Historically, DSP processors have been the default choice for signal processing applications because they could efficiently process classical signal processing functions like FIR filters and FFTs. But those capabilities aren’t enough any more. Signal processing applications still include demanding real-time filtering and frequency transforms, but these algorithms are increasingly combined with processing that is fundamentally different.

The DSP processor landscape is changing in many ways.  For example, in years past, vendors offered numerous “general-purpose” DSPs intended to serve a wide range of applications.  Today, many DSP families are focused on certain types of digital signal processing applications, such as control loops or audio equipment.  In this article, we’ll take a look at the current mainstream choices in DSP processors, and describe their key target applications and competitors.

It’s generally accepted that, for processing engines, there is a trade-off between efficiency and generality.  The more a chip is geared towards a specific application, the more efficient it’s likely to be (in terms of speed, energy consumption, and cost).  On one end of the spectrum you have traditional FPGAs, which are completely general-purpose, and on the other are fixed-function chips, which are completely application specific. In between these extremes lie various types of processors, including DSPs.

It’s generally accepted that, for processing engines, there is a trade-off between efficiency and generality.  The more a chip is geared towards a specific application, the more efficient it’s likely to be (in terms of speed, energy consumption, and cost).  On one end of the spectrum you have traditional FPGAs, which are completely general-purpose, and on the other are fixed-function chips, which are completely application specific. In between these extremes lie various types of processors, including DSPs.

While nearly all signal processing applications require some degree of software optimization, some applications require a sophisticated, multi-tiered optimization approach in order to meet their performance goals.

ARM’s general-purpose processor cores have long been used alongside DSP processors in products like cell phones, where the ARM core typically handles tasks like packet processing, user interface, and overall control, and the DSP handles the computationally demanding signal processing.  But as ARM has gradually upgraded its cores with DSP-oriented features, more chip and system designers are considering whether to use an ARM core as a DSP engine. The question is, how much signal processing work can an ARM core handle?

On March 5, Stretch, Inc. announced its second-generation software configurable processor family, the S6000, and two initial chips. With this offering—its first since the appointment last year of a new CEO—Stretch is mainly targeting video surveillance, video broadcast, and WiMAX basestation applications.