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    A Real-time Pulse Generating Circuit
    Signal generating circuit is made up of single chip MSP430F149 and other related circuits, such as D/A converting circuit.
    In this paper, the main theory of DDS and the working principles of AD9850 are described at first, and then the generating circuit of a pulsed ultrasonic scanning waveform based on two AD9850s is introduced.
    A Pulse Generating Circuit in Positive and Negative Sequence
    A New Broadband Narrow Pulse Ultrasonic Generating Circuit
    The signal collecting system of singlechip collects the signals from generator. The paper introduces the every part of the singlechip. The key component is a 8051CPU, its surrounding circuits include DC power source, simulating signal collecting circuit, digital signal collecting circuit, A/D converting circuit, clock generating circuit, counting frequency circuit, controlling circuit, communicating circuit, and some other circuits.
    Subsequently, the disc type rotational armature generator and the rotational coupling transformer are separately leaded in to realize the power supplies of the carrier signal generating circuit and output of the measuring signal.
    Two different three-layer wavelet neural networks are constructed for DBD ozone generating circuit fault, and the mathematical model and learning arithmetic are given.
    针对DBD型臭氧发生电路故障,构造了激活函数型和权值型两种不同的三层小波神经网络,给出了相应的数学模型和学习算法,建立了小波神经网络的输出与故障元之间的对应关系,实现了电路的故障诊断,并与用普通BP网络诊断的结果进行了比较。 仿真结果验证了两种故障诊断方法的正确性和较好的准确性。
    Secondly, basing on analysis of Direct Digital Frequency Synthesis (DDS)’s principle, structure and its optimization, this paper designs a low power consumption, high stability DDS generating circuit to generate a sine wave as the driving source for inductive displacement transducer.
    The hardware system is mainly composed of sine wave source generating circuit, data acquisition and conversion circuit, TMS320F240 and its peripheral circuit, external memory circuit, 4x4 matrix keyboard circuit, LCD and serial communication circuit.
    Upon the radio frequency admittance capacitive level measurement, the analog, digital circuits and relevant program of the system have been designed, especially the design of sine waveform generating circuit, synchronization channels circuit and filter circuit in the analog system.
    For using the vector voltage/current method to measure impedance, we design the signal generating electro circuits and voltage/current sampling circuits. The signal generating circuit can produce sin wave signal within 0~2kHz for the impedance measuring in the different exciting signal source simulation using voltage/current method and for the frequency sweep signal mode.
    The mathematical relation formula is derived from the train running speed,distance and the output voltage frequency of tacho generator. The circuit diagram is given that realizes the relations by utilizing the principle of CMOS digital integrated circuit and frequency composition. Analysis and illustration are made regarding interface circuit,wheel diameter input method,frequency composition circuit,frequency dividing circuit,BCD proportion multiplier circuit,display circuit,base frequency generating circuit and power supply circuit.
    Basing on the theory of digital synchronizer, we analyze the character of GMSK signals in this paper, and design a practical and easily realized arithmetic of bit synchronization and integral detection. Basing on the theory of successive approximation A/D converter, with the external sawtooth wave generating circuit and the comparator in the SingleChip, We accomplished A/D convert by program.
    本文从 GMSK调制解调原理出发 ,分析了 GMSK信号的特征 ,依据数字同步器原理 ,提出了实用的比特跟踪同步和积分判决算法 ,并依照逐次逼近 A/ D转换器的原理 ,通过外部锯齿波发生电路 ,配合单片机内部的比较器和相关程序完成了输入信号的 A/ D转换 ,用单片机实现了 GMSK软件解调。
    The input isde is a PFC circuit with 400V DC voltage, with a full-bridge MOSFET inverter circuit, at the fixed-frequency PWM generating circuit and IR2110 driving circuit, the input DC voltage is changed to high frequency AC voltage, by only one resonant inductor, the MOSFET can achieve the zero voltage turn-on, this greatly decreases the switching lose and the switching noise.
    本电源由PFC电路提供 40 0V的高压直流输入 ,再由MOSFET组成全桥逆变电路 ,在固定频率的PWM发生电路和IR2 110MOSFET驱动电路作用下 ,只加一个谐振电感就可实现开关管的零电压开通 ,可在大大降低开关损耗和噪声的同时实现直流交流的变换。
    Based on the new method, a battery internal resistance intelligent measuring instrument was designed. Its main controller is ADuC 812 MCU and some advanced chips are adopted in its signal generating circuit and signal sample converting circuit. The frequency and amplitude of its AC signal could be properly adjusted according to battery's type and working environment.
    在新方法的基础上设计了蓄电池内阻智能测试仪,该仪器以ADuC 812单片机作为主控芯片,采用了新型信号发生电路和信号采样转换电路,可根据被测蓄电池型号和工作环境的不同适时改变交流信号的频率和幅值,并能与上位机进行通信。
    In order to reduce the cost and power of the system,this paper samples the high frequency sygnal(6.25MHz~100MHz)equivalently based on the precision clock generating circuit,and designs high speed circuit,AD,FIFO and FPGA etc. and implements a portable memoryoscillograph.
    Triggered vacuum switches(TVS) are used as closing switches in the study. A three-electrode-gap is used in the high voltage trigger pulse generating circuit to acquire a steepened high voltage trigger pulse,so as to ensure that the accuracy of delay time of TVS switching to outer control signal is controlled within 1μs.
    HFBR-0400 series of fiber optic transmitters and receivers are used in the trigger signal generating circuit to improve the ability to inhibit interference. Mis-triggering because of mutual interferences among stages is solved in the experiments of multi-stage launch.


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