The Imaginary Part: A Source of Creativity in Instrumentation and Measurement

To analyze a signal digitally in instrumentation and measurement, we need to record a series of samples of that signal, which we refer to as a captured waveform. The author discusses the discrete Fourier transform (DFT) which is a widely used powerful signal analysis method. The discrete nature of the method implies that the captured waveform being analyzed is a portion of a periodic signal, and the transform is performed on a whole period or an integer multiple of periods