| With the needs of high-speed information transmission and processing for modern society, high-speed electrical pulse technology has been developed. In recent years, as radar, microwave pulse power, ultra-wideband communications and the rapid development of high power microwave, the indicator requirement of ultrashort optical pulses become much higher. As we know, the ultrashort optical pulses not only need super power but also need narrow pulse width that can bear intense voltage. Therefore, this generation has put forward higher requirements to the ultrashort pulse.High-speed electrical pulse is applied extensively, in military or civilian all have very broad application prospects. In the key technology of UWB communications, the formation of circuits of the narrow pulse signal has a critical field of RF technical problems. In addition, high-speed electrical pulse plays an important role in the pulse-driven power semiconductor lasers, to the electric injection semiconductor lasers,the core part of its driven circuit is the pulse circuit and power amplifier circuit. Currently, the high-speed electrical pulse mainly includes two ways, one is to apply the switching characteristics, which is to use ultrashort laser pulses to trigger photoconductive switch, so as to lead to instant breakover and generates a short pulse current,the other is make use of nonlinear switching characteristics of semiconductor devices to generate high-speed electrical pulse. Based on the devices'characteristics and requirements of the pulse parameters, this paper selected the avalanche transistor as a core device; used the avalanche effect theory to design a short rise time and pulse width, with periodic, frequency adjustable pulse circuit. The system is composed by the trigger pulse circuit, pulse shaping circuits and high-speed narrow pulse forming circuit, and be carried out simulation, We can infer from the result that the amplitude and width of Output pulse is contradictorily, these two can not simultaneously achieve the best results, therefore, on condition that to ensure that front-end circuit, we should select a compromise value of Vcc and C. It was proved that the experimental results bring into correspondence with theoretical analysis and simulation analysis, but also had the relative error, for two reasons, one is the devices are common devices, and the welding circuit has effect on the result. Moreover, the oscilloscope measurement bandwidth is not enough, the measurement to rising edge of the pulse brought losses. Hence, the actual pulse and observed pulse has been out of shape. Secondly, this paper also analyzed time domain and frequency domain to pulse signals, focusing on parameters problems of the electrical pulse signal in time domain and frequency domain. For time-domain analysis of pulse signals, which include the following aspects: pulse amplitude, rise time, fall time, pulse width, pre-washed, overshoot and periodicity. Optical pulse signal in time domain analysis directly solved the system of differential, integral equation without any change. By using a time domain method and the convolution method to compute and analyze the system, and all the analysis and calculation are carried out within time variables, which involves the advantages that of intuitive and physical.In the frequency domain measurement, the measurement process must be carried out in the steady status without considering the impact of the time, as known as the steady-state measurement. To the Calculation for signal analysis, we often use differential equation, however, it becomes the algebraic equation to solve them easily can be seen that how the spectrum amplitude and phase respond with the frequency change by using Fourier and Laplace transform, you can also find the system cutoff frequency.Besides, comparing the time domain with frequency domain analysis, time-domain measurements and frequency domain measurements only has each other correspondence. In this domain measurements can be obtained through the conversion result to another field. In actual measurement, the two methods have their own scope of application and the corresponding measuring instruments. Oscilloscope is the time-domain measurement instruments used to facilitate measurement of waveform parameters, the phase relationship and time relationships. Spectrum analyzer is a frequency domain measurement instruments used to facilitate measurement of the spectrum, harmonic distortion, intermodulation, etc.. Later on it began its analysis to measurement, then studied on measurement method of the time domain and frequency domain on high-speed electric pulse, and discussed the attentive questions in the measurement.Pulses in time domain measurements used to measure pulse rate, so as to arrive at other time domain parameters. There are several methods for measuring the pulse in time domain: using oscilloscope to measure, using measure pulse rate and using sampling digital multimeter. According to the needs of practical applications, the frequency domain analysis, measurement object and purpose have nothing in common with each other, basically as following: the measurement of frequency characteristics, frequency selective measurement, spectrum analysis, modulation measurement, and harmonic distortion measurement. There are several ways of Frequency measurement of linear systems: point-frequency measurement, sweep-frequency measurements, multi-frequency measurement and broad-spectrum measurement. The spectrum measurement methods and equipment including: heterodyne harmonic analyzer, spectrum analyzer and calculation method.With the development of science and technology, especially in some special measurements such as optical communications, were raised to more stringent requirements for technical and precise pulse test. In addition to need for more rigorous and precise measurement of pulse amplitude signal, width, rise time, impulse and sag, the technology to use the pulse as measuring network and system for reflection and transmission characteristics also have been continuously improved. |
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