Gain Parameter Estimation Saturation Prevention

Solution Overview

Problem

In audio signal transmission using bandwidth extension, high band signal energy calculations can lead to saturation, resulting in inaccurate gain parameter estimation and degradation of audio quality due to limited bit representation in fixed-point systems.

Innovation Solution

Scaling the high band signal before energy calculation to prevent saturation, using scaling factors such as 2, 4, or 8, to ensure the energy value fits within available bit representation, thereby accurately determining gain shape and frame parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If energy value is calculated directly without scaling in fixed-point systems, then computation speed is maintained, but saturation occurs when energy value exceeds available bit representation, causing loss of precision in gain parameter estimation

Engineering Contradiction:

Improvegain parameter estimation accuracyVSAvoidcomputation complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary scaling to the high band signal before energy calculation to prevent saturation. By scaling the signal by a factor (e.g., 2, 4, or 8) before computing the energy value, the system ensures that the energy calculation remains within the representable range of fixed-point arithmetic, thereby avoiding saturation and maintaining measurement precision without requiring complex post-processing corrections

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If signal scaling is applied before energy calculation, then saturation is prevented and gain parameter accuracy is improved, but additional computational steps and memory operations are required

Engineering Contradiction:

Improveenergy value accuracyVSAvoidencoding speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent changes the scale parameter of the high band signal by applying a scaling factor before energy calculation. This parameter transformation ensures that the signal energy remains within the dynamic range of fixed-point representation, preventing saturation and improving energy value accuracy. The scaling factor is carefully selected to balance precision improvement with minimal impact on encoding speed

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If fixed-point representation with limited bits is used, then memory usage and transmission bandwidth are reduced, but saturation occurs at high energy levels causing audio quality degradation

Engineering Contradiction:

Improvedata representation efficiencyVSAvoidaudio quality consistency

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies preliminary scaling to the high band signal before energy calculation to prevent saturation. By scaling the signal by a factor (e.g., 2, 4, or 8) before computing the energy value, the system ensures that the energy calculation remains within the representable range of fixed-point arithmetic, thereby avoiding saturation and maintaining measurement precision without requiring complex post-processing corrections

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The scaling factor acts as an intermediary element that bridges the gap between the high energy signal and the limited fixed-point representation. By introducing this intermediate scaling operation, the system can accurately represent high energy values without exceeding the bit representation limits, thus maintaining audio quality consistency while using efficient fixed-point data representation

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP3796312B1Gain parameter estimation based on saturation and scaling of an audio signal

Publication Date: 2022.06.15 QUALCOMM INC

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AI summary

A device including gain shape circuitry configured to determine a number of sub-frames of multiple sub-frames that are saturated, the multiple sub-frames included in a frame of a high band audio signal. The device also includes gain frame circuitry configured to determine, based on the number of sub-frames that are saturated, a gain frame parameter corresponding to the frame.