Filtering device inhibition effect evaluation method based on signal characteristic calculation

Abstract

The embodiment of the invention discloses a filtering device inhibition effect evaluation method based on signal feature calculation, and relates to the technical field of signal testing. The method comprises the steps: obtaining a to-be-evaluated input signal and a distortion signal generated after the input signal passes through a filtering device; respectively calculating a maximum value, a minimum value, signal energy and trend correlation of waveforms of the input signal and the distortion signal in a time domain range; forming a disturbance similarity calculation formula based on the ratios of the input signal and the distortion signal on the aspects of the maximum value, the minimum value, the signal energy and the trend correlation; based on a calculation result obtained by the disturbance similarity calculation formula, evaluating the inhibition effect of the filter device. According to the method disclosed in the scheme of the embodiment of the invention, the inhibition effect of the filtering device can be evaluated in a quantification mode.

Description

Technical field [0001] The present invention relates to signal testing technology, and particularly relates to a filter member inhibition evaluation method based on the calculated signal characteristics. Background technique [0002] Current national standard GB / T 7343-2017 "Measurement method of inhibiting characteristics of the passive EMC filter member" provides an insertion loss of passive filter components, and the impedance measuring S parameter method, three or more test parameters are frequency domain, similar measurements can be assessed within a band filter member inhibiting properties, but not the direct effect of the filter member effectively suppressed disturbance signal in the time domain. [0003] Standard test method is to use a calibrated 50Ω 50Ω signal generator and a receiver, the insertion loss obtained by the following formula: [0004] a e = 20log (V 0 / 2V 2 ) [0005] a e Insertion loss in decibels (dB) and the [0006] V 0 50Ω open circuit voltage signa...

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Problems solved by technology

[0011] 1. In the product design stage, since there is no quantified filter device inhibition index, in many cases, equipment manufacturers often can only select several suitable filter devices based on the insertion loss or cut-off frequency of the filter device, and then pass the actual test in the laboratory. Investigate the suppression effect of filter devices on sensitive time-domain disturbance signals, which will increase the design cost and time cost of equipment manufacturers;

[0012] 2. In the stage of product finalization, it is not easy to find individual differences in the suppression characteristics of filter components in the bulk purchase of filter components, which leads to unqualified phenomena in the electromagnetic immunity test of product sampling;

[0013] 3. The passive filter device parameters specified in the standard include insertion loss, impedance and S parameters, all of which are frequency domain parameters. In the face of time domain disturbance signals, the above parameters cannot directly evaluate the suppression effect of the filter device

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