Hysteresis comparison circuit for automatic gain adjustment of gas ultrasonic flowmeter and implementation method

Abstract

The invention discloses a hysteresis comparison circuit for automatic gain adjustment of a gas ultrasonic flowmeter and an implementation method. The hysteresis comparison circuit comprises a high threshold detection circuit and a low threshold detection circuit. Through adoption of the method, the echo amplitude can be determined to be a high value which just exceeds a high threshold value aftergain adjustment is completed, the echo amplitude after adjustment is ensured not to appear at a position close to a low threshold, the problem of frequent adjustment due to the fact that the amplitudeafter adjustment appears at a critical position close to the low threshold is solved, whether the amplitude just exceeds a high value of the high threshold value or not is judged regularly, and the echo amplitude is ensured not to generate a condition of wrong waves due to over-high amplitude. According to the method, the echo amplitude is controlled within a determined range; meanwhile, due to the fact that hysteresis comparison is added, when the signal descending range does not exceed a low threshold value, gain adjustment cannot be caused, the problem of frequent adjustment caused by signal fluctuation can be effectively solved, the amplitude of echo signals in reliable measurement is guaranteed, the measurement accuracy is improved, and power consumption is effectively reduced.

Description

technical field [0001] The invention relates to a hysteresis comparator circuit and a realization method for automatic gain adjustment of a gas ultrasonic flowmeter, which are used for determining the gain value during the automatic gain adjustment process of the gas ultrasonic flowmeter. Background technique [0002] The original echo signal of the gas ultrasonic flowmeter will fluctuate greatly due to changes in pressure, flow rate, etc. In order to adapt to this fluctuation, an automatic gain adjustment circuit is needed to ensure that the Get a relatively stable echo signal. The method of detecting the echo with the threshold voltage is to compare the echo signal with the threshold voltage to determine the echo position. In order to ensure that each echo position is determined, that is, no wrong wave occurs, it is necessary to ensure the echo signal Amplitude, that is, when the signal amplitude is lower than the set value, it needs to be enlarged and adjusted to be grea...

AI Technical Summary

Problems solved by technology

Make sure that the echo amplitude is a high value that just exceeds the high threshold after the gain adjustment is completed, so as to ensure that the echo amplitude after the adjustment will not appear near the low threshold, and solve the problem that the amplitude appears close to the low threshold after the adjustment is completed. The problem of frequent adjustment of the critical position, and at the same time regularly judge whether it is a high value that just exceeds the high threshold, so as to ensure that the echo amplitude will not cause wrong waves due to too high

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