Design And Implementation Of50-4000HZ Sine Wave Signal Power

Linear variable differential transformer(LVDT) is one of electromechanical sensor which has high stability and accuracy. For its superior performances, LVDT has already been widely used in aeronautic and aerospace field. It must be offered sine wave excitation signal by external devices in LVDT’s production testing and working time. However, the traditional signal generators have the shortcomings about low output voltage, week load capacity. They can not steady voltage and frequency. These drawbacks have greatly reduced LVDT’s working performance. This subject design a sine wave excitation signal generator with high stability and accuracy. Outputs voltage rms at40V and dual channel load current at2A, which offers excitation signal to LVDT.The main contributions of this subject are:(1) According to the characteristics of a linear system, we combine a principle of least jsquares fitting with PID control to fit open loop curve and closed loop curve. These open loop curves and closed loop curves are used for open loop control.Moreover, the method of window function which is used for filter processing has been adopted in this paper.(2) Using ALTERA FPGA and ARM Cortex-M3as the cores for cortrolling the system signals is proposed. The design of DDS with FPGA is adopt, and we use this DDS to output sine wave excitation signal combine to a16bit DAC named AD5445. Using Cortex-M3to achieve the controlling of power amplifier, closed feedback circuit, and man-computer interaction. It shows that the scheme is feasible.(3) This subject designs a system hardware based on DC-power module,signal control module,power amplifier module,feed back module and the man-computer interaction modules. Hardware circuit employs Candence and Multisim to conduct stimulation. It uses embedded C language to design the system software based on the main task, self-diagnosis task and maintenance task under IAR Embedded Workbench for ARM6.40. Through the cooperation of the software and the hardware, system testing and error analysis, the designing idea of this project is realized, rudimentarily achieving the designing demand of this project. Meanwhile, this paper also points out the design limitations and raises a claim for further study.