Speech Decoder Attenuation for CELP Abnormal Sound Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing speech signal decoding technologies face issues with abnormal sound generation due to errors in encoded signals, particularly when encryption headers increase information volume or security is compromised, leading to degraded error detection and incomplete speech reproduction.
Innovation Solution
A speech signal decoding device incorporating an adaptive code-book decoder, fixed code-book decoder, ratio calculator, and attenuator, which calculates the amplitude or energy ratio between adaptive and fixed code-book components and attenuates the excitation signal when the ratio exceeds a threshold, preventing abnormal sound production without affecting normal signal reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an encryption header is added to the encoded signal, then error detection capability is improved, but the amount of information of the encoded signal increases
Solution Approach 1:
The patent extracts only the essential error detection information (parity bits) from a complete error detection code, transmitting only these extracted bits in the encryption header rather than the entire encoded error detection data, thus reducing header size while maintaining error detection capability
Solution Approach 2:
Instead of adding comprehensive error detection codes to the header, the patent inverts the approach by using a simplified parity check system that achieves error detection with minimal header information, turning a potential weakness (small header) into a strength (efficient error detection)
2Quantity of substance
If the header length is shortened to avoid increase in information volume, then information volume is reduced, but error detection performance is degraded
Solution Approach 1:
The patent changes the parameter of error detection from comprehensive error correction codes to simplified parity check bits, achieving adequate error detection performance with significantly reduced header length by altering the detection mechanism rather than maintaining full error correction capability
3Object-affected harmful factors
If speech signal output is stopped when decoded signal level exceeds threshold, then abnormal sound generation is prevented, but normal speech reproduction is also affected when original speech level is high
Solution Approach 1:
The patent implements feedback by continuously monitoring the relationship between adaptive and fixed codebook components, using this feedback to dynamically adjust signal attenuation only when error conditions are detected, rather than using simple threshold-based stopping that affects normal speech
Solution Approach 2:
The patent makes the signal processing dynamic by continuously adapting the attenuation decision based on real-time analysis of codebook component ratios, allowing the system to respond differently to error conditions versus normal high-level speech rather than using a static threshold approach
Data Source
AI summary
A speech signal decoding device includes an adaptive code-book decoder, a fixed code-book decoder, a ratio calculator, a determination unit, and an attenuator. The adaptive code-book decoder generates an adaptive code-book vector using an adaptive code-book code of an encoded signal encoded by a CELP method. The fixed code-book decoder generates a fixed code-book vector using a fixed code-book code of the encoded signal. The ratio calculator calculates an amplitude ratio or an energy ratio between the adaptive code-book vector and the fixed code-book vector. The determination unit determines whether the amplitude ratio or the energy ratio exceeds a predetermined threshold. When the amplitude ratio or the energy ratio is determined to exceed the predetermined threshold, the attenuator attenuates an excitation signal that has been defined by adding the adaptive code-book vector to the fixed code-book vector.