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Bier: “(DSP) is becoming less of a distinct,
discrete technology due to integration.”
processor portfolio, ranging from power
efficient devices to high performance
parts. Flexible and efficient processors
offer a great opportunity to innovate and
overcome challenges.”
Rick Gentile, who leads Analog Devices’
processor applications group, noted: “We
still see customers on both sides of the
spectrum. Some use our processors to
perform a signal processing function, some
use our processors to perform more of a
controller function. More than two thirds
use our processors to do some combination
of both. In that sense, the application lines
blur and dsps and microcontrollers are
Is this a problem? “I don’t think so,”
said Gentile. “Programmers are in control
of what gets implemented in their system.
The migration path to a processor that
performs signal processing and control is
done at their own pace. In some cases, it
happens immediately, in others, it
happens more slowly. Either way, the
flexibility to balance the type of work the
processor does is important. The
challenge from a tools and processor
architecture standpoint is to make these
worlds peacefully coexist. It has to be
easy to take advantage of the increase in
flexibility.”
“Far from being a problem,” Dhanani
contended, “fpgas are expanding the
overall dsp market. DSP is one of the
fastest growing applications for fpgas and
DSPearing act?
Is the digital signal processor becoming an endangered species or is its future assured? By Graham Pitcher.
J
ump back a decade or more and
there was little difficulty identifying
just what digital signal processing
was. Neither was there any problem in
identifying a digital signal processor.
But times change. Today, digital signal
processing as a technique is beginning to
disappear from view, hidden within
applications. Whilst digital signal
processors (dsps) are still being
produced, they are beginning to evolve
into different types of device – witness
Texas Instruments’ launch a couple of
years ago of the DaVinci platform.
So is digital signal processing
disappearing as an identifiable technique
and are dsps likely to disappear as
discrete devices?
Elizabethe de Freitas is dsp catalogue
business development manager EMEA for
Texas Instruments. “We have a broad
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becoming less visible.”
Jeff Bier, president of analysis and
benchmarking company Berkeley Design
Technology (www.bdti.com), commented:
“I’m not sure about it being ‘invisible’, but
it is becoming less of a standalone
technology.”
So what is happening? Bier explained:
“It is becoming less of a distinct, discrete
technology due to integration. It is rare
today to find a system that does nothing
but digital signal processing. Typically, it
is combined with other things, like user
interface, packet processing and storage
management.”
Another reason is the emergence of
the fpga as a dsp platform. “One fpga
brings the performance of a dsp farm to
an application,” said Suhel Dhanani,
Altera’s senior product marketing
manager, IP and Technology.
de Freitas: “Making systems smaller and more
efficient ... is a clear application for discrete dsps.”
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SPECIAL REPORT
Expert panel
a key initiative for Altera.”
With signal processing becoming more
prevalent in a range of applications, will
all processors need to offer dsp
functionality? Bier: “In effect, all
processors already offer dsp
functionality. There’s nothing preventing
an engineer from implementing dsp tasks
on a purely general purpose cpu –many
early MP3 players used an ARM7 for audio
processing – or on a general purpose
fpga. Given the importance of dsp in
many applications, it often makes sense
to have a processing element tuned
particularly to dsp tasks. This usually gets
you better performance,
cost/performance and energy efficiency.”
Gentile took a similar view. “I have
seen customers that needed to perform
signal processing and they just couldn’t
do it on their previous controller focused
designs. At the same time, in the
embedded space, cost and power still
drive decisions, so you don’t have some of
the higher end options open to you.”
What is the advantage of dsp being
performed in an fpga? Dhanani claimed:
“In one word; ‘performance’. This also
results in lower system power
consumption, lower price and higher
integration. The alternative is multiple
dsps.
“Design engineers are aware that
fpgas have a performance advantage,” he
continued. “What gets missed is that, by
doing the job of tens of dsps, a signal
processing system built using fpgas also
has a significantly lower BoM and overall
power consumption.”
Has algorithmic complexity affected
the dsp’s evolution? “That's a good
question,” Bier responded. “Algorithms
have become more complex as algorithm
developers have built on the work of
earlier algorithm developers, and as
higher performance processors have
made it practical to deploy more complex
algorithms. Often, these more complex
algorithms do more than conventional
signal processing. For example, in H.264,
you have some rather complex entropy
coding techniques that are very
demanding of processing resources. A
Dhanani: “DSP is one of the fastest growing
applications for fpgas.”
consequence of this is that, in some
cases, the performance advantages of
dsps are lessened, because they’re not as
good at, say, entropy coding, as they are
at things like discrete cosine transforms.”
Dhanani took up the theme. “Motion
estimation, which underlies the coding
efficiency for H.264 algorithms, relies on
billions of sum of absolute difference
calculations per frame to make the
encoding decisions. Taken by itself, each
operation is straightforward. But
algorithmic complexity comes from the
amount of computation done per frame to
get the most efficient encoding.”
Gentile offered: “It has to be easy to
develop and debug development of
complicated algorithms. It also has to be
easy to add some other functions as well,
or the application will be a candidate for
an asic.”
What about the future? Will dsp have a
role to play?
Dhanani believed: “As we go forward,
the dsp market will see increasing
fragmentation. All these platforms –
general purpose processors, dsps, fgpas
and asics – have an important role to play
and it will be the nature of the algorithm
that ultimately decides the optimal signal
processing platform.”
“More integration, more flexibility to
www.newelectronics.co.uk 8 July 2008
move across the highest and lowest ends
of the processing spectrum and easier
integration with signal chain products,”
said Gentile.
de Freitas added: “TI sees the need to
reduce system power consumption, ‘go
green’, develop great user interfaces and,
at the same time, offer SoCs and multicore
devices to offer greater flexibility.”
So, will discrete dsps disappear? de
Freitas: “TI has a long history of
innovation; making systems smaller and
more efficient and extending battery life
while continuing to increase performance
– in audio devices, for example. This is a
clear application for discrete dsps.”
Gentile’s opinion: “Discrete dsp
solutions are still very much in use in
active designs, we just see more and more
‘dual use’ applications.”
Bier concluded: “They’ll be around for
the foreseeable future, for a number of
reasons. In many systems, it will make
sense to have a cpu and a dsp. And for
applications that are heavily signal
processing based, and that can get by with
a single processor, dsps are often the best
solution due to their performance
attributes and signal processing oriented
development infrastructure.
“However, I expect the number of new
system designs using discrete dsps will
decline as a percentage of total processor
based system designs.” ■
Gentile: “Discrete dsp solutions are still very
much in use in active designs.”
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