In-Vehicle Seat Audio Relay With Adaptive Feedback Cancellation
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Solution Overview
Problem
In vehicle communication systems, users at different seats often hear sounds from each other's sound sources, and there is a problem with howling or delayed voice feedback when a user's voice is output from one seat and collected again by a microphone at another seat, causing discomfort and interference.
Innovation Solution
An in-vehicle communication support system with a noise control unit that includes an adaptive filter and a selector to output either the second seat sound source or the user's voice signal, using error signals and transfer functions to minimize interference and cancel unwanted sounds, with two operation modes to manage voice and sound source outputs effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the uttered voice of a user seated on a first seat is collected by a microphone for the first seat and output from a speaker for a second seat, then communication between users at different seats is supported, but the uttered voice may be collected again by the microphone for the first seat causing howling or delayed voice feedback
Solution Approach 1:
The patent introduces a noise control unit as an intermediary between the microphone and speaker systems. This unit includes an adaptive filter that generates cancel sounds to actively suppress the feedback path, allowing voice communication between seats while preventing the microphone from picking up its own output. The cancel sound generation breaks the feedback loop without blocking the useful communication path.
Solution Approach 2:
The system uses feedback control through the adaptive filter that continuously monitors the microphone output and adjusts the cancel sound generation accordingly. The filter adapts its transfer function based on the detected feedback path characteristics, dynamically suppressing howling while maintaining clear voice transmission between users at different seats.
2Adaptability or versatility
If users at different seats listen to sounds of different sound sources, then each user can have personalized audio experience, but one or more users may still hear sounds of sound sources listened by other users
Solution Approach 1:
The noise control unit acts as an intermediary that processes sound signals between the second seat speaker and first seat microphone path. It generates cancel sounds specifically targeted at suppressing leakage of second seat audio content to the first seat, while preserving the personalized audio experience for each user.
Solution Approach 2:
The system applies localized noise cancellation by generating cancel sounds that are specifically directed at the feedback path from the second seat speaker to the first seat microphone. This allows personalized audio content to be delivered to each seat while locally suppressing cross-seat interference without affecting the overall system performance.
3Reliability
If a noise control unit with adaptive filter is used to cancel noise, then noise cancellation performance is improved, but system complexity increases due to additional components and processing
Solution Approach 1:
The noise control unit is designed to perform multiple functions: it cancels feedback howling, suppresses cross-seat sound leakage, and maintains clear voice communication. By consolidating these functions into a single integrated unit with an adaptive filter, the system achieves high noise cancellation performance without proportionally increasing complexity.
Solution Approach 2:
The adaptive filter automatically adapts its transfer function based on the detected acoustic environment and feedback path characteristics. This self-adjusting capability eliminates the need for manual configuration or complex control mechanisms, allowing the system to achieve optimal noise cancellation performance while keeping the control structure relatively simple.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents users from hearing each other's sound sources and suppresses voice feedback loops, ensuring clear communication between users at different seats by effectively canceling noise and voice interference.
Implementation Method 1
a first adaptive filter configured to receive the reference sound as an input and perform an adaptive operation of updating a transfer function so as to reduce a magnitude of the error signal to generate the cancel sound
Implementation Method 2
a noise control unit configured to output a cancel sound and an uttered voice signal; a first seat speaker configured to output a cancel sound output by the noise control unit
Implementation Method 3
a microphone configured to collect sound of the first seat
Data Source
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AI summary
To provide an "in-vehicle communication support system" that cancels an unnecessary sound and relays an uttered voice. A transfer function of a first variable filter (71) is updated so as to output, from an output (M) of a first seat microphone (5), a cancel sound (C) that minimizes a level of a signal obtained by subtracting an output of an auxiliary filter (75) that generates a correction signal for correcting a difference between positions of the first seat microphone (5) and the first seat. In the ICC mode in which the uttered voice of the user in the first seat is output from a second seat speaker (4), a selector (6) sets an uttered voice Dp output from the second seat speaker (4) as an input to the first variable filter (71), and in the non-ICC mode, the selector (6) sets an output sound (A2) of a second seat audio source (2) output from the second seat speaker (4) as an input to the first variable filter (71). The uttered voice Dp is generated by removing a component of the cancel sound (C) from the output (M) of the first seat microphone (5).