Principles of Operation
PRINCIPLES OF OPERATIONAudio Unit
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. When on, the audio unit directs audio signals to the speakers through separate positive and negative circuits for each of the audio channels. The audio unit provides internal circuit protection for shorts to ground, shorts to voltage, or shorts between any output circuits.
Noise Suppression Equipment
The radio interference suppression equipment reduces interference transmitted through the speakers by the engine ignition and electrical systems.
Antenna
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.
Subwoofers
The subwoofer speakers on the 500-watt system are located in the front doors and are powered by individual amplifiers located on each speaker. In addition to these subwoofer speakers, the 1000-watt system includes an enclosure with 2 subwoofer speakers powered by 2 amplifiers, each. The enable/clip circuit carries out 2 functions: to turn on the subwoofer amplifier, and to monitor an overload condition to the subwoofer amplifier. In the event of an overload, the audio unit clips the audio output signal to the subwoofer amplifier (heard as distortion).
Satellite Audio
The satellite audio system consists of a satellite radio receiver, a satellite radio antenna, and antenna cable (part of the decklid harness). 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 controller area network (CAN).
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.