuit to a DC control signal and a transistor connected to the input of the amplifier circuit and controlled by the DC control signal for varying the amount of signal applied to the input of the amplifier circuit.
Claim 7
Dependent Claim
64 words
An audio compressor amplifier as claimed in claim 5 wherein the rectifying and filtering circuitry has a resistance in series therewith for providing a predetermined attack time in the compressor means and the semiconductor means includes a plurality of diodes connected in parallel with said resistance for bypassing said resistance with signals larger than a predetermined value in excess of the predetermined constant level.
Claim 8
Dependent Claim
65 words
An audio compressor amplifier as claimed in claim 6 wherein the plurality of diodes includes at least two diodes connected in series and the series circuit connected in parallel with the resistance in a first direction and at least two more diodes connected in series and the series circuit connected in parallel with the resistance in a second direction for bypassing signals of either polarity.
Claim 9
Dependent Claim
212 words
An audio compressor amplifier comprising: a. an operational amplifier having an output and an input; b. rectifying and filtering circuitry for converting an AC signal at the output of said operational amplifier to a DC control signal and a transistor connected to the input of said operational amplifier and controlled by the DC control signal for varying the amount of signal applied to the input of said operational amplifier to compress signals at the output to a predetermined constant level; c. first resistance means in series with said rectifying and filtering circuitry for providing a predetermined attack time and a plurality of diodes connected in parallel with said first resistance means for bypassing said first resistance means with signals larger than a predetermined value in excess of the predetermined constant level; d. second resistance means connected from the output to the input of said operational amplifier for controlling the gain thereof; and e. semiconductor controlled circuitry including third resistance means connected to the output of said operational amplifier and to said second resistance means for connecting the third resistance means in parallel with said second resistance means to reduce the gain of said operational amplifier when a signal at the output exceeds a predetermined value in excess of the predetermined constant level.
Claim 10
Dependent Claim
212 words
An audio compressor amplifier comprising: a. an operational amplifier having an output and an input; b. rectifying and filtering circuitry for converting an AC signal at the output of said operational amplifier to a DC control signal and a transistor connected to the input of said operational amplifier and controlled by the DC control signal for varying the amount of signal applied to the input of said operational amplifier to compress signals at the output to a predetermined constant level; c. first resistance means in series with said rectifying and filtering circuitry for providing a predetermined attack time and a plurality of diodes connected in parallel with said first resistance means for bypassing said first resistance means with signals larger than a predetermined value in excess of the predetermined constant level; d. second resistance means connected from the output to the input of said operational amplifier for controlling the gain thereof; and e. semiconductor controlled circuitry including third resistance means connected to the output of said operational amplifier and to said second resistance means for connecting the third resistance means in parallel with said second resistance means to reduce the gain of said operational amplifier when a signal at the output exceeds a predetermined value in excess of the predetermined constant level.
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) | 1979-10-12 | 1980-04-12 | 1980-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-12 | 1984-04-12 | 1984-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-12 | 1988-04-12 | 1988-10-12 | $7700.00 | Window Closed / Lapsed |