Echo signal detection circuit of adaptive ultrasonic wave

Abstract

The invention discloses an echo signal detection circuit of an adaptive ultrasonic wave, wherein an echo signal docked by a pre-channel circuit is amplified and filtered, and a main channel circuit performs re-amplification processing and zero-crossing comparison to generate a main channel signal containing an interference pulse; an auxiliary channel circuit pre-receives the signal for peak detection and obtains a comparison level through attenuation according to a certain proportion, the official received signal is subjected with trigger comparison with the comparison level to generate a first pulse-sequence signal, a strobe signal is generated according to the falling edge of the first pulse for an AND-operation with the main channel signal, and a second pulse-sequence signal is output to trigger a timing module to stop timing to obtain a time difference. By adopting a peak detection circuit and cooperating with a working mode of two consecutive times of signal reception and transmission, the echo signal detection circuit provided by the invention dynamically tracks the pre-received signal and flexibly adjusts the comparison level, which solves the pulse-sequence skipping problem. In addition, the strobe signal is functioned to avoid the effect of the noise pulse of the main channel on the time measurement, and the main channel uses a zero-crossing comparator to solve the problem of phase lead or lag in the quarter period of the pulse sequence.

Description

technical field [0001] The invention belongs to the technical field of ultrasonic gas flow measurement, and more specifically relates to an adaptive ultrasonic echo signal detection circuit. Background technique [0002] In recent years, the ultrasonic gas flow measurement technology has developed rapidly, which has driven the rapid development of the ultrasonic gas flow meter industry. Compared with traditional flowmeters, ultrasonic gas flowmeters have many advantages such as wide measurement range, high precision, and strong stability, and are very suitable for industrial and civil gas measurement. [0003] The accuracy of the instantaneous flow rate of the ultrasonic gas flowmeter based on the time difference method mainly depends on the accuracy of measuring the time of the echo signal. In ultrasonic gas flow measurement, with the continuous increase of gas flow velocity and the uneven flow field of pipelines and other factors, the received echo signal will be attenuat...

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Problems solved by technology

[0010] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an adaptive ultrasonic echo signal detection circuit, which solves the problem of burst wave skipping by using the auxiliary channel circuit and the main channel circuit to process the received echo signal and the issue of the pulse train being phase-leading or lagging within a quarter of a cycle

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