Technical introduction | Bode Plot principles The second important limit is the +3 dB line. If the gain response of the closed loop exceeds this limit, this is referred to as positive feedback, analogous to the field of audio engineering (a speaker with a microphone close to the loudspeaker) This positive feedback generates an undesired mechanical oscillation, which can lead to uncontrolled behavior. By increasing the P part (proportional gain), the curve is shifted upwards in parallel to the x-axis; a reduction has the opposite effect. TE132x 13 Version: 1.3.0