Monochrome vs Color vs Digital TV
The best way to explain basic television is with the monochrome model. The development of color TV left the B&W model intact, and simply added a chroma signal to the existing luma (luminence) signal and modulated them together. The color TV demodulates them into separate signals - and then uses the same signal as B&W TV for scanning, retracing, and synch.
So if you understand monochrome, it is a simple leap to understanding color television. The three colors, RGB, are scanned across your screen at the same speed as the monochrome info - but the resolution is not as sharp.
Unless stated - the numbers, resolutions, etc. that follow are all for monochrome TV !!!
Digital Television has multiple formats that have been developed - but most of the excitement is ceneterd around HDTV (High Definition TV).