2. tv signal format – Sony SAT-HD200 User Manual

Page 11

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Signal Format

Analog (NTSC)

Digital (ATSC/DIRECTV)

SD

HD

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2-2. TV Signal Format

The digital TV standards allow several different formats. Broadcasters can choose between

three formats:

• 480p - The picture is 704 x 480 pixels, sent at 60 complete frames per second (480i is

also possible).

• 720p - The picture is 1280 x 720 pixels, sent at 60 complete frames per second.

• 1080i - The picture is 1920 x 1080 pixels, sent at 60 interlaced frames per second (30

complete frames per second).

(The “p” and “i” designations stand for “progressive” and “interlaced.” In a progressive for-

mat, the full picture updates every sixtieth of a second. In an interlaced format, half of the pic-

ture updates every sixtieth of a second.)

The 480p and 480i formats are called the SD formats, and 480i is roughly equivalent to a nor-

mal analog TV picture. The 720p and 1080i formats are called the HD formats.

Some NTSC televisions can display a picture 720 pixels wide by 480 pixels high, that’s a total

of 345,600 pixels. HD digital signals can have a maximum resolution of 1920 x 1080, that’s

2,073,600 pixels, or six times more pixels than the older resolution. Pictures will be crisper and

cleaner, with more detail in every close-up and every panorama.

Standard Comparison Table

Active Lines

480i

480p

720p or 1080i

Sound

Stereo (2 ch)

Dolby Digital (5.1 ch)

Dolby Digital (5.1 ch)

MPEG Audio (2 ch)

Aspect Ratio

4 : 3

4 : 3 or 16 : 9

16 : 9

Resolution

720 x 480

640 x 480

1280 x 720

704 x 480

1920 x 1080

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