Looking at the past year, a striking trend emerges: Increasingly, the hardware used for signal processing is something other than a DSP. I quickly surveyed the year's developments by skimming the archives on www.InsideDSP.com and discovered that only about half of the chips BDTI wrote about were DSPs. The rest were general-purpose processors, FPGAs or other hardware.

Ironically, DSPs are facing growing challenges partly because of the increasing importance of signal processing in a range of applications. Today, signal processing is found in everything from digital power supplies to portable video players. The prevalence of signal-processing workloads has motivated processor vendors of all stripes to add DSP-oriented features. For example, the latest ARM and MIPS architectures have remarkable similarities to DSP architectures.

Processor architecture is also less of a differentiator because processor vendors' solutions are more complex. Ten years ago, a typical solution consisted of a DSP and basic software tools. The main value was the power of the DSP architecture. Today, a typical solution consists of a highly integrated system-on-chip, sophisticated tools, operating systems and more. With such a solution, the processor architecture is often hidden from the user under layers of hardware and software.

Processor architecture is still important, but it has become only one of the factors that determine a solution's suitability.

Signal-processing applications are also increasingly complex. Ten years ago, signal-processing applications typically incorporated little nonsignal-processing functionality. For those applications, a DSP was often the only sensible choice. Today, an application with signal-processing workloads may also need to run Linux, handle 3-D graphics or perform packet processing. For apps with diverse workloads, it is reasonable to consider a diverse range of architectures-and a DSP won't always be the right solution.

For that matter, DSPs aren't always the right choice even for applications that are narrowly focused on signal processing. Other approaches sometimes offer lower prices or better performance. For example, FPGAs can beat DSPs in cost and performance in many communications-infrastructure applications.

Despite the challenges, however, DSPs are not about to go away. The fact that DSPs are purpose-built for signal-processing workloads ensures that DSPs will continue to have important advantages for some of those workloads. For example, DSPs have clear advantages for many audio applications because of their appealing mix of performance, programmability, integration and price.

For processor vendors, the message is clear: Customers don't care about fancy DSP architectures; they want solutions that solve their specific design problems. This means that processor vendors must clearly demonstrate how their solutions meet application needs.

And system designers must consider all relevant processors, regardless of what those processors are called. To do so, system designers must understand the strengths and weaknesses of many kinds of architectures. And they must look beyond architecture, evaluating factors such as the availability of off-the-shelf software. Only then can they choose a winner from among the many options.

Jeff Bier is president of Berkeley Design Technology Inc. (Berkeley, Calif.). BDTI colleague Kenton Williston contributed to this column.