The signal is NTSC, digitized and compressed via a proprietary format and decompressed by a set-top box.
Luminance Signal - That portion of the NTSC color television signal which contains the luminance Signal - That portion of the NTSC color television signal which contains the luminance or brightness information.
Most modern pal DVD players convert NTSC into the PAL format.
For example, if you have a North American PSP with the NTSC firmware, then you can only read comics purchased for that firmware.
However, the version for the Sega Master System fetches anywhere from $200 to $500 for the NTSC version of the game.