Television Fundamentals Television Broadcast Standards

Comparison of Television Standards

1. National Television Standards Committee

(NTSC)

a. Higher Frame Rate -

Use of 30 frames per second (really 29.97) reduces visible

flicker.

b. Atomic Color Edits -

With NTSC it is possible to edit at any 4 field boundary

point without disturbing the color signal.

c. Less inherent picture noise -

Almost all pieces of video equipment achieve better signal

to noise characteristics in their NTSC/525 form than in their

PAL/625.

National Television Standards

Committee (NTSC)

a. Lower Number of Scan Lines -

Reduced clarity on large screen TVs, line structure more

visible.

b. Smaller Luminance Signal Bandwidth -

Due to the placing of the color sub-carrier at 3.58MHz,

picture defects such as cross-color, and dot interference

become more pronounced.

National Television Standards

Committee (NTSC)

c. Susceptibility to Hue Fluctuation -

Variations in the color subcarrier phase cause shifts in

the displayed color, requiring that the TV receivers be

equipped with a Hue adjustment to compensate.

d. Lower Gamma Ratio -

The gamma value for NTSC/525 is set at 2.2 as

opposed to the slightly higher 2.8 defined for PAL/625. This

means that PAL/625 can produce pictures of greater

contrast.

National Television Standards

Committee (NTSC)

The oldest existing standard, developed in the

USA. First used in 1954.

Consists of 525 horizontal lines of display and 60

vertical lines.

Sometimes irreverently referred to as Never Twice the Same Color.

Only one type exists, known as NTSC-M.

Phase Alternate/Alternation by

Line (PAL)

a. Greater Number of Scan Lines -

more picture detail.

b. Wider Luminance Signal Bandwidth

The placing of the color Sub-Carrier at 4.43MHz allows a

larger bandwidth of monochrome information to be

reproduced than with NTSC/525.

Phase Alternate/Alternation by

Line (PAL)

c. Stable Hues -

Due to reversal of sub-carrier phase on alternate lines, any

phase error will be corrected by an equal

and opposite error on the next line, correcting the original

error.

d. Higher Gamma Ratio -

The gamma value for PAL/625 is set at2.8 as opposed

to the lower 2.2 figure of NTSC/525. This permits a higher

level of contrast than on NTSC/525 signals.

Phase Alternate/Alternation by

Line (PAL)

a. More Flicker -

Due to the lower frame rate, flicker is more noticeable on

PAL/625 transmissions; particularly so for people used to

viewing NTSC/525 signals.

b. Lower Signal to Noise Ratio -

The higher bandwidth requirements cause PAL/625

equipment to have slightly worse signal to noise

performance than it's equivalent NTSC/525 version.

Phase Alternate/Alternation by

Line (PAL)

c. Loss of Color Editing Accuracy -

Due to the alternation of the phase of the color signal,

the phase and the color signal only reach a common point

once every 8 fields/4 frames. This means that edits can

only be performed to an accuracy of +/- 4 frames (8 fields).

Phase Alternate/Alternation by

Line (PAL) PAL was developed by German engineer Walter

Bruch and the German electronic corporation Telefunken. Walter Bruch patented his invention

1963 and the first commercial application of the PAL

system was in August 1967. Also a 625/50-line

display and variant of NTSC.

Proponents call it "Perfection At Last." Due to the

cost of the enormous circuit complexity, critics often

refer to it as "Pay A Lot".

Sequential Color with Memory

(SECAM)

Sequential Couleur Avec Mmoire

a. Stable Hues and Constant Saturation -

SECAM shares with PAL the ability to render images with

the correct hue, and goes a step further in ensuring

consistent saturation of color as well.

b. Higher Number of Scan Lines -

SECAM shares with PAL/625,the higher number of scan

lines than NTSC/525.

Sequential Color with Memory

(SECAM)

a. Greater Flicker -

Same with PAL/625

b. Patterning Effects -

The FM subcarrier causes patterning effects even on non-

colored objects.

c. Lower monochrome Bandwidth -

Due to one of the two color sub-carriers being at 4.25MHz

(in the French Version), a lower bandwidth of monochrome

signal can be carried.

Sequential Color with Memory

(SECAM)

SECAM was developed in France. First

used in 1967. A 625-line vertical, 50-line

horizontal display.

Sometimes referred to by wags as

"Something Essentially Contrary to the American Method" or SEcond Colour Always Magenta!"