Howtosignalprocessing
What does a Bode plot tell you?
Bode plots show the frequency response, that is, the changes in magnitude and phase as a function of frequency. This is done on two semi-log scale plots. The top plot is typically magnitude or “gain” in dB. The bottom plot is phase, most commonly in degrees.
How does a Bode plot show stability?
If both the gain margin GM and the phase margin PM are positive, then the control system is stable. If both the gain margin GM and the phase margin PM are equal to zero, then the control system is marginally stable. If the gain margin GM and / or the phase margin PM are/is negative, then the control system is unstable.
