Radio, Stereo, and Compact Disc: Description and Operation
AUDIO SYSTEMThe audio system and digital versatile disc (DVD) player are enabled when the ignition switch is in the ON or ACC position. The entertainment system is also powered during delayed accessory. The speakers are powered directly by the audio unit. All audio units (except the base model) have steering wheel controls. The antenna system contains an antenna amplifier module that helps reduce interference when using the AM/FM bands. When the audio unit is powered up, audio output signals are sent to the speakers as a fluctuating AC voltage, thus producing sound from the speakers.
The steering wheel controls are a multiplexed system that use different resistor values to produce different voltage levels on a single circuit. Each button that is pressed results in a unique voltage signal at the audio unit. This voltage signal is then interpreted by the audio unit as a distinct command. The audio unit also has a self-diagnostic mode that can be entered by pressing preset buttons 3 and 6 simultaneously.