PAL is stands for Phase Alternating
Line. Walter Bruch was the engineer who invented the PAL system in the early
1960’s. It broadcasts in most countries at 576i. It has a refresh rate of 50Hz
and runs at 25 fps. Two advantages to the PAL system are Greater number of scan
lines and more picture detail. A disadvantage to PAL is more flicker because it
has a lower frame rate.
SESCAM stands for Squentiel couleur a
memoire, which is French for Sequential Colour with Memory. Invented in the
1960’s in France by a team, lead by Henri de France. SECAM is used in France,
Russia, parts of Asia and parts of Africa. SECAM has a resolution of 625 lines
and a refresh rate of 50Hz and runs at 25fps. Two advantages of SECAM are
stable Hues and contrast saturation and shares its ability to render images with
the correct hue with PAL. One disadvantage is half of the colour information is
lost on each line since only one colour signal is transmitted on each line.
NTSC stands for National Television
System Committee. It is used in mostly North America. Created by the FCC
(Federal Communications Commission) in 1940, it didn’t have colour. It has a resolution of 340 lines a
refresh rate of 60Hz and runs at 30fps. One advantage for NTSC is. One
disadvantage for NTSC is when PAL or NTSC is used on it, the video stutters.
Satellite television was created in 1962 by Arthur
C. Clarke. The broadcasting company sends the signal to satellites orbiting
space, the satellites then send the signal back to the satellite dish on
houses. Satellite TV can be accessed almost all over the world, due to the fact
that it can be fitted by anyone and isn’t needed to be connected to any other
place. Two advantages of satellite TV are High-quality audio and picture
display and access to hundreds of channels worldwide. One disadvantage is it
can malfunction in bad weather.
