Dolby Laboratories Inc, San Francisco, and Zoran Corp, Santa Clara, California, have announced the first results of their long-term technology alliance – a new programmable signal processor architecture and a family of integrated circuits designed for use in a variety of audio, speech and what they call performance-intensive applications. Zoran’s new ZR38000 signal processor is the initial milestone in the companies’ joint effort to migrate Dolby’s multi-channel digital film sound technology to home entertainment formats and for use in consumer products. The ZR38000 is claimed to be the only single-chip signal processor capable of encoding and decoding six-channel audio processed with Dolby’s AC-3 low bit-rate surround sound algorithm. It performs the same function as the five signal processors – Motorola Inc 56001s – originally required to decode AC-3 coded Dolby Stereo Digital film soundtracks. The first product to incorporate the ZR38000 will be Dolby Laboratories’ professional theatre decoders.
Audio buffs
Consumer products using the technology are expected to reach the market in 1994. The ZR38000 is a fixed-point digital signal processor architecture optimised for performance-intensive signal processing applications. It has 20-bit data precision to meet the needs of high quality audio processing, where the 16-bit precision common in most programmable signal processor architectures introduces unacceptable audible artifacts, the audio buffs will tell you. Its optimised 20-bit data path also enables the ZR38000 to be sold at lower cost than competing 24-bit fixed-point or 32-bit floating-point digital signal processors – but of course you get what you pay for. Its 32-bit wide instructions support an unprecedented degree of parallel execution, enabling it to process up to eight operations simultaneously. In addition, the ZR38000’s performance is boosted by the incorporation of a seven-port general-purpose data register file, dual extended-precision accumulator registers, a bi-directional barrel shifter, support for zero-overhead nested loops and an instruction cache. Unlike other fixed-point processors, the ZR38000 provides a 1M-word address space, making it useful in audio and image processing applications that store and process large amounts of data.
Fast Fourier
Operating at 25 MIPS, the ZR38000 computes a 1,024-point Radix-2 Complex Fast Fourier Transform in 0.87mS, making it the first fixed-point programmable digital signal processor to break the 1mS barrier. As well as announcing the new architecture, Zoran announced the first five members of the new family. The company will offer both user-programmable signal processors for use in performance-intensive, cost-sensitive applications, and application specific standard products based on the ZR38000 processor core optimised for targeted applications. The first two user-programmable ZR38000 family parts processors to be offered are the ZR38000 and the ZR38001. The ZR38000 incorporates 8K-words of on-chip program/coefficient Read Only Memory and 2K-words of on-chip RAM for data storage. It is optimised for applications requiring the use of relatively large off-chip program or data memories or for applications where the customer’s programs can be incorporated into the ZR38000’s on-chip ROM. In contrast, the ZR38001 offers a 1K-word on-chip program RAM, 2K-words on-chip data RAM, and a 1.5K-word ROM for coefficient storage. Minimal ZR38001 systems require no external memory, other than a single Erasable Programmable Read Only Memory chip for program and data storage, enabling the ZR38000 to be the basis for extremely low cost systems. Zoran also announced three application specific standard products based on the ZR38000 processor core, which are optimised for high quality audio processing and are targeted for use in cost-sensitive consumer and computer system applications. The ZR38500 provides full six-channel AC-3 decoding for home theatre products. To ensure compatibility with analogue Dolby Surround software, it will also be capable of Dolby Pro Logic decoding,
Zoran says.
Pro Logic
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The ZR38501 is optimised for two-channel Dolby AC-3 applications such as cable television and computer multimedia. Also, it can be capable of Pro Logic decoding. Both chips will be available in the second quarter of 1994. Finally, the ZR38511 is an application-specific standard product optimised for two-channel Motion Picture Experts Group audio decoding and targeted for use in computer multimedia and CD-ROM-based applications. Zoran also has development software that facilitates the development of ZR38000 assembly code. The ZR38000 Assembler, Linker and Simulator provide the programmer with an extensive environment for the development and debugging of algorithms written in the ZR38000’s native assembly language. The ZR38000 Development Software and simulator are available for Microsoft Corp Windows 3.1; the ZR38000 simulator provides a graphical user interface to facilitate information display and to ease code development. The ZR38000 is available now in a 128-pin plastic package at $42 in quantities of 1,000. High volume pricing for the ZR38000 is less than $25. The ZR38001, ZR38500, ZR38501, and ZR38511 will be available in the second quarter of 1994. The ZR38000 Development Software is available now for $500.
