Digital audio mixer: A VLSI approach

Audio mixing panels have traditionally been implemented using analog circuits. The limitations of analog circuits, noise and flexibility, have been outweighed by the the power requirements and complexity of digital alternatives. The power consumption of digital processing circuits can be reduced by the use of VLSI circuits. The primary remaining limitation, circuit complexity, is minimized by using a simple self-framing serial data format for transmission of signals. Control circuitry is minimized by using the same serial data format for transmission of packetized control data. An attractive digital VLSI architecture for an audio mixing panel is proposed. The proposed digital interface standard is not limited to audio mixers; use of this interface standard will allow other speech or audio signal processing chips to be easily integrated into a system. A VLSI chip was built to prove the viability of the digital audio system concept. The chip accepts two streams of digitized audio samples, and selectively delays one stream to provide word synchronization with the other. The chip may be used in audio mixers and signal processors, or may be adapted as a subcomponent of larger chips.