Creation and FFT Analysis of Periodic Waveform

Abstract

We created periodically varying waveforms, which are rectangular, trapezoidal, triangular, and quasi-sinusoidal waveforms, by using the originally presented equations and we have investigated the effect of waveform on the frequency characteristics by FFT analysis. Under a excitation vibration having a symmetric quasi-sinusoidal waveform, the fundamental frequency of the system and frequencies at its odd numbered cycles appear. The fundamental frequency of the system and its integral-multiple frequencies appear under excitation vibration having an asymmetric quasi-sinusoidal waveform with the peaks shifted to right or left. Under vibration having a quasi-sinusoidal waveform, an angular frequency of 1 appears in addition to the excitation frequency when damping terms are not included, but it does not appear when damping terms are included.