Noise reduction method of digital multimeter based on fir filter

Abstract

The invention discloses a FIR filter-based digital multimeter noise reduction method. In the digital multimeter measurement circuit, the FIR filter measurement signal is used for filtering and noise reduction; when the digital multimeter is initialized, the FIR filter based on the particle swarm algorithm is respectively used The FIR filter design method for each measurement gear is designed. The specific method is as follows: the unit impulse response of the FIR filter is used as the particle position vector of the particle swarm optimization algorithm, and the signal-to-noise value of the filtered signal based on the FIR filter The fitness function of the particle swarm algorithm is designed by using the ratio and the mean square error of the FIR filter, and the FIR filter is obtained iteratively; The FIR filter is updated. The invention can obtain the FIR filter taking into account the performance of the signal-to-noise ratio, realizes the adaptive adjustment of the FIR filter to the input signal during the use of the digital multimeter, and improves the noise reduction performance of the digital multimeter.

Description

technical field [0001] The invention belongs to the technical field of digital multimeters, and more specifically relates to a noise reduction method for digital multimeters based on an FIR filter. Background technique [0002] FIR (Finite Impulse Response, finite-length unit impulse response) filter, also known as a non-recursive filter, is the most basic component in a digital signal processing system. It can guarantee any amplitude-frequency characteristics while having strict linear phase frequency characteristics, and its unit sampling response is finite, so the filter is a stable system. Therefore, FIR filters are widely used in communication, image processing, pattern recognition and other fields. [0003] At present, the commonly used FIR filter design methods include window function method, frequency sampling method and optimal design method of ripple approximation such as Chebyshev. In practical engineering applications, the design and implementation of FIR filte...

AI Technical Summary

Problems solved by technology

In the digital multimeters that used FIR filters for noise reduction in the past, the FIR filter used a design algorithm to obtain an optimal FIR filter. During the use of the digital multimeter, the parameters of the FIR filter are fixed, and it is difficult to meet different measurement requirements. Practical requirements for changes in bit and input signal characteristics

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