Integrated Audio Circuit Crosstalk Cancellation
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Solution Overview
Problem
Audio systems with multiple speakers, such as headsets, are susceptible to crosstalk noise due to undesired coupling between channels, which is particularly problematic in advanced audio applications like 3-D sound and noise cancellation.
Innovation Solution
An integrated audio signal processing circuit with feedforward circuits is used to couple inputs of channel circuits, with circuit parameters determined to eliminate crosstalk by ensuring detected output signals are zero when only one input signal is non-zero, utilizing signal detection and attenuation circuits to adjust parameters for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple speakers are used in an audio system, then audio quality and stereo sound capability are improved, but crosstalk noise increases due to undesired coupling between channels
Solution Approach 1:
The patent measures the crosstalk noise that naturally occurs in the system and converts this harmful effect into a beneficial correction signal. By measuring the crosstalk from each channel and injecting the inverse of this measured crosstalk through feedforward circuits, the system cancels out the unwanted coupling effects, transforming the harmful crosstalk into a useful cancellation mechanism that improves audio quality
Solution Approach 2:
The patent introduces feedforward circuits as intermediary elements between the audio input and speaker output. These circuits receive the original audio signal, measure the crosstalk that occurs during normal operation, and inject a corrected signal that cancels the crosstalk before it reaches the speaker. This intermediary processing stage allows the system to maintain multiple speakers while eliminating their harmful coupling effects
2Object-affected harmful factors
If feedforward circuits are added to reduce crosstalk, then crosstalk noise is reduced, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into integrated circuits that perform both audio signal processing and crosstalk measurement/cancellation. The feedforward circuits are merged with the existing audio amplifier and speaker driver circuits, allowing the system to reduce crosstalk without adding completely separate, complex subsystems. This integration approach minimizes the increase in device complexity while achieving effective crosstalk reduction
Data Source
AI summary
An audio system has a first channel for receiving a first input signal and driving a first speaker and a second channel for receiving a second input signal and driving a second speaker. A first feedforward circuit couples an input of the second channel circuit to an input of the first channel circuit. A second feedforward circuit couples an input of the first channel circuit to an input of the second channel circuit. Circuit parameters of the first and the second feedforward circuits are determined such that a first detected output signal is zero when the first input signal is non-zero and the second input signal is zero, and a second detected output signal is zero when the second input signal is non-zero and the first input signal is zero. The audio system is configured to operate using the determined circuit parameters for the first and the second feedforward circuits.