Echo Canceller High-Frequency Leakage Suppression
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Solution Overview
Problem
Echoes in communication systems, caused by mismatched transmission line impedances or improper hybrid architectures, degrade the signal-to-noise ratio (SNR) due to ineffective echo cancellation methods that rely on lower sampling rates.
Innovation Solution
An echo canceller system and method that updates filter coefficients using a high-frequency leakage process, generating echo cancelling signals at higher sampling rates to effectively cancel echoes and improve SNR, incorporating oversampling and filtering mechanisms to suppress high-frequency components and prevent signal drifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If echo cancellation is performed using conventional methods with lower sampling rates, then the system complexity is reduced, but the echo cancellation effectiveness deteriorates and signal-to-noise ratio decreases
Solution Approach 1:
The patent changes the sampling rate parameter from conventional lower rates to higher rates (e.g., 400 MHz or above), which directly improves echo cancellation effectiveness by capturing more high-frequency echo components. This parameter change resolves the contradiction by accepting higher system complexity as a necessary trade-off for achieving reliable echo cancellation in modern high-speed communication systems.
Solution Approach 2:
The patent implements dynamic filter coefficient adaptation through the FxLMS algorithm, which continuously adjusts coefficients based on real-time signal characteristics. This dynamic approach enables effective echo cancellation across varying communication conditions while managing system complexity through adaptive rather than static processing.
2Reliability
If filter coefficients are updated without high-frequency leakage suppression, then the filtering speed is maintained, but signal drifting occurs and system stability deteriorates
Solution Approach 1:
The patent extracts and separately processes the high-frequency leakage components from the filter coefficient updates. By identifying and removing these problematic high-frequency components before applying coefficient updates, the system prevents signal drifting and maintains stability without significantly compromising the overall filtering speed and echo cancellation performance.
3Measurement precision
If high-frequency components are not suppressed, then the echo cancellation operates at full speed, but signal drifting occurs and echo cancellation accuracy deteriorates
Solution Approach 1:
The patent introduces an intermediary high-frequency leakage suppression mechanism that sits between the conventional filtering process and the final echo cancellation output. This intermediary component selectively removes problematic high-frequency leakage components while preserving useful high-frequency echo cancellation signals, thereby improving accuracy without requiring a complete redesign of the signal processing architecture.
Data Source
AI summary
An echo canceller system includes a data transmitter circuit and an echo canceller circuit. The data transmitter circuit is configured to receive a transmitted signal. The echo canceller circuit includes a first filter. The first filter is configured to generate a first filtered signal according to the transmitted signal and a filter coefficient vector. The filter coefficient vector is updated according to a high-frequency leakage process. The echo canceller circuit is further configured to generate an echo cancelling signal according to the first filtered signal. The data transmitter circuit is further configured to generate an output signal according to a received signal and the echo cancelling signal.