Digital Signal Processor

Tom Thompson   Today’s Top Stories   or  Other Software Stories  

Gain a faster, cheaper way to manage workload Migrating to Vista Sea Change Investment Fund Talks About Google Apps Ensuring SOA success with effective, automated control throughout the lifecycle Building the Bridge to SOA BPM Done Right: 15 ways to succeed where others have failed Virtual Reality SaaS Solutions for Remote Systems Management Mobility @ the Speed of Business Sign up to receive Desktop Applications Resource Alerts

March 12, 2001 (Computerworld) -- Every modern computer has a microprocessor in it, but not many have a digital signal processor (DSP). Since the CPU is a digital device, it clearly processes digital data, so you might wonder what the difference is between digital data and a digital signal. Basically, signal refers to communications—that is, a continuous stream of digital data that might not be stored (and thus might not be available in the future) and that must be processed in real time.

The digital signals can come from almost anywhere. For example, downloadable MP3 files store digital signals that represent music. Some camcorders digitize the video signals they generate and record them in a digital format. And the more sophisticated cordless and cellular phones typically convert your conversation into a digital signal before broadcasting it.

Variations on a Theme

A DSP differs markedly from the microprocessor that serves as the CPU in a desktop computer. A CPU's job requires it to be a generalist. It has to orchestrate the operation of diverse pieces of computer hardware, such as the hard disk drive, the graphics display and the network interface, so they work together to perform useful tasks.

This agility means that a desktop microprocessor is complex—it must support key features such as memory protection, integer arithmetic, floating-point arithmetic and vector/graphics processing.

As a result, a typical modern CPU has several hundred instructions in its repertoire to support all of these functions. This requires that it have a complex instruction-decode unit to implement the large instruction vocabulary, plus many internal logic modules (termed execution units) that carry out the intent of these instructions. As a result, a typical desktop microprocessor contains tens of millions of transistors.

In contrast, a DSP is built to be a specialist. Its sole purpose is to modify the numbers in a digital signal stream—and do it quickly. A DSP's circuits consist mainly of high-speed arithmetic and bit-manipulation hardware that can rapidly modify large amounts of data.

As a consequence, its instruction set is much smaller than that of a desktop microprocessor—perhaps no more than 80 instructions. This means that the DSP needs only a slimmed-down instruction-decode unit and fewer internal execution units. Moreover, any execution units that are present are geared toward high-performance arithmetic operations. Thus, a typical DSP consists of only several hundred thousand transistors.

As a specialist, a DSP is very good at what it does. Its myopic focus on math means that a DSP can continuously accept and modify a digital signal, such as an MP3 music recording or a cell phone conversation, without stalling or losing data. To help improve throughput, DSPs have extra internal data buses that help shuttle data among the arithmetic units and chip interfaces faster.

Continued...
1 | 2 | NEXT  

Print this Story

Send Us Feedback

E-mail this Story

Digg this Story

Slashdot this Story

"This IT pilot fish is working on top of a raised platform running network cable when his employer-supplied cell phone..." Read more... "In Tuesday's IT Blogwatch, we watch IBM launch social-networking-in-the-cloud/software-as-a-service tools for business-unified-messaging-and-collaboration (phew). Not to mention the video-game election......" Read more... Read more Software posts or See all Blogs

Update: AMD spins off manufacturing to cut costs, raise funds IBM launches Bluehouse, a Facebook for business iPhone grabs top smart phone spot More top stories...

Microsoft's (un)secret weapon for winning the BI battle Microsoft scales out SQL Server 2008, wants to 'democratize BI' Oracle tries to step up on high-end databases

