Zero-Phase Online DC-Removing Filter for Active Road Noise Control System

Abstract

The invention relates to a zero-phase on-line DC removal filter for a road noise active control system. The zero-phase on-line DC removal filter comprises a first delayer, wherein the first delayer isused for delaying an input signal x(n) by fs unit lengths to obtain a delay signal x(n-fs); a first subtracter, taking an input signal x (n) and a delay signal x (n-fs) as input and subtracting the input signal x (n) and the delay signal x (n-fs) to obtain an output difference signal w (n); a first adder, taking the difference signal w (n) and the intermediate delay signal r (n-1) as input and adding the input to obtain an intermediate signal r (n); a second delayer, used for delaying the intermediate signal r (n) by one unit length; and a first multiplier, used for dividing the intermediatesignal r (n) by the sampling frequency fs to obtain an average value of the input signal x (n), and a second subtracter, used for subtracting the input signal x (n) from the average value to obtain adirect-current-removed output signal y (n). Compared with the prior art, the zero-phase on-line DC removal filter can realize online DC component removal, does not introduce phase change, and is suitable for online removal of DC components in active noise control.

Description

Technical field [0001] The present invention relates to the field of digital signal processing, and more particularly to a zero phase line-dedicated filter for road noise active control systems. Background technique [0002] In the noise active control system, due to the self-characteristics of the sensor and hardware, the introduction of the DC component is measured when the reference signal and the error signal are measured. The mainstream algorithm of the noise active control system is the LMS algorithm. Due to the introduction of DC components, the algorithm will increase more and more in the process of iteration, so that the system cannot converge. [0003] Although the digital filter from MATLAB can be filtered out of the DC component, the phase difference is introduced, making the disclosure of the reference signal and the noise signal change, thereby reducing noise reduction amount, or even deinterlerges the system. Inventive content [0004] It is an object of the prese...

AI Technical Summary

Problems solved by technology

Due to the introduction of the DC component, the algorithm will accumulate more and more energy during the iterative process, so that the system cannot converge

[0003] Although the built-in digital filter in Matlab can filter out the DC component, it also introduces a phase difference, which changes the coherence between the reference signal and the noise signal, thereby reducing the amount of noise reduction and even causing the system to diverge.

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