Echo Gain Change Detection Using Threshold Logic
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Solution Overview
Problem
Conventional echo cancellers in telephone networks face significant performance degradation due to slow convergence in response to quick changes in echo path characteristics, such as when a parallel handset is picked up or replaced, leading to suboptimal echo cancellation and interactivity.
Innovation Solution
A system employing a first circuit to synthesize a vector by filtering another vector and a second circuit to generate a gain, compare it to thresholds, and update the filter vector accordingly, using an Infinite Impulse Response filter and simple threshold logic for fast echo gain change detection, allowing for quick echo gain correction with low processing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional echo cancellers use steady state tracking to remove most echoes, then echo cancellation performance is improved, but the system responds slowly to quick changes in echo path characteristics
Solution Approach 1:
The system dynamically adapts its behavior based on detected echo gain changes. When a quick change is detected through threshold comparison, the system transitions from steady-state tracking to a fast re-convergence mode, making the echo canceller's response characteristics variable rather than fixed, thus resolving the contradiction between steady-state performance and transient response speed
Solution Approach 2:
The system continuously monitors the received signal for echo gain changes and uses this feedback to trigger re-convergence procedures. By comparing the current signal characteristics against thresholds and detecting deviations, the system creates a feedback loop that activates fast adaptation mechanisms when needed, improving response speed while maintaining steady-state performance during normal operation
2Adaptability or versatility
If echo cancellers run full EPC procedure and re-converge after echo path changes, then adaptation to new echo characteristics is achieved, but system performance degrades significantly during the re-convergence period
Solution Approach 1:
The system performs preliminary detection of echo gain changes by continuously monitoring signal characteristics and comparing them against thresholds. This preliminary action allows the system to prepare for and initiate fast re-convergence procedures earlier, reducing the performance degradation period by detecting the need for adaptation before full re-convergence becomes necessary
Solution Approach 2:
The system changes its operational parameters based on detected echo gain changes. By monitoring specific signal parameters and comparing them against thresholds, the system can trigger parameter adjustments that enable faster adaptation to new echo characteristics, reducing the re-convergence time and maintaining better performance during the transition period
3Speed
If echo cancellers implement fast echo gain change detection with threshold comparison, then re-convergence speed is improved, but processing complexity increases
Solution Approach 1:
The system applies threshold comparison specifically to detect echo gain changes, rather than implementing complex processing across the entire signal processing chain. By localizing the complexity to a specific detection function that monitors particular signal characteristics, the system achieves fast re-convergence while minimizing overall processing complexity
Solution Approach 2:
The system performs partial monitoring of signal characteristics using simple threshold comparison, rather than implementing full-spectrum complex analysis. This partial action approach provides sufficient detection capability for echo gain changes while keeping processing complexity low, enabling fast re-convergence without excessive computational burden
Data Source
AI summary
An apparatus generally having a first circuit and a second circuit is disclosed. The first circuit may be configured to synthesize a first vector by filtering a second vector based on a third vector. The second circuit may be configured to (i) generate a gain corresponding to a fourth vector, (ii) compare the gain to a plurality of thresholds and (iii) update the third vector as a function of the gain where the compare determines that the gain is not between the thresholds. The fourth vector may be received from a network as an echo of the second vector.