Principles of Operation

PRINCIPLES OF OPERATION

NOTE: The audio unit is also referred to as the audio control module.

The audio unit can be powered up when the ignition is in the ON or ACC position. The audio unit provides audio signals to the speakers, thus producing sound.

The audio unit directs the audio signals to the speakers through separate positive and negative circuits for each of the 4 audio channels: LH front, RH front, LH rear, and RH rear. The audio unit provides internal circuit protection for shorts to ground, shorts to B+ battery or shorts between any output circuits.

The subwoofer speaker is powered from a separate subwoofer amplifier. The enable/clip circuit carries out 2 functions: to turn the subwoofer amplifier on, and to indicate to the audio unit when the subwoofer output distortion signal reaches a damaging level. The audio unit then reduces the audio output signal to the subwoofer amplifier.

The digital versatile disc (DVD) player receives a wake up signal from the audio unit through the controller area network (CAN). When a video disc is inserted into the DVD player and the PLAY button is pressed, an image is displayed on the screen and a stereo signal is transmitted to the audio unit.

The radio suppression equipment reduces interference transmitted through the speakers by the engine ignition and electrical systems.

The steering wheel controls consists of a specific resistor value for each button function creating a voltage divider. When a button is pressed, a specific reference voltage is sent to the audio unit. The audio unit then uses this reference voltage to determine which control input function has been selected.