DSPs

Vol. 2 No. 1 – March 2004

DSPs

Interviews

A Conversation with Teresa Meng

In 1999, Teresa Meng took a leave of absence from Stanford University and with colleagues from Stanford and the University of California, Berkeley, founded Atheros Communications to develop and deliver the core technology for wireless communication systems. Using a combination of signal processing and CMOS RF technology, Atheros came up with a pioneering 5 GHz wireless LAN chipset found in most 802.11a/b/g products, and continues to extend its market as wireless communications evolve.

A Conversation with Teresa Meng

In 1999, Teresa Meng took a leave of absence from Stanford University and with colleagues from Stanford and the University of California, Berkeley, founded Atheros Communications to develop and deliver the core technology for wireless communication systems. Using a combination of signal processing and CMOS RF technology, Atheros came up with a pioneering 5 GHz wireless LAN chipset found in most 802.11a/b/g products, and continues to extend its market as wireless communications evolve.

Articles

BPM: The Promise and the Challenge

Over the last decade, businesses and governments have been giving increasing attention to business processes - to their description, automation, and management. This interest grows out of the need to streamline business operations, consolidate organizations, and save costs, reflecting the fact that the process is the basic unit of business value within an organization.

BPM: The Promise and the Challenge
LAURY VERNER, PROACTIVITY

It’s all about closing the loop from conception to execution and back.

Over the last decade, businesses and governments have been giving increasing attention to business processes—to their description, automation, and management. This interest grows out of the need to streamline business operations, consolidate organizations, and save costs, reflecting the fact that the process is the basic unit of business value within an organization.

The design and automation of business processes even warrants its own field of study, known as BPM (business process management). A quote from IBM Systems Journal sums it up nicely: “BPM technology provides not only the tools and infrastructure to define, simulate, and analyze business process models, but also the tools to implement business processes in such a way that the execution of the resulting software artifacts can be managed from a business process perspective.”1

by Laury Verner

Of Processors and Processing

Digital signal processing is a stealth technology. It is the core enabling technology in everything from your cellphone to the Mars Rover. It goes much further than just enabling a one-time breakthrough product. It provides ever-increasing capability; compare the performance gains made by dial-up modems with the recent performance gains of DSL and cable modems. Remarkably, digital signal processing has become ubiquitous with little fanfare, and most of its users are not even aware of what it is. Therefore, it is worthwhile to look at the development history of DSP, an explanation of what the technology is, and a review of the many technologies that are used to implement modern digital signal processing systems.

DSP: Of Processors and Processing
GENE FRANTZ AND RAY SIMAR, TEXAS INSTRUMENTS

There’s more than one way to DSP.

Digital signal processing is a stealth technology. It is the core enabling technology in everything from your cellphone to the Mars Rover. It goes much further than just enabling a one-time breakthrough product. It provides ever-increasing capability; compare the performance gains made by dial-up modems with the recent performance gains of DSL and cable modems. Remarkably, digital signal processing has become ubiquitous with little fanfare, and most of its users are not even aware of what it is. Therefore, it is worthwhile to look at the development history of DSP, an explanation of what the technology is, and a review of the many technologies that are used to implement modern digital signal processing systems.

HISTORY AND APPLICATIONS

Digital signal processing is a wonderful blend of the theoretical and the practical. It is this blend that helps to explain much of its historical development. In the broadest sense, digital signal processing is the transformation of signals that have a digital representation. Today that has come to mean a large number of diverse processing tasks, as varied as voice compression, image recognition, and robotic control systems.

by Gene Frantz, Ray Simar

DSPs: Back to the Future

From the dawn of the DSP (digital signal processor), an old quote still echoes: "Oh, no! We'll have to use state-of-the-art 5µm NMOS!" The speaker's name is lost in the fog of history, as are many things from the ancient days of 5µm chip design. This quote refers to the first Bell Labs DSP whose mask set in fact underwent a 10 percent linear lithographic shrink to 4.5µm NMOS (N-channel metal oxide semiconductor) channel length and taped out in late 1979 with an aggressive full-custom circuit design. The designer I quoted had realized that the best technology of the time would be required to meet the performance demands of the then cutting-edge digital Touch-Tone receiver.

DSPs: Back to the Future
W. PATRICK HAYS, ULTRA DATA CORPORATION

To understand where DSPs are headed, we must look at where they’ve come from.

