Vortex shedding flow meter based on self-adaptive fast Fourier transformation

Abstract

The invention relates to a vortex shedding flow meter based on self-adaptive fast Fourier transformation, which comprises a charge amplifier, a first filter, a program-controlled voltage amplifier, a second filter, a program-controlled scmitt trigger, a bias voltage circuit, a singlechip computer, an LDO (Low Dropout Regulator) circuit, a reset circuit, a key input, a 4-20mA output circuit and an LCD (Liquid Crystal Display) circuit. A signal generated by a vortex shedding sensor is connected with the charge amplifier; the output of the charge amplifier is connected with the first filter; the output of the first filter is connected with the program-controlled voltage amplifier; the output of the program-controlled voltage amplifier is connected with the second filter; the output of the second filter is divided into two paths, wherein one path is connected with the singlechip computer; the other path is connected with the program-controlled scmitt trigger; and the program-controlled scmitt trigger is connected with the singlechip computer. According to the vortex shedding flow meter disclosed by the invention, various noises can be effectively inhibited and low-flow and high-precision measurement is realized, thereby the measuring range ratio is enlarged and the measuring precision and the sensitivity are improved.

Description

technical field [0001] The invention belongs to the technical field of electronic detection, mainly relates to a signal processing circuit and digital signal processing technology, and is a stress-type piezoelectric vortex flowmeter, especially a single-chip microcomputer (MCU)-based self-adaptive fast Fourier flowmeter. Signal processing system for stress-type piezoelectric vortex flowmeter with transform (FFT) power spectrum analysis. Background technique [0002] The stress-type vortex flowmeter based on the Karman vortex street principle has developed rapidly since it appeared in the late 1970s because of its high sensitivity, good stability, and low price. At present, most of the vortex flowmeters integrate the primary instrument and the secondary instrument, and are developing in the direction of integration and intelligence. However, the current smart vortex flowmeters in my country generally have the problems of undetectable signals and serious vibration and noise e...

AI Technical Summary

Problems solved by technology

In addition, when the vortex signal is shaped into a pulse signal preprocessing, it is usually realized by using a Schmitt trigger circuit, but a single threshold voltage cannot meet the requirements of system software and hardware variable parameters

[0004] At present, the method based on fast Fourier transform power spectrum analysis has been successfully applied in this technical field, but the minimum resolvable frequency is a fixed value in the entire range area, which leads to low resolution of the instrument at low flow rate and high resolution at high flow rate The problem

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