Dynamic Anti-Aliasing Suppression for Sub-Band Echo Cancellation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wideband telephony echo canceller systems face significant processing challenges due to non-linear aliasing components in sub-bands, which increase processing load and resource consumption when signals are not merged immediately after decoding, leading to inefficient echo cancellation and digital signal processing.
Innovation Solution
A dynamic anti-aliasing suppression method is applied to sub-band digital signals, with varying aggressiveness levels based on the activity of near and far-end audio inputs, using a simulated digital signal to subtract aliasing components, allowing for efficient echo cancellation and DSP at lower sampling frequencies with reduced resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If sub-bands are decoded and processed separately at low sampling frequency to reduce processing load, then processing resources are reduced, but non-linear aliasing components are introduced into the sub-band signals
Solution Approach 1:
The patent extracts and removes the non-linear aliasing components from the sub-band signals through a dedicated aliasing suppression module. This module identifies and separates the aliasing components from the useful signal content, allowing the system to process sub-bands at reduced sampling rates while maintaining signal quality by eliminating the harmful aliasing artifacts.
Solution Approach 2:
The patent introduces an intermediary aliasing suppression module between the sub-band decoding and echo cancellation stages. This intermediary component processes the sub-band signals to suppress aliasing before they propagate to subsequent processing stages, enabling low-rate processing without compromising overall system performance.
2Ease of operation
If sub-bands are not merged immediately after decoding to enable echo cancellation and DSP on low frequency sub-bands, then processing can be performed at lower sampling frequency, but each sub-band signal carries significant non-linear aliasing component
Solution Approach 1:
The patent converts the aliasing components, which are normally harmful artifacts, into manageable signals through the aliasing suppression module. By designing a module that specifically targets and suppresses these aliasing components, the system transforms what would be signal degradation into an controlled processing step, enabling reliable low-rate operation.
Solution Approach 2:
The patent applies aliasing suppression as a preliminary action before echo cancellation and other DSP operations. By suppressing the aliasing components in advance, the subsequent processing stages operate on cleaner signals, improving the reliability of echo cancellation and other digital signal processing operations performed on the low-frequency sub-bands.
3Quantity of substance
If processing is performed on sub-bands separately rather than merging and processing at high sampling rate, then resource consumption is reduced, but echo cancellation effectiveness may be compromised due to aliasing
Solution Approach 1:
The patent introduces an intermediary aliasing suppression module that bridges the gap between low-rate sub-band processing and high-quality echo cancellation. This module ensures that the aliasing components do not interfere with the echo cancellation process, allowing the system to achieve effective echo cancellation using reduced computing resources.
Solution Approach 2:
The patent replaces the traditional approach of merging sub-bands at high sampling rate with a substituted approach that processes sub-bands separately at lower rates with aliasing suppression. This substitution maintains echo cancellation effectiveness while significantly reducing the computational mechanics required for processing.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
It is respectfully submitted that the Abstract exceeds 150 words. A suggested re-wording follows: A method of for aliasing suppression in a sub-band speaker-phone system, comprising receiving an analog audio signal from a near end analog audio input interface, subtracting a simulated digital signal from said sub-band digital audio signal, wherein said simulated digital signal is created by an echo canceling unit; and applying dynamic anti aliasing suppression with varying aggressiveness on each of said N greater than or equal to 2 near-end sub-band digital audio signals.