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Audio post-processor ICs for DTV deliver home-theatre features

Austin, Tex.&#8212Cirrus Logic's CS48520 and
CS48540 for digital TV (DTV) applications are complete audio post-processing solutions designed to deliver home-theater-like audio quality.

“Consumers are enjoying the display features of new flat-panel TVs, but they are less satisfied with the audio capabilities of these products,” said Keith Cheney, vice
president and general manger of Embedded Products. “Manufacturers of DTV products that provide a better audio experience to their customers will
enable their products to stand out from the crowd.”

The CS48520 provides four channels of in/out audio and is ideally designed for two or 2.1-channel stereo
applications, whereas the CS48540 provides eight channels of in/out audio and is targeted for multichannel systems. Audio algorithms are supported within ROM, eliminating the need for external memory. The company also provides a PC-based graphical programming tool that allows system designers to quickly and easily set the audio's performance specifications.

Thus OEM designers can implement “surround sound.” The CS48520 and CS48540 include support for a wide variety of industry standard audio algorithms to expand stereo audio or matrix encoded stereo audio to multichannel audio and convert multichannel audio to stereo audio while preserving the “surround sound” effect. Other standard audio algorithms produce expanded, spatially separated stereo
audio, increase dialog clarity, and provide bass enhancement. Algorithm support includes Audistry by Dolby, Dolby ProLogic II, Dolby ProLogic IIx, Dolby
Virtual Speaker II, Dolby Headphone II, DTS Neo:6, SRS WOW HD(TM), SRS Circle Surround II, SRS TruSurround XT, SRS TruSurround HD, SRS TruBass, BBE, BBE Viva2, BBE Viva+, BBE Mach3Bass and Cirrus Original Multichannel Surround.

The chips also facilitate dynamic volume leveling. This audio feature allows TV viewers to predetermine their preferred audio volume listening level, and automatically
adjusts the volume for overly-loud commercials or for audio volume discrepancies between stations when channel surfing, or when switching between such incoming sources as a DVD player or set top box.

The chips also incorporate other enhanced listening modes such as movie, news, sports, music, and night modes. For example, news mode adjusts the audio for improved voice clarity during dialog intensive programs, while night mode limits extremely high-volume audio passages and reduces bass output, such as during action sequences in movie soundtracks. The bass management feature allows OEMs to more effectively manage the audio provided to the TV main speakers, with often limited low-frequency capabilities, by routing the low-frequency audio to an external sub-woofer for faithful reproduction of the bass content. The chips also provide speaker and cabinet tuning to optimize the audio performance of the DTV system by adjusting the many elements of audio response for the particular speaker and cabinet configuration in use. Automatic room equalization is provided, which calibrates the audio frequency response from the TV's speakers to improve the sound quality within the listening area, thus adjusting for room acoustics that can alter the overall sound quality (such as hardwood floors, mirrors, drapes, furniture, etc.) An A/V sync delay feature is also provided to provide up to 200 ms of audio delay to allow the audio to be properly synchronized with the video (which is delayed as a result of the video processing which occurs in the DTV system).

Click here to access the CS48500 product family datasheet. The CS48520 is priced at $2.08 each in one million volume, and the CS48540 is $2.49.

Cirrus Logic , 1-800-888-5016, www.cirrus.com

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