Bodekuviot

Bodekuviot are graphical representations of a system’s response to different frequencies. They show how the complex transfer function H(jω) behaves as frequency ω varies. A Bode diagram typically consists of two plots on a common frequency axis: the magnitude plot, which shows |H(jω)| in decibels (dB), and the phase plot, which shows the phase angle ∠H(jω) in degrees. The frequency axis is on a logarithmic scale, allowing a wide range of frequencies to be displayed compactly. In many cases the two plots are presented side by side as a combined Bode diagram.

The plots are named after Hendrik Wade Bode, who introduced the method at Bell Labs in the 1930s–1940s. They are widely used in electrical engineering, control theory, and signal processing for linear time-invariant systems, including filters and controllers.

Practitioners often use asymptotic straight-line approximations to quickly estimate behavior: each pole contributes a -20 dB/decade slope after its break frequency, each zero contributes +20 dB/decade, and phase shifts occur across break frequencies. The magnitude plot helps assess gain and bandwidth, while the phase plot informs phase margin and stability in feedback systems.