An error-proof wave signal processing circuit for a gas ultrasonic flowmeter

Abstract

The invention discloses an anti-error wave signal processing circuit of a gas ultrasonic flowmeter. The anti-error wave signal processing circuit comprises: an ultrasonic receiving transducer used forreceiving an ultrasonic signal; a controllable gain amplifying circuit connected to the ultrasonic receiving transducer; an analog to digital conversion circuit connected to the controllable gain amplifying circuit; a dual threshold detection circuit connected to the controllable gain amplifying circuit; a peak hold circuit connected to the controllable gain amplifying circuit; a programmable multi-threshold comparison circuit connected to the peak hold circuit; a wave selection circuit respectively connected to the dual threshold detection circuit and the programmable multi-threshold comparison circuit; and a timing circuit connected to the wave selection circuit. According to the anti-error wave signal processing circuit of the gas ultrasonic flowmeter, the error wave interference existing when the transit time of the ultrasonic signal is measured by a threshold detection method can be directly eliminated, so that the measurement accuracy and stability of the transit time are effectively improved, and the measurement accuracy and stability of the ultrasonic flowmeter are improved.

Description

technical field [0001] The invention relates to the technical field of flow detection, in particular to an anti-error wave signal processing circuit of a gas ultrasonic flowmeter. Background technique [0002] At present, the gas ultrasonic flowmeter has many advantages such as large range ratio, high measurement accuracy, no pressure loss, etc., especially in the measurement of large-caliber natural gas flow, it has unique advantages. The measurement principle of the gas ultrasonic flowmeter is divided into the propagation velocity difference method and the Doppler method. Propagation time difference method can be divided into time difference method, phase difference method and frequency difference method, among them, time difference method has good effect and is most widely used in gas ultrasonic flowmeter. When the gas ultrasonic flowmeter based on the measurement principle of the time difference method measures the gas flow, firstly, according to the inverse piezoelectr...

AI Technical Summary

Problems solved by technology

However, the energy attenuation of the ultrasonic signal in the gas medium is serious, and the echo signal has problems such as weak amplitude, low signal-to-noise ratio, and susceptibility to interference. As the flow rate increases, these problems are very serious

When the signal is attenuated or increased due to interference, it is likely to cause the corresponding waveform of the received signal to exceed the detection range of the threshold voltage, which is manifested as a wave error phenomenon, such as figure 1 shown

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