Sony KV-32XBR400 Training Manual page 23

High Definition Video Input
The Video 5 and 6 inputs can be standard or high definition format sig-
nals. The MID circuit distinguishes the video format by their horizontal
frequencies:
Video 5 or Video 6 Input Formats
480i
480p (4:3 aspect ratio)
480p (16:9 aspect ratio)
1080i (16:9 aspect ratio)
480p Picture Process
A high-resolution 480p-video format is detected by its horizontal frequency
and selected by the MID circuit for video processing. The resultant pic-
ture appearance will depend upon whether the video format of the input
signal is a 4:3 or 16:9 aspect ratio.
4:3 aspect ratio - The MID circuit processes a 480p, 4:3 picture the same
as the 4:3 NTSC picture. The MID circuit adds 60 blank lines to the sig-
nals. The picture is normally overscanned so the 60 blank lines are not
seen.
480p
MID
4:3 pix
Circuitry
Adds 60
blank lines
16:9 aspect ratio - The MID circuit does have to add 60 lines to the 480p,
16:9 picture when the horizontal frequency is changed. When this 16:9
picture is placed on a 4:3 screen, the picture is too tall (screen width was
reduced).
To maintain the aspect ratio of the picture, the vertical size must be manu-
ally reduced so the picture looks normal on the TV's 4:3 screen.
MID
480p
Circuitry
16:9 pix
Horizontal Frequency
15.734kHz
31.50kHz
31.50kHz
33.75kHz
540p
Vert size
increased
540p 540p
Vertical
4 : 3
size
Pix Tube
reduced
19
1080i Picture Process
The 1080i-video format is a high-resolution picture with a 16:9 aspect
ratio at a 33.75kHz horizontal frequency. The 1080i picture actually has
540 lines/scan (half 1080). Although 540 lines would fill this picture tube
vertically, the picture tube is the wrong aspect ratio. The 16:9 picture is
the correct width on the TV, but is too tall because it is displayed on a 4:3
picture tube. To compensate, the vertical size is automatically reduced
when a 33.75kHz input signal is detected. The final 1080i picture is a
"letterbox" on the KV32XBR400:
Aspect Ratio Detection
The picture's aspect ratio is always 4:3 for a standard 480i input and 16:9
for a 1080I input. Unfortunately a 480p signal can be in either aspect ratio
so the TV must be adjusted manually. The MID circuit monitors the hori-
480 lines
zontal frequency of the input signal when video 5 or 6 is selected. If the H.
input frequency is 15.734kHz or 31.5kHz, blank lines are added and the
picture is normally over-scanned vertically for a 4:3 picture. If the H. input
frequency is 33.75kHz, IC201's (A board) vertical oscillator signal is am-
plitude reduced to maintain the correct aspect ratio for a 1080i, 16:9 pic-
ture on a 4:3 picture tube. Vertical reduction must be manually selected
from the user's setup menu when a 480p 16:9 signal is input.
Picture Compensation using Horizontal Frequency
Resolution
480i
480p
480p
1080i
High Definition 1080i
picture on the 4:3
aspect ratio
KV32XBR400 TV
16 : 9 ENHANCED (VERT REDUCTION)
Aspect Horiz Freq Vertical
Ratio Compensation
4:3 15.734kHz Normal Overscan
4:3 31.50kHz Normal Overscan
16:9 31.50kHz Manual Reduction
16:9 33.75kHz Automatic Reduction No
Lines
added
Yes
Yes
Yes