Patent US4823392A successfully refreshed from Google Patents.
US4823392A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compressor
Assignee: Nokia Deutschland GmbH
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Filing: 1987-02-12
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Granted: 1989-04-18
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Expires: 2007-02-12
Abstract
Abstract In a compressor for controlling the dynamic range of audio signals which comprises an operational amplifier and a gain-controlled amplifier connected in inverse parallel with the operational amplifier, the signal applied to a rectifier for producing the control signal for the gain-controlled amplifier is given an exponential waveform. This can be achieved by the use of two diodes connected in inverse parallel.
Inventors
- 👤 Michael Walker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:39
CPC Classifications
H; H03; H03G; H03G7/00; H03G7/002
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
110 words
A compressor for controlling the dynamic range of audio signals comprising: an operational amplifier; a gain-controlled amplifier connected in inverse parallel with said operational amplifier and having a control input; a rectifier connected to said control input and receiving an exponential waveform only from a given level of an audio signal applied to the input of said operational amplifier, and wherein an adjustable current is impressed on said rectifier; a PNP transistor having its base-emitter path connected to said rectifier, a base voltage divider being connected to the base of said transistor; a zener diode connecting the emitter of said transistor to ground; and a resistor connected to said rectifier.
Claim 2
Dependent Claim
110 words
A compressor for controlling the dynamic range of audio signals comprising: an operational amplifier; a gain-controlled amplifier connected in inverse parallel with said operational amplifier and having a control input; a rectifier connected to said control input and receiving an exponential waveform only from a given level of an audio signal applied to the input of said operational amplifier, and wherein an adjustable current is impressed on said rectifier; a PNP transistor having its base-emitter path connected to said rectifier, a base voltage divider being connected to the base of said transistor; a zener diode connecting the emitter of said transistor to ground; and a resistor connected to said rectifier.
Claim 3
Dependent Claim
130 words
A compressor for controlling the dynamic range of audio signals comprising: an operational amplifier; a gain-controled amplifier connected in inverse parallel with said operational amplifier and having a control input; a rectifier connected to said control input and receiving an exponential waveform only from a given level of an audio signal applied to the input of said operational amplifier, and wherein an adjustable current is impressed on said rectifier; first and second diodes connected in inverse parallel and connected to said rectifier and a resistor connected to said recitifier; and a field effect transistor having its source-drain path in series with said first and second diodes and said rectifier, and having a gate terminal connected to a supply voltage through a second resistor and to ground through a zener diode.
Claim 4
Dependent Claim
130 words
A compressor for controlling the dynamic range of audio signals comprising: an operational amplifier; a gain-controled amplifier connected in inverse parallel with said operational amplifier and having a control input; a rectifier connected to said control input and receiving an exponential waveform only from a given level of an audio signal applied to the input of said operational amplifier, and wherein an adjustable current is impressed on said rectifier; first and second diodes connected in inverse parallel and connected to said rectifier and a resistor connected to said recitifier; and a field effect transistor having its source-drain path in series with said first and second diodes and said rectifier, and having a gate terminal connected to a supply voltage through a second resistor and to ground through a zener diode.
Claim 5
Dependent Claim
107 words
A compressor for controlling the dynamic range of audio signals comprising: an operational amplifier; a gain-controlled amplifier connected in inverse parallel with said operational amplifier and having a control input; a rectifier connected to said control input and receiving an exponential waveform only from a given level of an audio signal applied to the input of said operational amplifier, and wherein an adjustable current is impressed on said recitifer; and first and second diodes connected in inverse parallel and connected to said rectifier and a resistor connected to said rectifier; said first and second diodes and said resistor being connected to the output of said operational amplifier.
Claim 6
Dependent Claim
107 words
A compressor for controlling the dynamic range of audio signals comprising: an operational amplifier; a gain-controlled amplifier connected in inverse parallel with said operational amplifier and having a control input; a rectifier connected to said control input and receiving an exponential waveform only from a given level of an audio signal applied to the input of said operational amplifier, and wherein an adjustable current is impressed on said recitifer; and first and second diodes connected in inverse parallel and connected to said rectifier and a resistor connected to said rectifier; said first and second diodes and said resistor being connected to the output of said operational amplifier.
Claim 7
Dependent Claim
110 words
A compressor for controlling the dynamic range of audio signals comprising: an operational amplifier; a gain-controlled amplifier connected in inverse parallel with said operational amplifier and having a control input; a rectifier connected to said control input and receiving an exponential waveform only from a given level of an audio signal applied to the input of said operational amplifier, and wherein an adjustable current is impressed on said rectifier; first and second diodes connected in inverse parallel and connected to said rectifier and a resistor connected to said rectifier; and a potentiometer for connecting said first and second diodes and said resistor to the input terminal for the audio signal.
Claim 8
Dependent Claim
110 words
A compressor for controlling the dynamic range of audio signals comprising: an operational amplifier; a gain-controlled amplifier connected in inverse parallel with said operational amplifier and having a control input; a rectifier connected to said control input and receiving an exponential waveform only from a given level of an audio signal applied to the input of said operational amplifier, and wherein an adjustable current is impressed on said rectifier; first and second diodes connected in inverse parallel and connected to said rectifier and a resistor connected to said rectifier; and a potentiometer for connecting said first and second diodes and said resistor to the input terminal for the audio signal.
Claim 9
Dependent Claim
141 words
A compressor for controlling the dynamic range of audio signals comprising: an operational amplifier; a gain-controlled amplifier connected in inverse parallel with said operational amplifier and having a control input; a rectifier connected to said control input and receiving an expoential waveform only from a given level of an audio signal applied to the input of said operational amplifier, and wherein an adjustable current is impressed on said rectifier; first and second diodes connected in inverse parallel and connected to said rectifier and a variable resistor having a sliding contact and being connected to said rectifier; a filter following said compressor; said first and second diode being connected to the output of said filter said resistor being connected to the output of said operational amplifier; and a current source for the adjustable current connected to said sliding contact of said resistor.
Claim 10
Dependent Claim
141 words
A compressor for controlling the dynamic range of audio signals comprising: an operational amplifier; a gain-controlled amplifier connected in inverse parallel with said operational amplifier and having a control input; a rectifier connected to said control input and receiving an expoential waveform only from a given level of an audio signal applied to the input of said operational amplifier, and wherein an adjustable current is impressed on said rectifier; first and second diodes connected in inverse parallel and connected to said rectifier and a variable resistor having a sliding contact and being connected to said rectifier; a filter following said compressor; said first and second diode being connected to the output of said filter said resistor being connected to the output of said operational amplifier; and a current source for the adjustable current connected to said sliding contact of said resistor.
References Cited (Backward Citations)
US4677678A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-17 | 1992-10-17 | 1993-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-17 | 1996-10-17 | 1997-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-17 | 2000-10-17 | 2001-04-18 | $7700.00 | Window Closed / Lapsed |