Concrete mixture moisture content measuring device and method based on TDT (Time Domain Transmissometry) and phase comparison

Abstract

The invention discloses an accurate concrete mixture moisture content measuring device and an accurate concrete mixture moisture content measuring method based on TDT (Time Domain Transmissometry) andphase comparison. The mixture moisture content is indirectly obtained according to the dielectric constant of a medium, and the dielectric constant of the medium is obtained during measurement of transmission of an electromagnetic wave signal along a transmission line placed in the medium; and during transmission of an electromagnetic wave along a TDT probe, the tail end of the probe is not open,so that a signal after one-way transmission of the electromagnetic wave is only required to be detected, while detection on a reflected signal is not specified. Based on such a principle, due to transmission delay during transmission of the electromagnetic wave in the medium, by a phase comparison method, a delay measurement circuit is designed through an AD8302 integrated chip, and the delay measurement circuit is integrated with the sensor probe, so that an analog quantity and a digital quantity can be output, the measurement accuracy is significantly improved, and the cost is much lower than that of TDT sensor equipment of the same type; and the concrete mixture moisture content measuring device has very good application and popularization prospects.

Description

technical field [0001] The invention belongs to the technical field of circuit and information processing in electronic information, especially belongs to the technical field of electromagnetic wave transmission time domain on a transmission line, and relates to a precise measurement device for moisture content of concrete mixture based on TDT and phase comparison and its method. Background technique [0002] Scholar Chernyak first systematically studied the dielectric properties of soil, and his "Research Method for Dielectric Properties of Wet Soil" enabled soil physicists to have a holistic understanding of soil dielectric physical behavior for the first time. The theory of dielectric properties of soil can be applied to the measurement of moisture content of concrete mixture. According to the principle and implementation path, the dielectric characteristic method can be roughly divided into the following types: the principle of time domain reflection or transmission vec...

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Problems solved by technology

The disadvantage of the sensor based on the principle of AC capacitive reactance is that the working frequency is relatively low, and the performance of the sensor is easily affected by external factors, such as temperature, conductivity of the medium, etc.

[0006] It is basically difficult to maintain a balance between accuracy and design cost for the sensors currently in use. Therefore, it is urgent to find a sensor with advanced principles, simple circuits, high measurement accuracy, good repeatability, strong adaptability to dry hard concrete mixtures, and low cost. Circuit Design Method for Inexpensive Sensors

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