【正文】 附錄A英文文獻(xiàn)DSPs Back to the Future[13]W. Patrick HaysPublished online： 23 June 2004Springer Science + Business Media . 2004AbstractOur plex world is characterized by representation, transmission, and storage of informationand information is mostly processed in digital form. With the advent of DSPs (digital signal processors), engineers are able to implement plex algorithms with relative ease. Today we find DSPs all around usin cars, digital cameras, MP3 and DVD players, modems, and so forth. Their widespread use and deployment in plex systems has triggered a revolution in DSP architectures, which in turn has enabled engineers to implement algorithms of everincreasing plexity. A DSP programmer today must be proficient in not only digital signal processing but also puter architecture and software engineering.Keywords　 DSP；Motor control systemThe Intel 2920 included onchip (D/A) digital/analog and A/D (analog/digital) converters but lacked a hardware multiplier and soon faded from the NEC project resulted in the NEC 181。PD7720—one of the most successful DSPs of all Bell Labs DSP1 and NEC 181。PD7720 were announced at ,achieved 5MHz clock speed，executing multiplyaccumulates per second at four clock cycles each—enough to allow TouchTone receiver filters to execute in once formidable performance demands of the TouchTone receiver are now ludicrously easy, but new applications in turn arose throughout the last 20 years to put new demands on DSP technology (see figure 1).According to Will Strauss,president and principal analyst at Forward Concepts, “DSP shipments were up a healthy 24 percent in 2003, and we are forecasting a bit higher growth for 2004, at 25 percent. Longer term,we forecast a percent pound growth rate through 2007.”So the game has been: Boost DSP performance, run the algorithm atan acceptable cost, and open up a new mercial is perhaps too glib to project this trend indefinitely into the future,In fact, savvy analysts have periodically predicted the demise of the performance requirements outstripthe ability of programmable DSP architectures to keep up, thus demanding a new approach?or if DSPs are to maintain their historical growth curve，what kinds of tools and architectures are needed? Ultimately，these questions will be answered by creative architects，market petition， and application demands. The goal of this article is to illuminate current and future trends by reviewing how technology and application pressures have shaped DSP architecture in the past. WHAT IS A DSP？At the outset，it is important to distinguish between digital signal processing and digital signal processors. The techniques and applications of digital signal processing, as pared with analog signal processing，are well established and are more important mercially than ever. Throughout this article,DSP refers to the VLSI (very largescale integration) processor ponent. Therefore，what special demands in digital signal processing make a DSP different from another programmable processor？In other words,what makes a DSP a DSP?The Realtime Requirement. The essential application characteristic driving DSP architecture is the requirement to process realtime means that the signal represents physical or “real” events. DSPs are designed to process realtime signals and must therefore be able to process the samples at the rate they are generated and arrive. Adding significant delay,or latency,to the output can be objectionable. While high realtime rates often demand that DSPs be “fast” ,fast and realtime are different example，simulations of VLSI designs must be fast—the faster the better but the application doesn’t fail if the simulator pletes a little slower. Conversely，a realtime application need not be fast—for example,a hospital room heart monitor doesn’t need to be fast (30Hz sample rate) but does need to be realtime。 it would be disastrous if the processing of a sample took so long that after a few hours，the monitor was displaying fiveminuteold data. Not all digital signal processing applications require realtime applications are performed offline. For instance， encoding highfidelity audio for mastering CDROMs uses sophisticated digital signal processing algorithms， but the work isn’t done in ，a DSP isn’t required—any old processor fast enough for the engineer to get home for dinner will do. To summarize, the most important distinguishing characteristic of DSPs is that they process realtime signals—the signals can be fast or slow, but they must be . Do DSPs need to be programmable? No:it’s quite feasible to process digital signals without a programmable this article, however, DSP refers to programmable DSP—more specifically，to userprogrammable DSPs, because my bias is that that’s where the most interesting architectural issues lie. Often,the most demanding applications have required nonprogrammable architectures. For instance,firstgeneration programmable DSPs could execute a single channel of the 32Kbps ADPCM/DLQ,(adaptive differential pulse code mo