Automatic loudness controller
First Claim
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1. Apparatus for automatically controlling the level of audio frequency program signals to maintain uniform average loudness of sounds corresponding to said signals while simultaneously holding the signal level below a preset limit, said apparatus comprising, in combination:
- variable gain means connected to receive and adapted to amplify input audio frequency program signals and produce amplified output signals;
loudness analyzing means operative responsively to said amplified output signals for producing a first control signal for controlling the gain of said variable gain means in accordance with loudness level of the program signals;
signal level analyzing means operative responsively to said amplified output signals for producing a second control signal for controlling the gain of said variable gain means in accordance with the signal level of the program signals and for limiting the amount of gain which can be contributed by said loudness analyzing means; and
logic means connected to receive and operative responsively to said first and second control signals for determining which should be in control of said variable gain means and for connecting the appropriate control signal to said variable gain means.
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Abstract
The herein-described broadcast apparatus for controlling the loudness level of program signals includes a variable gain device for increasing or decreasing the level of incoming program material as a function of program loudness while simultaneously holding the output level below a preset level to assure proper modulation levels and/or to prevent excessive reaction by peak limiters which usually follow the loudness controller in the broadcast chain.
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8 Claims
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1. Apparatus for automatically controlling the level of audio frequency program signals to maintain uniform average loudness of sounds corresponding to said signals while simultaneously holding the signal level below a preset limit, said apparatus comprising, in combination:
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variable gain means connected to receive and adapted to amplify input audio frequency program signals and produce amplified output signals; loudness analyzing means operative responsively to said amplified output signals for producing a first control signal for controlling the gain of said variable gain means in accordance with loudness level of the program signals; signal level analyzing means operative responsively to said amplified output signals for producing a second control signal for controlling the gain of said variable gain means in accordance with the signal level of the program signals and for limiting the amount of gain which can be contributed by said loudness analyzing means; and logic means connected to receive and operative responsively to said first and second control signals for determining which should be in control of said variable gain means and for connecting the appropriate control signal to said variable gain means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification