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<DIV dir=ltr align=left><SPAN class=590135620-16022005><FONT face=Arial
color=#0000ff size=2>There are some issues to work out before you could use it
in airplanes.. the major one being the antennae are very directional. That
doesn't mean it's not possible.. just that there are hurdles to
overcome.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=590135620-16022005><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=590135620-16022005><FONT face=Arial
color=#0000ff size=2>-Doug</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=590135620-16022005><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=590135620-16022005></SPAN> </DIV><BR>
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<FONT face=Tahoma size=2><B>From:</B> discussion-request@nsrca.org
[mailto:discussion-request@nsrca.org] <B>On Behalf Of </B>Ed
Miller<BR><B>Sent:</B> Wednesday, February 16, 2005 11:18 AM<BR><B>To:</B>
discussion@nsrca.org<BR><B>Subject:</B> Re: DSM<BR></FONT><BR></DIV>
<DIV></DIV>
<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>
<DIV><BR></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
born.<BR></P></TD></TR></TBODY></TABLE></TD></TR></TBODY></TABLE></FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>