Picture Formats - Cisco Explorer 4600HD Series User Manual

Picture Formats

What is the Difference Between a Standard-Screen and a Wide-Screen HDTV?
The type of screen your HDTV has (wide screen or standard screen) determines how the set-top displays
programs on the screen. The picture format for an HDTV is a combination of aspect ratio and screen resolution and
is different for standard-screen and wide-screen HDTVs.
What is Aspect Ratio?
An aspect ratio is the ratio of the width to the height of the TV screen. The aspect ratios differ because the
television industry manufactures both standard-screen and wide-screen HDTVs to appeal to consumer viewing
preferences.
What is the Screen Resolution and Scan Rate?
The screen resolution indicates the amount of detail that the picture displays. Resolution is identified by the number
of display lines on the screen. The techniques that an HDTV uses to "paint" the picture on the screen are referred
to as progressive and interlaced.
With the progressive method, the lines are drawn on the screen one at a time in sequential order. The interlaced
method involves refreshing pixels in alternation — first the odd lines and then the even lines.
For advance setup, select the scan modes that your TV can support. Refer to your set-top and HDTV user's guides
to choose the proper scan rates (480i, 480p, 720p, 1080i) for your setup.
For example, a resolution of 1080i indicates that the screen shows 1080 lines in an interlaced display, and 480p
indicates that the screens shows 480 lines in a progressive display.
Notes:
• The screen resolution (1080i, 480p, and so forth) is sometimes referred to as the scan rate.
The terms are interchangeable.
• You can stretch and zoom the displayed picture using the built-in capability of the set-top by pressing the # key
on the remote control.
A standard-screen HDTV has a 4x3 aspect
ratio. The screen is 4 units wide for every 3 units
tall.
4
3
A screen resolution of 480p or 480i fills the screen.
A wide-screen HDTV is one-third wider than a standard-
screen HDTV. The screen is 16 units wide for every 9 units tall.
9
A screen resolution of 720p or 1080i fills the screen.
16
11