Wireless Audio Equalizer Tuning for PESQ-Based Speech Quality
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Solution Overview
Problem
Existing wireless communication devices face challenges in maintaining high sound quality during audio signal transmission due to subjective setting of sound quality, surrounding noise, and variations in microphone characteristics, leading to potential deterioration of sound quality.
Innovation Solution
A wireless communication device equipped with an equalizer that adjusts frequency characteristics based on predetermined gain settings, encodes and decodes audio signals using the AMBE+2 scheme, and employs a sound quality evaluator to optimize gain settings for improved perceptual speech quality (PESQ) through continuous evaluation and adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If audio signals are encoded with high compression rate for wireless transmission, then transmission efficiency is improved, but sound quality deteriorates
Solution Approach 1:
The equalizer performs preliminary adjustment of frequency characteristics on the audio signal before encoding. By pre-adjusting the frequency spectrum to optimize for the chosen compression scheme, the system prepares the signal in advance to minimize quality loss during compression, thus maintaining sound quality while achieving efficient transmission.
Solution Approach 2:
The system dynamically changes frequency response parameters through equalizer adjustment based on the selected encoding scheme and transmission conditions. By modifying frequency gain parameters adaptively, the system optimizes the audio signal characteristics to withstand compression effects, thereby preserving sound quality during high-rate compression transmission.
2Device complexity
If subjective sound quality settings are used in the transmitter, then device complexity is reduced, but adaptability to surrounding noise and microphone characteristics deteriorates
Solution Approach 1:
The receiver performs objective sound quality evaluation using PESQ (Perceptual Evaluation of Speech Quality) and feeds back the evaluation results to the transmitter. This feedback loop enables the transmitter to adaptively adjust equalizer settings based on actual transmission conditions and receiver performance, achieving high adaptability without significantly increasing transmitter complexity since the complex evaluation is performed at the receiver side.
Solution Approach 2:
The receiver autonomously performs sound quality evaluation and generates feedback information without requiring complex control mechanisms at the transmitter. The system uses the receiver's own resources to assess quality and communicate adjustment needs, reducing the overall system complexity while maintaining high adaptability.
3Device complexity
If fixed frequency characteristics are used for audio signal transmission, then device complexity is reduced, but sound quality under varying conditions deteriorates
Solution Approach 1:
The equalizer dynamically adjusts frequency characteristics based on feedback from the receiver and current transmission conditions. Instead of using fixed frequency response, the system adapts the equalizer parameters in real-time to match varying noise environments, microphone characteristics, and encoding schemes, thereby maintaining consistent sound quality across different operating conditions without requiring overly complex processing.
Data Source
AI summary
A wireless communication device includes an equalizer configured to adjust a frequency characteristic of a user audio signal on the basis of a predetermined gain setting and to generate an adjusted signal, or an adjusted audio signal; an encoder configured to encode the adjusted signal with a preset scheme to generate an encoded signal; a decoder configured to decode the encoded signal to generate a decoded signal; a sound quality evaluator configured to carry out a PESQ evaluation of the decoded signal and to generate an evaluation result with the user audio signal serving as a reference signal for evaluation; and a selector configured to change the gain setting and to select a gain setting yielding a high evaluation result.