IEI Technology iSignager-LCD-15S, Руководство пользователя

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ISignager-LCD-S Series Digital Signage Display
Page 41
A.5.1 Notation
In the context of HDTV, the formats of the broadcasts are referred to using a notation
describing:
720 p 60
720: The number of lines in the display resolution.
P: Progressive frames (p) or interlaced fields (i).
60: Number of frames or fields per second.
For example, the format 720p60 is 1280x720 pixels, progressive encoding with 60 frames
per second (60 hertz known as Hz). The format 1080i50 is 1920x1080 pixels, interlaced
encoding with 50 fields (25 frames) per second. Often the frame or field rate is left out.
It can then usually be assumed to be either 50 or 60, except for 1080p which is only
supported as 1080p24, 1080p25 or 1080p30 by consumer HDTV displays.
A frame or field rate can also be specified without a resolution. For example 24p means
24 progressive frames per second and 50i means 50 interlaced frames per second.
A.5.2 Progressive Scan vs. Interlaced Scan
Interlaced scan is the way a television decodes an image–a frame is broken into two fields,
odd (1, 3, 5, 7…) and even (2, 4, 6, 8…). A television scans 60 fields per second with 30
odd and 30 even fields created. By combining the two fields every 1/30 of a second, a
frame is created thus creating 30 frames per second.
Progressive scan differs from interlaced scan in that the image is displayed on a screen by
scanning each line (or row of pixels) in a sequential order rather than an alternate order.
Therefore, in progressive scan, the image lines are scanned in numerical order (1, 2, 3)
down the screen from top to bottom, instead of in an alternate order (lines or rows 1, 3, 5,
etc. followed by lines or rows 2, 4, 6). By progressively scanning the image onto a
screen every 60th of a second rather than "interlacing" alternate lines every 30th of a
second.