Whats the difference between PAL, SECAM and NTSC?
In TVs the frame rate is dependent on the mains power supply frequency. There are two mains power supply frequencies used around the world, 50 Hz and 60 MHz. This divides worldwide TV standards into two main camps, 25 fps (at 50 Hz) and 30 fps (at 60 Hz). The inception of colour broadcasting brought about further sub-divisions in these camps as different systems were invented to carry the colour part of the signal. Most 60 Hz countries (including the USA, Canada and Japan) adopt the NTSC (National Television Standards Committee) colour system. This colour system is perfectly adequate for closed circuit situations but in broadcast environments it can exhibit problems. To overcome this, a modified version of NTSC was introduced which is known as the PAL (Phase Alternate Lines) colour system. This has been adopted by most 50 Hz countries (including the UK and most other European countries). There is also another colour system in widespread use amongst 50 Hz countries. The SECAM (Sequentia
