Acoustic Bandwidth Extension Without Block Artifacts or Delay

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Solution Overview

Problem

Existing bandwidth extension systems for acoustic signals often introduce noticeable artifacts and delays due to block processing, which restrict the quality and comprehensibility of reconstructed signals.

Innovation Solution

A bandwidth extension system that generates upper and lower bandwidth extension signals by shifting and filtering the received acoustic signal using high-pass and spectral shifters, along with non-linear characteristics to create harmonics, and combines these signals with the original to produce an extended bandwidth acoustic signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If block processing is used to reconstruct missing frequency components, then bandwidth extension is achieved, but noticeable artifacts and delays are introduced

Engineering Contradiction:

Improvemissing frequency componentsVSAvoidblock offset artifacts

Core Design Contradiction:

Loss of informationVSObject-generated harmful factors

Solution Approach 1:

The patent implements continuous processing of the acoustic signal through filter banks without dividing it into discrete blocks. This continuous action eliminates the block offset artifacts that occur when signals are processed in separate segments, while still achieving bandwidth extension by synthesizing missing frequency components through the continuous filter bank operations.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent segments the frequency spectrum into multiple bands using filter banks, allowing independent processing of different frequency ranges. This segmentation enables targeted reconstruction of missing high-frequency components while maintaining the continuous time-domain signal, thus avoiding block artifacts while achieving spectral extension.

Inventive Principle:

Principle #1Segmentation

2Loss of information

If block processing is used to reconstruct missing frequency components, then bandwidth extension is achieved, but signal delay is introduced

Engineering Contradiction:

Improvemissing frequency componentsVSAvoidsignal delay

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

By processing the signal continuously through overlapping window functions and filter banks rather than in discrete blocks, the system eliminates the temporal delays inherent in block-based processing. The continuous operation allows immediate reconstruction of frequency components without waiting for complete blocks to be processed.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent applies preliminary windowing and filtering operations to the signal before frequency analysis, preparing it for continuous processing. This preliminary action enables the system to maintain signal continuity and reduce processing delays by having the signal pre-conditioned for immediate spectral reconstruction without block-based waiting periods.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If transmission path restricts bandwidth of acoustic signals, then signal transmission is simplified, but quality and comprehensibility suffer

Engineering Contradiction:

Improvetransmission path complexityVSAvoidsignal quality

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent changes the frequency domain parameters of the transmitted signal by synthesizing missing high-frequency components through filter bank operations. This parameter transformation allows the system to work with restricted bandwidth transmission paths while reconstructing full-bandwidth quality signals at the receiver, effectively decoupling transmission simplicity from output quality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The filter bank system acts as an intermediary between the restricted bandwidth transmission path and the desired full-bandwidth output. It mediates by taking the limited frequency range from the transmission path and using spectral reconstruction techniques to generate the missing frequency components, thereby improving signal quality without increasing transmission path complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The system effectively extends the bandwidth of acoustic signals without introducing significant artifacts or delays, improving signal quality and comprehensibility by reconstructing missing frequency components and adapting to changes in the signal.

Implementation Method 1

By shifting a portion of the signal by a frequency value, the system generates an upper bandwidth extension signal

Methodology Applied

Scientific EffectFrequency shifting:

Implementation Method 2

The system processes the acoustic signal to generate an upper bandwidth extension signal

Methodology Applied

Scientific EffectFiltering: Filter (electronic)

Data Source

PatentUS8160889B2System for providing an acoustic signal with extended bandwidth

Publication Date: 2012.04.17 CERENCE OPERATING CO

AI summary

A bandwidth extension system extends the bandwidth of an acoustic signal. By shifting a portion of the signal by a frequency value, the system generates an upper bandwidth extension signal. An extended bandwidth acoustic signal may be generated from the acoustic signal, the upper bandwidth extension signal, and/or a lower bandwidth extension signal.