Principles of Operation

PRINCIPLES OF OPERATION

Audio Unit
The audio unit can be powered up when the key is in RUN, ACC, or START. 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 and shorts to battery.

Antenna - AM/FM
The antenna is a fixed mast antenna mounted on the exterior of the vehicle. The antenna receives both AM and FM radio waves. The audio signals are then sent to the audio unit through the antenna cables.

Subwoofer
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 an excessive level. The audio unit then reduces (clips) the audio output signal to the subwoofer amplifier.

Digital Versatile Disc (DVD) Player
The DVD player receives power in RUN or ACC. The wake-up signal is sent to the DVD player from the audio unit through the medium speed controller area network (MS-CAN). When a video disc is inserted into the DVD player and PLAY is pressed, an image is displayed on the screen and a stereo signal is transmitted to the audio unit.

Satellite Audio
The satellite audio system consists of a satellite radio receiver, a satellite radio antenna, and an antenna cable. The satellite radio antenna receives digital audio signals and sends them to the satellite radio receiver, where the signals are converted and sent to the audio unit. The wake-up signal for the satellite radio receiver is sent from the audio unit through the MS-CAN.

Navigation
The navigation audio unit generates a display on a video screen. When an on-screen menu key is pressed, a new screen is displayed corresponding to the key that was pressed.

Audio Input Jack
The audio input jack allows for a portable MP3 player to be connected to the vehicle audio system. When a portable MP3 player is connected, audio from the MP3 player can be played through the vehicle speakers.

Steering Wheel Controls
The steering wheel controls consist of a series of resistors. Each steering wheel control switch function corresponds with a specific resistance value within the switch. When a switch is pressed, the audio unit monitors the change in reference voltage to determine the requested function.

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