Audio Watermark Echo Cancellation for Conference Terminals
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Solution Overview
Problem
Existing echo cancellation methods in voice conferences face challenges with unstable feedback mechanisms and changing device positions, leading to delayed convergence and poor echo cancellation performance.
Innovation Solution
The use of a synthetic speech signal incorporating an audio watermark signal allows for the detection of delay times, enabling efficient echo cancellation by using a known and fixed audio watermark signal to reduce convergence time and prevent the watermark from being heard by users.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional echo cancellation algorithms are used, then echo cancellation is achieved, but convergence time is long and performance is poor when device positions change
Solution Approach 1:
The patent applies preliminary action by embedding an audio watermark signal in advance into the speech signal before transmission. This watermark serves as a known reference that enables the receiving end to quickly determine delay times and accelerate the echo cancellation convergence process, solving the problem of long convergence time in traditional methods.
Solution Approach 2:
The audio watermark signal acts as an intermediary element between the transmitting and receiving ends. It provides a known reference signal that facilitates the calculation of delay times and improves the reliability of echo cancellation, especially when device positions change and cause unstable feedback mechanisms.
2Loss of time
If audio watermark signal is used for echo cancellation, then convergence time is reduced, but there is risk that users may hear the watermark
Solution Approach 1:
The patent applies parameter changes by modifying the frequency parameters of the audio watermark signal. The watermark is designed to operate in frequency ranges that are imperceptible to human ears, typically ultrasonic frequencies above 20kHz, thus reducing convergence time while preventing users from hearing the watermark signal.
3Adaptability or versatility
If microphones receive sounds from multiple speakers, then conference participation is enabled, but unstable feedback mechanisms and howling occur
Solution Approach 1:
The patent applies feedback control by using the embedded audio watermark as a reference signal to continuously monitor and calculate echo paths. This enables the system to dynamically adjust echo cancellation parameters in real-time, suppressing feedback and howling while maintaining multi-device conference participation capability.
Data Source
AI summary
A conference terminal and an echo cancellation method for a conference are provided. In the echo cancellation method, a synthetic speech signal is received. The synthetic speech signal includes a user speech signal of a speaking party corresponding to a first conference terminal of multiple conference terminals and an audio watermark signal corresponding to the first conference terminal. One or more delay times corresponding to the audio watermark signal are detected in a received audio signal. The received audio signal is recorded through a sound receiver of a second conference terminal of the conference terminals. An echo in the received audio signal is canceled according to the delay time.