A measuring method of pwm wave duty cycle under the condition of industrial noise

Abstract

The invention discloses a PWM wave duty ratio measuring method under an industrial noise condition; the method comprises the following steps: acquiring PWM signal voltage instant values, limiting theamplitude of the acquired voltage instant value according to a set amplitude limiting threshold, obtaining the duty ratio of a to-be-detected periodic signal according to the mean value of a pluralityof acquired voltage instant values and the amplitude limiting threshold upper limit. The method can remove noise interferences on the signal in certain level through amplitude limiting, and employs ahigh voltage acquisition frequency to ensure the signal chip to track continuous changes of the duty ratio. The method uses the single chip to acquire voltage signals, and processes the voltage signals so as to obtain the duty ratio, thus measuring the duty ratio without using a high frequency sampling signal; the method solves the mean value of the voltage values measured in many times, thus further reducing errors.

Description

technical field [0001] The invention belongs to the technical field of signal testing, and in particular relates to a method for measuring the duty ratio of PWM waves under the condition of industrial noise. Background technique [0002] The duty cycle refers to the time ratio of the active level within one cycle. For example, the duty cycle of a square wave (a rectangular wave, that is, the waveform of voltage or current is rectangular) is 50%, indicating that the time occupied by the positive level is 0.5 period. Its meaning can be extended to the ratio of the duration of a certain phenomenon to the total time in a periodic phenomenon. [0003] At present, ordinary switch-type actuators can no longer meet the high-precision requirements of modern control systems. Duty cycle control, also known as electronically controlled pulse width modulation (PWM) technology, uses electronic control devices to modulate the pulse width of a voltage signal of a certain frequency applied...

AI Technical Summary

Problems solved by technology

[0012] Analog measurements are less sensitive when measuring continuously varying duty cycles

[0013] Existing measurement methods need to use sampling signals that are 2.56 to 4 times higher than the signal to be tested for frequency testing, which requires high testing equipment and limits the maximum testable frequency of the signal to be tested

Images