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<p class="MsoNormal"><span lang="EN-US">DATV-Express Project – March update report<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Charles Brain G4GUO has completed a new YouTube video to describe the Digital Amateur Television Version 2 PCBA
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Art WA8RMC finished performing the basic electrical tests with the "testing software" on the new "first-article" prototype PCBA and found everything working as planned. Art was successful in producing 18.6 dBm of output
on 1.3 GHz in early March… and then sent the board to Charles G4GUO to begin more thorough testing and to begin making some software changes.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Charles had the new board transmitting DVB-S and DVB-S2 video within a couple of hours after Parcelforce delivered the box to his QTH. Charles's first reports included:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• Min operating frequency 72.5 MHz<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• Max operating frequency 2.48 GHz<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• Noise sidebands -55db (about 30db better than previous board)<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• Very clean QPSK constellation<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I have added three new photos using the new v2 board to the PHOTOS area of this Yahoo Group, in the "DATV-Express Project" album. the photos show first DVB-S video received, the clean QPSK constellation achieved with
new etch and a spectrum view of the new board.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">During March, Charles was able to accomplish quite a lot of improvements to the DATV-Express software design, as he has summarized below:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Host code<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• Now being compiled under Ubuntu 12.04 LTS<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• Development environment has been updated to Qt5.01 Creator<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">FX2 code<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Added proper support for USB2 VBUS monitoring<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">FPGA code<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• Interpolation increased from x4 to x8<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• Pulse shaping filter increased to 95 taps (root raised cosine compensated response).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• Programmable symbol rate generator added with the current range 2 MS/sec to 6 MS/sec in fractional steps.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• I2C configuration of modulation parameters has been added<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• Delayed IQWRT clock added.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">• DAC has so far been tested up to 48 Msamples/sec<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">No etch errors have been found in the second layout, so huge compliments are deserved by our PCB layout guru, Tom WB6P. Art WA8RMC is busy building up a second prototype board. Charles also has plans to get the entire
DVB-S protocol to run on the FPGA rather than on the Linux host PC. That way…the whole host thing can also be run on a small ARM-based computer, like a Raspberry Pi or perhaps the MK808.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">"full speed ahead"...de Ken W6HHC<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Watch DATV-Express Version 2 PCBA<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">http://www.youtube.com/embed/OXh-anABYaU?rel=0<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Digital Amateur TV Yahoo Group <o:p></o:p></span></p>
<p class="MsoNormal">http://groups.yahoo.com/group/DigitalATV<o:p></o:p></p>
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