It is very important that X-ray tube voltage and waveforms are accurately measured and evaluated. For estimation of the tube voltage waveforms, the tube voltage ripple and tube voltage peak number have been used. However, these are insufficient for more detailed estimation of the tube voltage wave forms. We suggest a frequency analysis method as a newer and more detailed one. In this method, waveforms are analyzed by using fast Fourier transform (FFT). In this paper, tube voltage waveforms in single-phase, three-phase, and constant potential generators will be estimated in detail. In single-phase and three-phase generators, our method is useful for the assessment of distortion of tube voltage waveforms. In a constant potential generator, it is convenient to carry out detailed evaluation of overshoot of tube voltage waveforms. In other words, this method makes possible an objective comparison and a careful examination of tube voltage waveforms in single-phase, three-phase and constant potential generators.
