FFT of sine wave

We typically diagram these as vertical lines in a graph where the horizontal position represents the frequency of the simple wave and its height represents the amplitude : This kind of spectrum diagram is especially convenient for naturally occurring waves, which are typically composed of a lot of simple waves.

The phase spectrum specifies the phase of signal components as a function of . component frequency . This phase is measured with respect to a cosine reference.

Frequency spectrum of a signal is the range of frequencies contained by a signal . For example, a square wave is shown in Fig. 3.5A. It can be represented by a series of sine waves, S(t) = 4A/π sin(2πft) + 4A/3π sin(2π(3f)t) + 4A/5π sin(2π(5f)t + …)

The signal spectrum describes a signal’s magnitude and phase characteristics as a function of frequency . The system spectrum describes how the system changes signal magnitude and phase as a function of frequency.