DATV-Express Project – September update report

[KenW6HHC]

Charles G4GUO has continued to make great progress with the software on the first-prototype DATV-Express boards during the summer. The project's hardware board design appears to have the capability to go well beyond just DVB-S transmission, it should be able to transmit any waveform of up to 8 MHz bandwidth using SDR techniques. Not only is the DVB-S protocol software working well, but Charles has also tested 6 MHz DVB-T and DVB-S2 on the first-revision prototype board.

With DVB-T testing, the CPU load was much lower than had been expected. With DVB-S2 testing, the board appears to be currently supporting QPSK, 8PSK, 16APSK, and 32APSK modulation options for Normal frames (64800 bit frames) as well as the FEC code rates supported in the standard from 1/4 through 8/9.

Early DVB-S2 Constellation testing of 32APSK modulation

The current focus is on the etch-update to clean up some etch problems, especially the RF layout that required extensive rework to prevent self-oscillation. The team has just completed the set of design changes for the etch-update and has given the go-ahead to begin updating schematic-capture for the second-revision . The goal is to begin checking out revision two of the PCBA in December.

Charles plans to give a brief presentation on the DATV-Express Project progress and perform a demo of the prototype at the BATC Convention in October.

For more details, block-diagrams and photos, see the 2012 TAPR DCC presentation on DATV-Express. This PowerPoint file can be found in the OCARC DATV library at:

www.W6ZE.org/DATV/



Questions are welcome….de Ken W6HHC