Audio processor IC integrates karaoke voice canceller function

Designed for hi-fi systems and karaoke machines, SGS-THOMSON's TDA7430 digitally controlled audio processor combines bus controlled volume, tone and balance controls, a surround sound matrix and a voice cancelling function.

The voice cancelling function exploits the fact that on most sound recordings the main vocal is in the center of the stereo image. Matrix processing can therefore attenuate the voice leaving the backing track virtually unchanged. Thanks to this feature almost any disk or tape can be used for Karaoke.

Basic audio processor functions included on the chip are a four channel input selector, treble and bass tone controls, volume and left-right balance controls. Thanks to the use of mixed bipolar-CMOS technology noise is better than 30uVrms, the volume and tone steps are just 2dB and distortion is less than 0.01%.

Also integrated on the chip is a surround sound matrix which uses phase shifters to create three surround sound effects: "music" (a concert hall effect), "movie" (ideal for watching movies on TV) and "simulated stereo". These effects are selected by loading commands through a serial bus. By loading an internal eight bit control register the surround sound processor can be programmed to give 256 different arrangements of the movie effect.

The TDA7430 is available in QFP44 Quad Flat Pack surface mounting package or a narrow DIP SDIP42 insertion package. A version without the input selector switch - type TDA7431 - is also available.

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