Bode diagrams or logarithmic plots. A sinusoidal transfer function may be
represented by two separate plots, one giving the magnitude versus frequency and the
other the phase angle (in degrees) versus frequency. A Bode diagram consists of two
graphs: One is a plot of the logarithm of the magnitude of a sinusoidal transfer func-
tion; the other is a plot of the phase angle; both are plotted against the frequency in
logarithmic scale.
The standard representation of the logarithmic magnitude of G(jw) is 20 log |G(jw)|,
where the base of the logarithm is 10. The unit used in this representation of the
magnitude is the decibel, usually abbreviated dB. In the logarithmic representation, the
curves are drawn on semilog paper, using the log scale for frequency and the linear scale