Digital Creations never released a technical description of the brilliant DCTV hardware, but I suspect it is based on the same principles Hewlett Packard used to increase the color resolution for some of their workstations. I have a copy of the HP patent somewhere, and it could probablybe found online.
There was some controversy that HAME technology was lifted for AGA. Anyway, Ben Williams and Black Belt Systems is still around, alive and kicking - try:
info@blackbeltsystems.com
Although I don't think Ben even has an Amiga anymore.