1. Introduction

The Bode plots (in honor of H. W. Bode) constitute a convenient way to represent the frequency response characteristics of a system.

The amplitude ratio (AR) and the phase shift (\(\phi\)) of the ultimate response of a system are functions of the frequency \(\omega\).

Bode plots consist of a pair of the plots showing:

How the logarithm of the amplitude ratio varies with frequency.

How the phase shift varies with frequency.

In order to cover a large range of frequencies, we use logarithmic scale for frequencies.