Health hazards for IT workers -- how that desk job wears your body down Too much junk food, too little exercise and a 24/7 tether to technology? Your body ain't happy, friend. Let us count the pains. NASA robot sends back evidence it's snowing on Mars Instruments on the surface of Mars have detected falling snow that is likely evaporating before it reaches the planet. Wall Street's collapse may be computer science's gain One positive development stemming from the collapse of Wall Street may be a boost in interest in computer science and IT careers among students who were previously interested in financial services jobs. Installing Linux apps: A few good tips Getting new software installed on Linux doesn't have to be hard, but it can differ depending on what you're installing. Windows Vista A to Z Reviews, analyses, how-tos, visual tours, hot issues and predictions about Microsoft's new OS. More Continuing Coverage After 9/11: Homeland Security Apple's iPhone Ask a Premier 100 IT Leader Bill Gates steps down BlackBerry Legal Battle Data Security Breaches Electronic Voting Firefox H-1B Visas HP's Boardroom Scandal Handheld Devices Hurricane Katrina Aftermath Microsoft Legal Issues Microsoft's Vista Open Source RFID Technology SCO's Linux Fight Sarbanes-Oxley Act Spam Voice Over IP Wi-Fi Windows Meta File Vulnerability Windows XP Service Pack 3 IT Careers 2010 Four years from now, the IT field will be a vastly different place. Will you be ready? More Special Reports Premier 100 IT Leaders 2007 Best in Class 2006 Computerworld Horizon Awards 2006 Premier 100 IT Leaders 2006 Salary Survey 2007 Best Places to Work in IT 2007 IT Forecast 2007 Premier 100 IT Leaders 40 Years of Computerworld ASPs, Take Two Best Places to Work in IT 2003 Best Places to Work in IT 2004 Best Places to Work in IT 2005 Best Places to Work in IT 2006 Business Intelligence Home Runs Business Intelligence: Smarter BI Business Intelligence: The Future of BI CRM Goes Vertical CRM: Sober CRM Career Planning Guide 2005 Careers: IT Profession 2010 Computerworld Horizon Awards 2005 Data Management: Mining for Gems Data Management: Taming Data Chaos Development: Hard-Workin' Web Sites Development: New Tools New Choices Development: The New World of Application Development Development: The Web Services Tsunami Development: Web Services Hurdles Disaster Recovery: Preparing for the Worst E-commerce Grows Up E-mail/Groupware: Big Decisions Faces of Mobile IT Forecast 2006 Global Mobile Hardware: Multiple Cores, Multiple Challenges Hardware: On-Demand Un-Hyped Hardware: The Shape of Things to Come Horizon Awards: 10 Cool Cutting Edge Technologies IT Management: Guide to Managing Vendors IT Management: Navigating Global IT IT Management: Recovery Ahead IT Management: The Future of IT IT Management: The Resourceful Project Manager Innovative Technology Awards 2004 Management: Reinventing IT Microsoft in Transition Mobile/Wireless Leaders and Laggards Mobile/Wireless: The Untethered Worker Mobile/Wireless: Tiny Gadgets, Huge Costs Network Management: Taking Control Networking: Turbulence Ahead! Networking: VoIP Goes Mainstream Operating Systems: In the Slow Lane Operating Systems: Linux Goes Global Operating Systems: Should You Nix Unix? Outsourcing: Offshore Buyer's Guide Outsourcing: Outsourcing Dangers Premier 100 IT Leaders 2004 Best in Class Premier 100 IT Leaders 2005 Best in Class ROI: Do the Math! Salary Survey 2003 Salary Survey 2004 Salary Survey 2005 Security Action Plan Security: Compliance Headaches Security: Proactive Security Security: Risk and Reward Security: Tips From Security Pros Souped-up Security Storage: Battling Complexity Storage: Cheap & Secure Data Stores Storage: Stretching Your Storage Dollars Storage: The Lean Storage Machine Storage: The New Rules of Storage Storage: The Ultimate Backup Guide Supply Chain: Missing Links Supply Chain: RFID Reality Check The Business of Security Web 2.0 Security Wireless: Wireless At Work All Zones Application Performance Zone Business Continuity Zone The File Data Management Zone Security Management Zone The SAS Zone Business Intelligence and Analytics Zone Windows Protection Zone The Enterprise Search Zone Software as a Service Zone See your link here

Learn-Fast Guide: Software as a Service is Growing Up Download this Computerworld Executive Briefing, a $195 value, for free! Compliments of Akamai. (Source: Computerworld) SaaS is here to stay as an application delivery channel. You will be using it, but will you do so wisely? This Learn-Fast Guide will prepare you for software delivered over the Web. From security issues to contract negotiations, there's a lot to consider ... and a lot to gain. Download this executive briefing  From Laggard to Leader: Transforming the Data Center From Laggard to Leader: Transforming the Data Center Register for this complimentary webcast today! Go to the webcast  Grappling with Application Management Get this white paper now! (Source: Dell) Managing applications is a big business challenge today. When applications must be updated, installed or migrated, companies must ensure disruptions are minimized to keep users productive throughout the process. Dell provides services that can help every step of the way. Download this white paper  White Papers Read up on the latest ideas and technologies from companies that sell hardware, software and services. The Guide to Troubleshooting Application Problems Putting the Right Model in Place to Better Balance IT Supply and Business Demand Six Project Metrics Every CIO Should Know for Application Delivery Success View more whitepapers

• Update: AMD spins off manufacturing to cut costs, raise funds
• Microsoft's (un)secret weapon for winning the BI battle
• IBM launches Bluehouse, a Facebook for business
• More top stories 

"Turning information into a Competitive Advantage" Companies today are realizing that competitive advantage is harder to sustain when based solely on gains in productivity and cost efficiency. The focus is shifting to invest more in business optimization initiatives which rely on trusted information to develop new insights that deliver better business results. But how can this be done efficiently in a business environment across multiple applications and processes. The answer is an Information Agenda - an innovative approach to transforming business information into a strategic asset for competitive advantage. View this webcast now!  See more Webcasts

Accelerate your pursuit of perfection For almost 80 years, Kodak has been helping banks, insurance companies, healthcare providers, government agencies and other businesses produce billions of document images. So Kodak is uniquely positioned to know and deliver–what customers want: easy-to-use scanners that output the best possible image quality. Download this white paper now!

This podcast delivers summaries of key technologies and concepts every week. Listen to the short program on your iPod or in your Web browser. This Week: Darwin Information Typing Architecture,  List of Episodes Subscribe