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Design Challenges: Avoiding the Pitfalls, winning the game - Xilinx

Design Challenges: Avoiding the Pitfalls, winning the game - Xilinx

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interfaces available, Microsoft intentionally<br />

designed a flexible solution that allows<br />

rapid changes to <strong>the</strong> back-end vehicle<br />

interface without affecting <strong>the</strong> underlying<br />

architecture and performance of <strong>the</strong> system.<br />

For example, in <strong>the</strong> future it would be<br />

possible to adapt <strong>the</strong> FPGA solution to suit<br />

<strong>the</strong> needs of <strong>the</strong> end application with automotive<br />

buses such as MOST, IDB-1394, or<br />

ano<strong>the</strong>r digital vehicle network.<br />

Voice Recognition System<br />

Central to <strong>the</strong> Microsoft Telematics<br />

Platform is <strong>the</strong> voice recognition (VR) system.<br />

The audio signal path within any VR<br />

system is analog biasing/filtering, digitization,<br />

and digital filtering before <strong>the</strong> signal<br />

is finally presented to <strong>the</strong> VR engine for<br />

speech processing.<br />

Within this path, multiple opportunities<br />

exist for unwanted noise to be introduced<br />

into <strong>the</strong> system (both onboard <strong>the</strong><br />

electrical platform and within <strong>the</strong> vehicle<br />

environment even before <strong>the</strong> electronics).<br />

Both <strong>the</strong> product developer and <strong>the</strong> vehicle<br />

manufacturer must ensure that <strong>the</strong> microphone<br />

position and type are correctly suited<br />

to <strong>the</strong> application and environment.<br />

In a perfect world, <strong>the</strong> VR engine will<br />

receive clean, consistent speech signals –<br />

but given <strong>the</strong> dynamic nature of <strong>the</strong> vehicle<br />

environment, acceptable voice recognition<br />

implementation is not a straightforward<br />

exercise. Factors such as vehicle speed, window<br />

position (open/closed), road noise,<br />

and wea<strong>the</strong>r conditions (rain/wind) only<br />

add to already difficult VR problems such<br />

as languages, accents, and gender. These<br />

added factors have increased <strong>the</strong> importance<br />

of preconditioning using highly<br />

adaptive digital filtering algorithms before<br />

<strong>the</strong> signal is presented to <strong>the</strong> VR engine.<br />

Microsoft chose to implement this signal<br />

preconditioning in hardware and take<br />

advantage of <strong>Xilinx</strong> parallel DSP processing.<br />

Spartan-3 FPGAs, with as many as<br />

104 embedded 18-bit multipliers, are ideal<br />

for implementing compact DSP structures<br />

such as MAC engines, distributed arithmetic<br />

FIR filters, and fully parallel FIR filters<br />

in a low-cost device.<br />

Microsoft also offloaded processorintensive<br />

software filtering into hardware.<br />

Of course, this pre-processing is possible in<br />

ASSPs such as dedicated DSP chips. But<br />

<strong>the</strong> benefits gained through high levels of<br />

integration in o<strong>the</strong>r parts of <strong>the</strong> platform<br />

would be lost.<br />

The combination of telematics and VR<br />

allows implementations of adaptable and<br />

upgradeable VR engines and DSP filters<br />

tailored to suit certain types of users and<br />

environments (Language: English, Accent:<br />

Scottish, Gender: Female).<br />

The importance of designing automotive<br />

products (especially in <strong>the</strong> infotainment<br />

section of <strong>the</strong> vehicle) with sufficient<br />

spare bandwidth to cope with new and<br />

unexpected future upgrades also applies to<br />

<strong>the</strong> FPGA. It is now becoming clear to<br />

automotive OEMs that architectures that<br />

allow for flexible and scalable firmware are<br />

a necessity in future platforms.<br />

Although not currently implemented<br />

in <strong>the</strong> Microsoft platform, it would be<br />

possible to easily add soft processors to<br />

act as system co-processors. Just as <strong>the</strong><br />

DSP processing was offloaded from <strong>the</strong><br />

main processor in Microsoft’s design, it<br />

would also be possible to use embedded<br />

processors (such as <strong>the</strong> <strong>Xilinx</strong> 32-bit<br />

MicroBlaze soft processor or 8-bit<br />

PicoBlaze microcontrollers) to take<br />

some of <strong>the</strong> processing load from <strong>the</strong><br />

main system processor.<br />

FPGAs for Automotive Applications<br />

In-car electronics have seen tremendous<br />

growth in recent years, not only in traditional<br />

body control and engine management<br />

but in <strong>the</strong> new areas of driver<br />

assistance systems and telematics applications.<br />

Figures recently published by <strong>the</strong><br />

IEEE indicated an annual increase in car<br />

electronics of 16%, with a prediction that<br />

by 2005 electronics will account for 25%<br />

of <strong>the</strong> cost of a mid-size car.<br />

Telematics systems exhibit characteristics<br />

more like those of consumer products –<br />

short time to market, short time in market,<br />

and changing standards and protocols.<br />

These issues impact <strong>the</strong> way engineers<br />

approach designs and select <strong>the</strong> hardware<br />

needed to quickly create, iterate, and support<br />

future upgrading.<br />

FPGA technology can now solve <strong>the</strong>se<br />

requirements. <strong>Xilinx</strong> is committed to serving<br />

telematics and car infotainment applications<br />

through its <strong>Xilinx</strong> Automotive (XA)<br />

family, which delivers:<br />

• Extended temperature ranges – up to<br />

125°C<br />

• Full production part approval process<br />

(PPAP) support<br />

• Industry-recognized AEC-Q100 devicequalification<br />

flow<br />

• Compliance with <strong>the</strong> worldwide automotive<br />

quality standard ISO TS 16949,<br />

as well as Pb-free packaging to meet <strong>the</strong><br />

RoHS directive<br />

These devices, based on our Spartan<br />

family of FPGAs, are ideal for digital<br />

designs requiring low cost per logic cell<br />

(system gate), low cost per I/O, and<br />

advanced features such as multiple I/O<br />

standards on a singe device and embedded<br />

multipliers for high-speed DSP.<br />

Conclusion<br />

Backed by a commitment from supporters<br />

such as <strong>the</strong> Microsoft Automotive Business<br />

Unit and <strong>Xilinx</strong> Automotive, <strong>the</strong> vision of<br />

Microsoft’s Telematics Platform is now<br />

becoming a reality. The convergence of key<br />

technologies is being adopted today by<br />

first-tier automobile manufacturers in a<br />

platform that enables:<br />

• A valuable and affordable telematics solution<br />

• Reliable connectivity through wireless<br />

networks<br />

• High-quality voice recognition<br />

• A broadly supported operating system<br />

for application developers<br />

• Low-cost hardware<br />

This is giving rise to a “virtuous cycle” of<br />

continuous investment by developers, who<br />

will use <strong>the</strong>se platforms to create even more<br />

value for end users.<br />

For more information, visit<br />

www.microsoft.com/automotive/<br />

windowsautomotive/about.mspx/ and www.<br />

xilinx.com/automotive/.<br />

Third Quarter 2005 Xcell Journal 43<br />

$<br />

TOTAL COST

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