DATV-Express Project – December update report

[KenW6HHC]

The DATV-Express team has made all of the last-minute tweaks to the schematic capture file for the new second-revision board layout. Tom WB6P was given the go-ahead to use the new schematic file for the PCB layout efforts…and is now very busy producing the new gerber files using the PADS PCB layout tool. This a totally new layout effort...not a tweak. The next hardware step is a design review for the draft PCB layout and then building up a few new protoype boards.

Meanwhile, Charles G4GUO has been productive in turning his software efforts toward the Windows-32 bit OS. Charles has sorted out enough to use GraphEdit to capture video from a Hauppauge card on Windows7 and is now working towards the Windows DirectShow Environment. It was good for Charles to get some filter graph suggestions from Brian G4EWJ (of the DigiLite team). The advantage of using DirectShow is that manufacturers support Windows before they support Linux and if they are producing Media devices they have to provide DirectShow components. If we create a Filter for DATV-Express, then DATV-Express would simply appear as a component that can be linked in, it would replace the UDP Sender filter. This would make it very flexible and would allow us to use all sorts of 3rd party devices / components. We could for example use it with MPEG4 or a different capture card.

Charles also worked on the high speed USB2 handling under Windows and managed to output a sample stream from a Windows7 PC to the DATV-Express card without any dropouts at 4M samples per sec. So that is the last part of the puzzle as far as Windows is concerned. DATV-Express on Win32 can be done!!

Finally, the “educated finger” of Charles sorted out that the rework wires on the Modulator PLL feedback loop filter appear to be picking up nearby noise on a very high impedance chip circuit. This may be the source of our annoying sidebands noise…and should be cleaned up with new etch layout.

“Full speed ahead”…de Ken W6HHC