Based On The Emd Decomposition Level Of Non-stationary Signal Processing And Detection System Design

In this thesis, tank level as the object of study, increased or discharge of the liquid level in the tank liquid level signal is non-stationary level signal when the liquid level detection method for non-steady level signalthe detection is not accurate. Therefore, this paper focuses on the body’s level signal when the tank level signal instability is a non-stationary level signal detection, through the use of advanced electronic design technology and digital signal processing algorithms, developed a high precision, stable performance, intelligent detection system.Firstly, EMD empirical mode decomposition in the Hilbert Huang Transformed is researched and simulation, non-linear and non-stationary are non-stationary level signal features, EMD empirical to counter mode decomposition is used to bit the non-smooth liquid level signal into several intrinsic mode functions (IMF) in order to extract the liquid level signal characteristics and trends, and then to determine the actual level of non-stationary level signal value through the intrinsic mode functions (IMF). The experiments show that the EMD method is the best way to extract the signal trend or mean through the simulation results show that the actual level value is more accurate and more stable than that of EMD obtained without the decomposition level value.The object of this research is non-steady level signal, the entire system uses the SOPC system based on Nios ii soft-core processor, uses the Nios ii the internal configuration of the soft-core processor core and system common, the rich commonly standard IP core resources the system provided for non-stationary level signal detection and processing. Peripheral hardware circuit, includ:ultrasonic level acquisition circuit, keyboard input circuit, LCD level data show circuit, DS1302clock circuit, serial level data output circuit and USB level data output circuit, the system’s processor is the chip of Altera Corporation’s EP2C8Q208C8. The basic configurations of the SOPC system included:Nios ii soft-core processor, SDRAM external memory, the EPCS serial data configuration module, the system ID module and PLL module. The design of the software part of this thesis, includ the level signal acquisition module of EMD non-stationary signal processing module, the keyboard input module, the LCD level display module, DS1302clock module, serial and USB interface level data output module programming. The experimental results show that join the EMD level signal processing system that detecting the liquid level signal, it’s accuracy and stability should be higher than those not using this method the system.