Selection Of Waveform Research Articles

The p+n−n+ diode pulsed at extreme current densities—I : Numerical techniques and reverse pulsed case

The anomalous voltage transient response of the p + n − n + diode structure to a single non-repetitive intense current pulse is presented for current densities up to and greater than 10 4 amp/cm 2. A very general device model and an accurate numerical iterative method are used to solve the basic transport equations leaving the selection of pulse wave form, generation-recombination laws, avalanching, doping profiles, mobility, and injection levels arbitrary. The boundary conditions are applied solely to the external contacts. In order to achieve numerical convergence to such a nonlinear problem, due to the extreme currents, it was determined that a very accurate thermal equilibrium solution was necessary. Two examples for the reverse pulse case, reach-through and avalanche, are presented to show the effects of large current densities on the reverse voltage response.

On the selection of the supply voltage waveform in induction motor drives

SUMMARY When the induction motors are supplied by static inverters alternating currents in the d.c. supply of the inverter are produced. In some applications it is necessary to satisfy prefixed constraints on the amplitude and bandwidth of these alternating currents. A new procedure is proposed for selecting the pulse width modulated waveform of the a.c. voltages in a three-phase bridge inverter supplied by a d.c. voltage of constant amplitude. A method is developed for calculating in the steady state the harmonic content of the d.c. supply current for a given pulse width modulated a.c. voltage waveform. The proposed procedure is applied to a problem with particular constraints on the harmonic content.

Selection of source-modulation waveform for improved signal-to-noise ratio in atomic absorption spectrometry

Selection of source-modulation waveform for improved signal-to-noise ratio in atomic absorption spectrometry