
The Bode magnitude plot is the graph of the function | H ( s = j ω ) | |H(s=j\omega )| of frequency ω \omega (with j j being the imaginary unit). The Bode plot for a linear, time-invariant system with transfer function H ( s ) H(s) ( s s being the complex frequency in the Laplace domain) consists of a magnitude plot and a phase plot. The Bode plot is an example of analysis in the frequency domain. The principles developed were applied to design problems of servomechanisms and other feedback control systems. He developed the graphical design technique of the Bode plots to show the gain margin and phase margin required to maintain stability under variations in circuit characteristics caused during manufacture or during operation. īode was faced with the problem of designing stable amplifiers with feedback for use in telephone networks. "Bode" is often pronounced / ˈ b oʊ d i/ BOH-dee although the Dutch pronunciation is Bo-duh. These bear his name, Bode gain plot and Bode phase plot. Overview Īmong his several important contributions to circuit theory and control theory, engineer Hendrik Wade Bode, while working at Bell Labs in the 1930s, devised a simple but accurate method for graphing gain and phase-shift plots. It is usually a combination of a Bode magnitude plot, expressing the magnitude (usually in decibels) of the frequency response, and a Bode phase plot, expressing the phase shift.Īs originally conceived by Hendrik Wade Bode in the 1930s, the plot is an asymptotic approximation of the frequency response, using straight line segments. In electrical engineering and control theory, a Bode plot / ˈ b oʊ d i/ is a graph of the frequency response of a system. Figure 1B: The Bode plot for a first-order (one-pole) lowpass filter the straight-line approximations are labeled "Bode pole" phase is 90° lower than for Figure 1A because the phase contribution of the numerator is 0° at all frequencies. JSTOR ( December 2011) ( Learn how and when to remove this template message)įigure 1A: The Bode plot for a first-order (one-pole) highpass filter the straight-line approximations are labeled "Bode pole" phase varies from 90° at low frequencies (due to the contribution of the numerator, which is 90° at all frequencies) to 0° at high frequencies (where the phase contribution of the denominator is −90° and cancels the contribution of the numerator).Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.
