DVB TT Budget Patch
DVB-x Technotrend FF card Budget Patch
This hardware modification, allow to add the capability of get the full Transport Stream (TS), of the tuned transponder, to a Full Function (FF) DVB card, while the rest of the functions of the FF card remains unaltered.
Basically, the MPEG2 Demodulator outputs in the tuner must be connected to the free Digital Video port D1B in the SAA7146, as is done on TT_budget cards. On this budget cards, two IC's are used to generate a pseudo VSYNC signal for the "frame adquisition" of the TS packets "lines"; but with the resources in the SAA7146, this IC's can be avoided, using the RPS1 to generate VSYNC on the GPIO3 line (also free on all cards that I know, but maybe not on old Siemens DVB-C with the Analog module), which then is connected to D1B_VSYNC input.
To make the 12 connections need, a small PCB (26*5mm) can be inserted between the tuner and the SAA7146 pins, making the soldering much more easy that using discrete wires (the SAA7146 pins are at 0.65mm raster!).
On the software side, the SAA7146 is setup to do the packet adquisition and the RPS1 to generate the VSYNC signal; the DVB driver must read and demultiplex the packets, as done on budget cards.
More details can be found on this file (local copy), which is the first (and unique for now) "documentation" of when this idea was developped; please note that this file is old (I patched the DVB drivers and now there is a budget-patch module in DVB_kernel) and that some Oops that I had now could be already solved.