Automatic Gain Control for Multi-Talker Audio Systems

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Solution Overview

Problem

In multi-talker environments, existing audio systems struggle to rapidly adjust gain levels when a talker transitions from soft to loud or vice versa, leading to inconsistent volume, as traditional AGC algorithms take several seconds to respond effectively.

Innovation Solution

The audio system employs a fast-attack/decay AGC algorithm for unidentified talkers to quickly determine a gain value and applies pre-determined gains for recognized talkers, combining these techniques to rapidly adjust and maintain consistent volume across multiple talkers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a traditional AGC algorithm is used to adjust gain levels, then the system maintains stable volume control, but the response time is slow (several seconds) when a talker transitions from soft to loud

Engineering Contradiction:
Improveresponse time of AGC algorithmVSAvoidvolume consistency
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent implements dynamic AGC parameters by detecting talker presence and adjusting attack/decay rates based on whether a talker is identified or unidentified. For unidentified talkers, the system uses fast attack/decay rates to quickly respond to volume changes, while for identified talkers, it uses traditional slower rates to maintain stability. This dynamic adaptation resolves the contradiction between fast response and volume consistency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameters of the AGC algorithm based on talker identification status. When an unidentified talker is detected, the attack and decay rates are increased to accelerate response. When a recognized talker is detected, the traditional slower rates are used. This parameter adaptation allows the system to achieve both fast response when needed and stable control when appropriate.

Inventive Principle:
Principle #35Parameter changes

2Speed

If the AGC algorithm increases attack and decay rates for fast response, then the response time improves, but the system may cause instability in volume control

Engineering Contradiction:
Improvegain adjustment speedVSAvoidvolume stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent applies different AGC characteristics to different talker categories. Unidentified talkers receive fast attack/decay treatment for rapid response, while identified talkers receive traditional slower treatment for stability. This localized differentiation allows fast response where critical (unidentified talkers) while maintaining stability where appropriate (identified talkers).

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2592546B1Automatic Gain Control in a multi-talker audio system
Publication Date: 2015.01.07 GOOGLE LLC
  • EP2592546B1 patent drawingFigure 1
  • EP2592546B1 patent drawingFigure 2
  • EP2592546B1 patent drawingFigure 3

AI summary

In general, the techniques are described for adjusting audio gain levels for multi-talker audio. In one example, an audio system monitors an audio stream for the presence of a new talker. Upon identifying a new talker, the system determines whether the new talker is a first-time talker. For a first-time talker, the system executes a fast-attack/decay automatic gain control (AGC) algorithm to quickly determine a gain value for the first-time talker. The system additionally executes standard AGC techniques to refine the gain for the first-time talker while the first-time talker continues speaking. When a steady state within a decibel threshold is attained using standard AGC for the first-time talker, the system stores the steady state gain for the first-time talker to storage. Upon identifying a previously-identified talker, the system retrieves from storage the steady state gain for the talker and applies the steady state gain to the audio stream.