Sampling Rate Mismatch Correction for Echo Cancellation
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Solution Overview
Problem
Existing methods for sampling rate mismatch correction in echo cancellation require high hardware performance, complex calculations, and burden the echo cancellation system, as they do not directly correct the signals, leading to reduced echo cancellation performance.
Innovation Solution
A method and system that calculate the transfer function of receiving terminal signals relative to transmitting terminal signals to obtain transmission time delays, fit sampling rate mismatches using a linear relationship, and adjust sampling rates in real-time to correct mismatches before echo cancellation, using a system comprising a time delay estimator, sampling rate mismatch estimator, and sampling rate adjustor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the existing practice of monitoring sampling clocks and using statistics of sampling clock cycles is used to calculate sampling rate mismatch, then the sampling rate mismatch can be calculated, but it requires high hardware performance (CPU with high-qualified performance) and complex calculations
Solution Approach 1:
The patent extracts the essential information needed for sampling rate mismatch calculation directly from the audio signals themselves, rather than monitoring separate sampling clock signals. By using the audio signals' inherent timing characteristics and transfer function analysis, the method obtains sampling rate mismatch information without requiring additional clock monitoring hardware or complex clock cycle statistics calculation.
Solution Approach 2:
The patent introduces a transfer function as an intermediary to relate the transmitting terminal signal and receiving terminal signal. This transfer function serves as a mediator that connects the two signals and enables the calculation of sampling rate mismatch through their relationship, avoiding the need to directly monitor and compare sampling clocks from different sources.
2Measurement precision
If the existing practice of using statistics of sampling clock cycles or pure algorithm approach is used, then the sampling rate mismatch can be calculated, but more storage resources are occupied and calculations are more complicated
Solution Approach 1:
The patent uses partial action by focusing only on the essential timing relationship between transmitting and receiving signals through transfer function analysis. Instead of processing complete sampling clock cycle statistics or using complex pure algorithm approaches within pre-set variation ranges, the method selectively extracts and processes only the necessary timing information from the audio signals, reducing storage requirements while maintaining calculation accuracy.
3Reliability
If the sampling rate mismatch is transmitted to an echo cancellation system for adjustment and processing, then the sampling rate mismatch correction can be achieved, but the burden of the system increases and the echo cancellation effect is affected
Solution Approach 1:
The patent performs preliminary action by calculating and correcting the sampling rate mismatch before the echo cancellation process. The method first determines the sampling rate mismatch using transfer function analysis, then applies correction to align the sampling rates of transmitting and receiving signals. This preliminary correction ensures that the subsequent echo cancellation operates on properly synchronized signals, improving effectiveness while reducing the processing burden on the echo cancellation system itself.
Data Source
AI summary
Disclosed in the invention is a method and system for sampling rate mismatch correction of transmitting and receiving terminals, which can obtain a high-precision sampling rate mismatch in real time, carry out sampling rate correction on transmitting and receiving terminal signals, and send the transmitting terminal signal and the receiving terminal signal that have the same sampling rate after corrected to an echo cancellation system to carry out echo cancellation. The present invention can improve the quality of echo cancellation, simplify the computation and reduce the cost. The method for sampling rate mismatch correction of transmitting and receiving terminals provided in the embodiments of the invention comprises: calculating a transfer function of a receiving terminal signal relative to a transmitting terminal signal at each sampling timing according to the transmitting and receiving terminal signals; obtaining a transmission time delay of the transmitting and receiving terminals at each sampling timing using the transfer function; obtaining a sampling rate mismatch of the transmitting and receiving terminals at each sampling timing by means of parameter fitting using the transmission time delay and the linear relationship between the transmission time delay and the sampling rate mismatch; and adjusting the sampling rate of the transmitting terminal signal or the receiving terminal signal at each sampling timing according to the sampling rate mismatch.