Digital multimeter de-noising method based on FIR (Finite Impulse Response) filter

Abstract

The invention discloses a digital multimeter de-noising method based on an FIR (Finite Impulse Response) filter. The method comprises the following steps: performing filtering and de-noising in a digital multimeter measuring circuit through an FIR filter measuring signal; during initialization of a digital multimeter, designing FIR filters on measuring levels through an FIR filter design method based on a particle swarm algorithm, specifically: designing a fitness function of the particle swarm algorithm based on signal-to-noise ratios of filtered signals of the FIR filters and mean square errors of the FIR filters by taking unit impulse responses of the FIR filters as particle position vectors of the particle swarm algorithm, and performing iteration to obtain an FIR filter; and during actual measurement of the digital multimeter, monitoring the signal-to-noise ratios of the filtered signals, performing re-optimization when the signal-to-noise ratios are greater than a threshold value, and updating the FIR filter. Through adoption of the digital multimeter de-noising method, the FIR filter in which the signal-to-noise ratio performance is considered can be obtained; adjustment of the adaptability of the FIR filter to an input signal is realized during use of the digital multimeter; and the de-noising performance of the digital multimeter is improved.

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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