Abstract: An automobile head unit display system including an antenna, a lightbox assembly and a circuit board is described therein. The antenna is attached to the lightbox system, while the lightbox assembly is attached to the circuit board. The antenna and the lightbox assembly are in communication with the circuit board.

Abstract: An audio multimedia player has dual access modes for navigating between track selections contained in a large storage media, such as a compact disc CD-ROM having compressed audio files. The disc may includes numerous directories for organizing the audio files, but the player has insufficient display resources to show the directories themselves. In a flat file mode, all target audio file on the disc are included in a sequential numbering scheme which ignores any directory structure. In a directory mode, all directories are collapsed onto a single directory level in which subdirectories are moved up to the same top level as all other directories. The directories are sequentially numbered and then the target audio files within each directory are sequentially numbered.

Abstract: The presence or absence of a speaker connected to an output terminal of an audio system is determined based on the electro-generator properties of the speaker. The audio system includes an output amplifier coupled to the output terminal. The method includes driving the output amplifier with a predetermined drive signal sufficient to produce a predetermined speaker excursion if a speaker is connected to the output terminal. The output amplifier is then isolated from the output terminal. A signal at the output terminal is sensed after the output amplifier is isolated. The sensed signal is compared with a predetermined reference for determining whether a speaker back-EMF is present. A speaker detection signal is generated indicating absence of a speaker if the back-EMF is not present.

Abstract: A multimedia player having a limited user interface achieves quick and easy navigation within a large playlist of stored digital audio files by employing the rotary volume control knob in a separate mode to advance or rollback sequentially through the playlist. Thus, an MP3 player can be implemented for an automotive or vehicular multimedia player without increasing the number of user control elements, such as buttons, knobs, or other switches.

Abstract: The presence or absence of a speaker connected to an output terminal of an audio system is determined based on the electro-generator properties of the speaker. The audio system includes an output amplifier coupled to the output terminal. The method includes driving the output amplifier with a predetermined drive signal sufficient to produce a predetermined speaker excursion if a speaker is connected to the output terminal. The output amplifier is then isolated from the output terminal. A signal at the output terminal is sensed after the output amplifier is isolated. The sensed signal is compared with a predetermined reference for determining whether a speaker back-EMF is present. A speaker detection signal is generated indicating absence of a speaker if the back-EMF is not present.

Abstract: A method of detecting a DC offset in an audio signal provided by an audio processing unit to an audio power amplifier, wherein the audio amplifier provides a clip detect signal back to the audio processing unit, wherein the method comprises the steps of sampling the clip detect signal to determine if the clip detect is active. Detecting a power level of the audio amplifier if the clip detect is active. Next, comparing the power level to a predetermined power threshold. Then, identifying a dc offset if the power level is less than the predetermined power threshold.

Abstract: A digital signal processing automotive audio system uses an analog audio source providing stereo output signals. One of the stereo signals is mixed to a distinct frequency band and summed with the other stereo signal to form a composite signal which can be digitized in a single analog-to-digital converter. Separate digital stereo signals are recovered using digital signal processing.

Abstract: A power device assembly comprises a circuit board sub-assembly and a protective housing enclosing the circuit board sub-assembly. The circuit board sub-assembly includes a heat sink frame around the periphery of a circuit board. Heat generating power devices and, optionally, other circuit devices are mounted in thermally conductive contact with the heat sink frame. Electrical leads extend from the power devices to the circuit board where a solder connection is formed. The heat sink frame extends outwardly beyond the circuit board, at least a portion extending outwardly from the protective housing to provide cooling means for the assembly. According to a method of the invention, a sub-assembly comprising the circuit board, heat sink frame and power device is assembled and the heat sink frame is used as a palette to support and carry the circuit board through a wave soldering process.

Abstract: An audio system having a main chassis including an audio preamplifier and a remote chassis including a power amplifier has a clipping level detector circuit in the remote chassis for detecting the onset of clipping by the power amplifier and has a gain control element in the main chassis for controlling the gain of the preamplifier. An extra control line in the wiring harness connecting the main chassis and the remote chassis is avoided by multiplexing the clipping signal and the mute control signal on a single control wire.