Design Of Nanosecond Square Pulse And Damped Sine Pulse Generator

Electromagnetic pulse (EMP) is a transient electromagnetic phenomenon. Seen from time domain, the rising edge of nanosecond pulse is very steep. Meanwhile the band-width of nanosecond pulse is very wide in frequency domain. This is the focus and also difficulty of electric signal measurement techniques. Electromagnetic pulse can influence or destroy electronic parts, circuits and equipments through various coupling ways.The theory of EMP simulator was introduced. The design of the signal generator of square wave pulse and damped sinusoidal transient signal and the pulse measurement of high voltage were discussed and analyzed by simulation and experiment. The main contents of this paper are listed as following:1. The condition of the uneven distributed parameters of the transmission line has been modeled and analyzed in the paper based on transmission line theory. Including the continuity of the voltage and current conditions, the refraction and reflection of electromagnetic waves in the transmission line connection point, the condition that a charged transmission line discharges to another transmission line with the ideal switch, and a ideal switch connected to the two-stage charged transmission line.2. In this paper, spectrum analysis of the damped sinusoidal transient signal has been done. spectrum analysis. A damped sinusoidal transient signals can be generated in the test harness with the form of capacitor discharging to the mutual inductance circuit. Transmission line effects of drive cable must be considered at a higher frequency point.3. Measurement and analysis of the signal source is conducted and analyzed combined with the high voltage power supply, the attenuator, the load, oscilloscope, etc. According to the result of the running test of the production of the signal generator, check the parameter of the circuit inductors, the resistors and the capacitance so that the signal waveform of the generator could be further optimized.The main results or conclusion obtained from thsis researchs are listed as follow:1. The results of the simulation showed that the damped sinusoidal transient signals were in the peak energy at the frequency point. In frequency spectrum, the signal at the low frequency attenuations relatively slow and extended to a DC component, while at the high frequency, however, is the rapid decay. The signal energy decay faster more concentrated in the frequency point.2、Pulse rise time decreases with the increase of the turn-on voltage, but in the process of reduced did not show obvious regularity. And the influences of spark resistance and inductance on pulse risetime can not be ignored.3、In the case where the load mismatch of the test system, the pulse signals reflection and refraction and irregularities in the transmission process happened. And the signal had a greater volatility and lower transmission efficiency.The experimental values of this signal generator are consistent with the theoretical values. The rise-time of the square wave pulse can be as short as1.4ns and the delay time34.6ns. In10kHz,100kHz,1MHz,10MHz,30MHz frequency point, ideal damped sinusoidal signals could got from the test system.