From the dawn of the DSP (digital signal processor), an old quote still echoes: “Oh, no! We’ll have to use state-of-the-art 5µm NMOS!” The speaker’s name is lost in the fog of history, as are many things from the ancient days of 5µm chip design. This quote refers to the first Bell Labs DSP whose mask set in fact underwent a 10 percent linear lithographic shrink to 4.5µm NMOS (N-channel metal oxide semiconductor) channel length and taped out in late 1979 with an aggressive full-custom circuit design. The designer I quoted had realized that the best technology of the time would be required to meet the performance demands of the then cutting-edge digital Touch-Tone receiver.

A parallel project at Intel would result in the Intel 2920 announced 25 years ago at ISSCC79 (International Solid-State Circuits Conference 1979).1 The Intel 2920 included on-chip (D/A) digital/analog and A/D (analog/digital) converters but lacked a hardware multiplier and soon faded from the market. An NEC project resulted in the NEC µPD7720—one of the most successful DSPs of all time. The Bell Labs DSP-1 and NEC µPD7720 were announced at ISSCC80.2 DSP-1 achieved 5-MHz clock speed, executing 1.25-MB multiply-accumulates per second at four clock cycles each—enough to allow Touch-Tone receiver filters to execute in realtime.

by W. Patrick Hays

Curmudgeon

Damnéd Digits

I remind you, first, that "damnéd" has two syllables, calling for a Shakespearean sneer as sneered by Olivier strutting his King Richard III stuff.

Damnéd Digits
Stan Kelly-Bootle, Author

I remind you, first, that “damnéd” has two syllables, calling for a Shakespearean sneer as sneered by Olivier strutting his King Richard III stuff.

by Stan Kelly-Bootle

Articles

Death by UML Fever

A potentially deadly illness, clinically referred to as UML (Unified Modeling Language) fever, is plaguing many software-engineering efforts today. This fever has many different strains that vary in levels of lethality and contagion. A number of these strains are symptomatically related, however. Rigorous laboratory analysis has revealed that each is unique in origin and makeup. A particularly insidious characteristic of UML fever, common to most of its assorted strains, is the difficulty individuals and organizations have in self-diagnosing the affliction. A consequence is that many cases of the fever go untreated and often evolve into more complex and lethal strains.

Death by UML Fever
ALEX E. BELL, THE BOEING COMPANY

Self-diagnosis and early treatment are crucial in the fight against UML Fever.

A potentially deadly illness, clinically referred to as UML (Unified Modeling Language) fever, is plaguing many software-engineering efforts today. This fever has many different strains that vary in levels of lethality and contagion. A number of these strains are symptomatically related, however. Rigorous laboratory analysis has revealed that each is unique in origin and makeup. A particularly insidious characteristic of UML fever, common to most of its assorted strains, is the difficulty individuals and organizations have in self-diagnosing the affliction. A consequence is that many cases of the fever go untreated and often evolve into more complex and lethal strains.

Little has been published in medical annals on UML fever because it has only recently emerged as an affliction. The New England Journal of Medicine has been silent on the disease, as has research produced by the world’s most prestigious medical institutions. The content of this article represents many years of on-the-job research and characterizes all known strains of UML fever, as well as many of the known relationships recognized to exist between them. The article will conclude with disclosure of the only known antidote for the many and varied strains of UML fever.

by Alex E. Bell

Digitally Assisted Analog Integrated Circuits

In past decades, "Moore's law" has governed the revolution in microelectronics. Through continuous advancements in device and fabrication technology, the industry has maintained exponential progress rates in transistor miniaturization and integration density. As a result, microchips have become cheaper, faster, more complex, and more power efficient.

Digitally Assisted Analog Integrated Circuits
BORIS MURMANN, STANFORD UNIVERSITY
BERNHARD BOSER, UC BERKELEY

Closing the gap between analog and digital

In past decades, “Moore’s law”1 has governed the revolution in microelectronics. Through continuous advancements in device and fabrication technology, the industry has maintained exponential progress rates in transistor miniaturization and integration density. As a result, microchips have become cheaper, faster, more complex, and more power efficient.

