Anything related to Bode plots, i.e. a special graphical representation of the frequency response of a linear time-invariant system.
Anything related to Bode plots, i.e. a special graphical representation of the frequency response of a linear time-invariant system, which is a complex-valued function of frequency describing how the systems reacts to sinusoidal signals of different frequency.
The frequency response \$H(f)\$ of a system is related to (and sometimes mistakenly confused with) its transfer function \$G(s)\$ by the formula:
$$ H(f) = G(j 2 \pi f) $$
Bode plots are the plots of the amplitude (in decibels) and phase components of the complex-valued function \$H(f)\$ versus frequency (this latter in logarithmic units), i.e.:
The plots of $$ 20\;log_{10}|H(f)| $$ and $$ arg(H(f)) $$ versus logarithmic frequency are the Bode magnitude plot and the Bode phase plot respectively.
See also Wikipedia on Bode plots.
