Lay usage will drive high tech DSP

Applications software, used in mass marketed products like cell phones and in specialised products like sophisticated cameras that can one day help the blind, is driving the architecture of digital signal processing (DSP) chips, says Ray Simar, a scientist from Texas instruments (TI).

DSP chips, as the name suggests, play a key role in processing digital electronic signals and sit at the heart of IT.

Forward Concepts (FC), a US-based market researcher that forecasts strong growth in the DSP market, named TI as one of four companies dominating the general purpose DSP segment. A large chunk of it is accounted for by exploding volumes in cellular phones. In 2003, FC forecast the $6 billion general purpose DSP market to grow by 25 per cent in 2004.

Embedded DSP, with software burnt into semiconductor chips to run devices like DVD players and Internet video phones, was another $10 billion market, FC said, with over 100 vendors selling technologies. They include Bangalore-based Ittiam Systems.

Simar, a TI Fellow (one of a small group of senior scientists at the company), points out what is often overlooked "" architecture will be driven by applications and not the other way round. So it will be driven by the challenge to pack more into less as more sophisticated technologies get built into cell phones for instance. This will take up much of the time of companies.

This will translate into technical challenges posed by things like smaller transistors and leakage current. Commercial chips need to work with leakages of less than 5 per cent. But, "There are applications where up to 20 per cent of the power is lost," Simar says.

Take cellular phones, which are idle most of the time. That time is dominated by power leakage. This leads to solutions like "turn the memories off when the phone is idle", allowing for less frequent battery recharge, he says. Interconnect, between circuits and gates, poses another challenge.

So, one trick to make integrated chips do better is pipelining. This involves breaking up a circuit into segments. When one segment is working, the one that preceded it can take another set of instructions, he says.

Challenges of dealing with more integration apart, the present ways of making things, based on combined metal oxide semiconductors (CMOS) will continue, Simar says, "I don't see any imminent end to it. There is no dearth of applications based on it, in the near future. Perhaps they will be used for several decades, though people are considering optical chips, carbon fibres and a variety of other things."

With CMOS, while the bulk semiconductor is okay, there are many changes popping up at the micro level. The trick is to learn to live in harmony with these changes. The smaller the geometry, the bigger the change, explains Simar.

In cellular phones, TI is working on OMAP (open media application platform), a way of getting finer features via. greater integration. For instance, put both a general purpose processor and a reduced information set processor, which is a lower powered processor, together. This could make the phone smaller and reduce manufacturing costs.

There would also be reduced lengths of wires in the circuits, so decreased power consumption. "OMAP is the beginning of a trend," Simar foresees. Such innovations in making the chip and therefore the final product more efficient would dominate the foreseeable future for large DSP technology companies.