We will show, however, that digital performance metrics have grown significantly faster than corresponding measures for analog circuits, especially ADCs (analog-to-digital converters). Since most DSP (digital signal processor) projects depend on A/D conversion in the interfaces, this growing disparity in relative performance increase has the potential to threaten the rate of progress of DSP hardware.

by Boris Murmann, Bernhard Boser

On Mapping Alogrithms to DSP Architectures

Our complex world is characterized by representation, transmission, and storage of information - and information is mostly processed in digital form. With the advent of DSPs (digital signal processors), engineers are able to implement complex algorithms with relative ease. Today we find DSPs all around us - in cars, digital cameras, MP3 and DVD players, modems, and so forth. Their widespread use and deployment in complex systems has triggered a revolution in DSP architectures, which in turn has enabled engineers to implement algorithms of ever-increasing complexity. A DSP programmer today must be proficient in not only digital signal processing but also computer architecture and software engineering.

Mapping Algorithms to Architectures
HOMAYOUN SHAHRI, TUFON CONSULTING

Knowledge of both the algorithm and target architecture is crucial.

Our complex world is characterized by representation, transmission, and storage of information—and information is mostly processed in digital form. With the advent of DSPs (digital signal processors), engineers are able to implement complex algorithms with relative ease. Today we find DSPs all around us—in cars, digital cameras, MP3 and DVD players, modems, and so forth. Their widespread use and deployment in complex systems has triggered a revolution in DSP architectures, which in turn has enabled engineers to implement algorithms of ever-increasing complexity. A DSP programmer today must be proficient in not only digital signal processing but also computer architecture and software engineering.

This article focuses on mapping DSP algorithms to DSP architectures. The goal is to describe efficient methodologies and techniques to do so and to aid our readers in their work as DSP programmers. We discuss the types of algorithms that map well to DSPs and those that don’t easily map to DSP architectures, as well as the state of available tools that can facilitate simulation and mapping of algorithms to DSPs. We start by giving a short history and evolution of DSPs, then introduce DSP algorithms, look at DSP tools. We then describe efficient methodologies for mapping complex algorithms to DSP architectures, and to make our proposed methodology precise, we conclude with an example in which we map a well-known algorithm to a hypothetical architecture.

by Homayoun Shahri

Stream Processors: Progammability and Efficiency

Many signal processing applications require both efficiency and programmability. Baseband signal processing in 3G cellular base stations, for example, requires hundreds of GOPS (giga, or billions, of operations per second) with a power budget of a few watts, an efficiency of about 100 GOPS/W (GOPS per watt), or 10 pJ/op (picoJoules per operation). At the same time programmability is needed to follow evolving standards, to support multiple air interfaces, and to dynamically provision processing resources over different air interfaces. Digital television, surveillance video processing, automated optical inspection, and mobile cameras, camcorders, and 3G cellular handsets have similar needs.

Stream Processors: Programmability with Efficiency
WILLIAM J. DALLY, UJVAL J. KAPASI, BRUCEK KHAILANY, JUNG HO AHN, AND ABHISHEK DAS, STANFORD UNIVERSITY

Will this new kid on the block muscle out ASIC and DSP?

Many signal processing applications require both efficiency and programmability. Baseband signal processing in 3G cellular base stations, for example, requires hundreds of GOPS (giga, or billions, of operations per second) with a power budget of a few watts, an efficiency of about 100 GOPS/W (GOPS per watt), or 10 pJ/op (picoJoules per operation). At the same time programmability is needed to follow evolving standards, to support multiple air interfaces, and to dynamically provision processing resources over different air interfaces. Digital television, surveillance video processing, automated optical inspection, and mobile cameras, camcorders, and 3G cellular handsets have similar needs.

Conventional signal processing solutions can provide high efficiency or programmability, but are unable to provide both at the same time. In applications that demand efficiency, a hardwired application-specific processor—ASIC (application-specific integrated circuit) or ASSP (application-specific standard part)—has an efficiency of 50 to 500 GOPS/W, but offers little if any flexibility. At the other extreme, microprocessors and DSPs (digital signal processors) are completely programmable but have efficiencies of less than 10 GOPS/W. DSP (digital signal processor) arrays and FPGAs (field-programmable gate arrays) offer higher performance than individual DSPs, but have roughly the same efficiency. Moreover, these solutions are difficult to program—requiring parallelization, partitioning, and, for FPGAs, hardware design.

by William J. Dally, Ujval J. Kapasi, Brucek Khailany, Jung Ho Ahn, Abhishek Das