Study On Signal Detection Method And Its Application Based On Correlative Theory

Weak signal detection has been widely used in industrial situations. While the technology of correlative detection, which is a crucial research direction of it, has good performance in magnifying available signal and attenuating noise. For the demand of low flowrate detection in electromagnetic flowmeter and fluidic flowmeter area, we apply the technology of correlative detection in this paper to improve the performance of these flowmeters. This application is of great value in market prospect. In this thesis, the following sections are introduced:1. The techonology of correlative detection, electromagnetic flowmeter and fluidic flowmeter was introduced. Meanwhile, an orthogonal correlative amplifier with 1KHZ center frequency was designed based on the principle of correlative detection. We do experiments on this amplifier to validate the performance of correlative detection. Also this amplifier can be used to measure 1KHZ weak signal.2. This paper successfully designed an intelligent electromagnetic flowmeter converter based on the principle of correlative detection, the functions of which include flowrate measurement, LCD display, IRDA communication with the computer, data storage. We developed hadware of the system, embedded software of MSP430 microprocessor and man-machine interface software on PC. Through the test on industrial caliberation equipment, we found that our flowmeter can measure the range from 0.013m/s to 4.42m/s. When the flowrate is zero, the flowmeter works well.3. The application of correlative detection on the fluidic flowmeter was proposed. Here we introduced the design which contains structural design and circuit design. In order to get flexible application, we designed a correlative amplifier with center frequency controllable. In the experiment we show that correlative detection can be used on fluidic flowmeter's weak signal detection.In the end, future work is pointed out.