Terrain FWD L4-2.4L (2010)
Signal Processing Module: Description and Operation
Active Noise Cancellation Description and Operation
The entertainment system on this vehicle may have several different configurations. To determine the specific configuration of the vehicle, please see the
Service Parts ID Label, and refer to RPO Code List (See: Application and ID/RPO Code List).
Active Noise Cancellation (ANC) is a method used to cancel out undesirable sound generated by the engine or an open window.
Active Noise Cancellation Control Circuit Operation
An Active Noise Cancellation (ANC) system has four main components: the ANC module, microphone(s), audio amplifier(s), and speaker(s). The
microphone is connected to the audio system and picks up the sound/noise in the vehicle cabin while the speakers produce the cancellation vibrations.
The ANC system is composed of two microphones. The microphones are centrally located in the headliner to detect noise in the vehicle caused by the
engine, or an open window. The processor analyzes the noise signal and outputs a cancellation signal audio tone based on positive coefficient and phase
change to moderate the engine noise and make the vehicle seem quieter and without vibration. The ANC system uses the engine revolutions per minute
(RPM) signal from the tachometer to determine the rotational speed in an engine. The ANC system works within 1500-2500 engine RPM. The
cancellation signal is then amplified and a signal is sent to the speaker and subwoofer.
