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<DIV><FONT face=Arial size=2>Sent this to the list several weeks ago, apparently
it is in use in RC cars now but no mention of RC airplane application yet.
</FONT></DIV>
<DIV><FONT face=Arial size=2>Ed M.</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=pattern4u@comcast.net href="mailto:pattern4u@comcast.net">Grow
Pattern</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, February 16, 2005 1:54
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> DSM</DIV>
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<DIV>Just read this. <EM>"VERRRYY interesting, gutten nacht</EM>
<EM>liebschen..."</EM></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV>Advancing RC Technology To The Next Generation</DIV></TD>
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<TD class=mttl>Written by: John Adams, Horizon Hobby Engineering
Manager</TD>
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<P>AM, FM, PCM and now DSM. Spektrum’s newly released DSM (Digital
Spectrum Modulation) system advances RC radio technology to the
next generation. Based on an optimized version of Direct
Sequencing Spread Spectrum, DSM offers pure digital control
providing an impenetrable radio link that’s immune to all types of
interference. And with 4096 bit resolution and 5.6ms response
time, the DSM system offers seemingly infinite accuracy and
instantaneous response for a totally connected driving experience.
</P>
<P><B>WORLD’S MOST SECURE RADIO LINKS</B></P>
<P>For the highest security levels of radio communications, NASA,
the U.S. military and government agencies like the CIA and FBI
rely on Spread Spectrum technology. Whether guiding unmanned
reconnaissance aircraft over enemy territory, controlling
satellites in space or communicating critical mission orders to
the battlefield, the impenetrable secure link that Spread Spectrum
coding provides makes it ideal for these decisive security
applications. </P>
<P>And now Spektrum offers this technology for your RC car’s radio
system.<BR><BR></P>
<P><B>SPEKTRUM'S DSM TECHNOLOGY</B></P>
<P>In development for over four years, Paul Beard, a leading
engineer in the Spread Spectrum industry, designed Spektrum’s DSM
system. The DSM system utilizes Direct Sequencing Spread Spectrum
technology that has been optimized for RC car use. Unlike current
narrow band 27 and 75MHz systems, Direct Sequencing Spread
Spectrum or DSSS generates a wide signal on a single frequency,
and information is encoded with its own Globally Unique
Identification number (called GUID) such that the receiver only
recognizes the information from its specific transmitter. And with
over 4.2 billion available GUID codes, it is virtually impossible
for a receiver to be controlled by anything other than its mating
transmitter. Spektrum calls this optimized form of modulation
DSM–Digital Spectrum Modulation.</P>
<P><BR><B>DSM SYSTEM SPECIFICATIONS</B></P>
<UL>
<LI>Frequency Band 2.400–2.4835GHz
<LI>Channels 79
<LI>Channel Spacing 1MHz
<LI>Range 3000 ft
<LI>Latency 5.6 ms
<LI>Resolution/Channel 4096 steps </LI></UL>
<P><B>DSM RECEIVER VB SPECIFICATIONS</B></P>
<UL>
<LI>Weight .40 oz/ 11.3 g
<LI>Dimensions (LxWxH) 1.62x 1.06x.57”/ 41.2x 27.0x 15.3mm
<LI>Input Voltage 3.2–9.6V
<LI>RC Channels 3
<LI>Current 40 mA @ 4.8V
<LI>Antenna Length 8.5 in<BR><BR></LI></UL>
<P><B>ULTRA HIGH FREQUENCY ADVANTAGE</B></P>
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<P>The Spectrum DSM system operates in the ultra high 2.4GHz ISM
(Industry, Science and Medical) band. This ultra high frequency
offers several advantages over conventional 27 and 75MHz systems.
First, all model-generated radio interference from noisy motors,
speed controllers, bad bearings, metal-to-metal noise, etc. exists
below 300MHz. At 2.4GHz (that’s 2400MHz) the operational frequency
range of the Spectrum system is 8 times higher than the range of
this model-generated RF noise, making the system immune to these
types of interference. Secondly, 2.4GHz is an internationally
accepted band, so it’s not necessary to change radio equipment
when traveling to overseas events.And because the 2.4GHz
wavelength is very short, the required lengths of the antennas are
much shorter. The receiver antenna is 8.5” and can be cut down to
3.6” if desired, making antenna mounting within the body easy. The
transmitter antenna is a mere 3.5” long, eliminating the “fishing
rod” that normally extends into view. </P>
<P>FCC learned valuable lessons from other bands and applied those
lessons to the 2.4GHz band. And unlike the 27 and 75MHz band, the
FCC limits the power output in this 2.4GHz to a maximum of 1watt,
thus preventing other 2.4GHz systems from overpowering each other.
In other words, there are no “high power” commercial users
interspersed in the 2.4 GHz band. <BR><BR></P>
<P><B>THE BENEFITS OF DSM</B></P>
<P>Spektrum’s DSM system eliminates all types of radio
interference, including model-generated noise from motors, ESCs,
bad bearings, etc. and from outside sources like pagers, cell
phones, wireless computer systems and other RC radio systems, and
offers these benefits:</P>
<UL>
<LI>No more waiting for an open frequency—just turn it on
<LI>Ultra fast 5.6ms response time
<LI>No tuning or maintenance to perform (ever)
<LI>Built-in fail-safe drives servos to preprogrammed position
if signal is lost
<LI>Ultra precise 4096 bit resolution
<LI>Operates on international 2.4GHz ISM band so no need to
change bands when traveling to international races
<LI>Short 8.5” or 3.6” receiver antenna length and 3.5”
transmitter antenna length
<LI>40% less current draw with the transmitter means 40% more
battery life
<LI>Telemetry ready for rpm/speed, temperature, battery voltage,
lap times and signal strength
<LI>Legal for most racing organizations including ROAR, NORRCA
and IFMAR
<LI>Available for most popular 3-channel module radio systems
for easy, inexpensive conversion to DSM technology </LI></UL>
<P><BR><B>FHSS VS. DSSS</B></P>
<P>There are two primary types of Spread Spectrum technology—
Frequency Hopping (FHSS) and Direct Sequencing (DSSS). FHSS
systems transmit a narrow band signal and rapidly jump from one
frequency to the next spending a few milliseconds on each
frequency. DSSS systems transmit on a single selected frequency
but on a very wide band. Only a small portion of that band is used
for specially encoded information. Originally, Spektrum engineers
started their development with FHSS-based systems because they
were relatively easy and inexpensive to develop. However, it was
soon discovered that FHSS had several limitations that would
prevent it from being the optimal solution for RC. </P>
<P>While more difficult and costly to develop, our engineers began
experimenting with Direct Sequencing Spread Spectrum and optimized
the modulation scheme to overcome critical response and re-link
issues. In addition, DSSS offered 18dB increase of processing gain
for significant improvements in range. With years of development
and testing the DSSS modulation scheme was optimized for RC car
use and Spektrum’s DSM system was
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