Sony DTV-01, Manual

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1
Introduction
TV Transmission Formats
Standard Definition/High Definition
Picture resolution is commonly measured in pixels or lines. The number
of pixels is the number of black to white brightness changes possible on
the screen first in a horizontal, then in a vertical row (e.g. 960x480). CRT
manufacturing tolerances limits the number of pixels possible. This is a
common resolution specification in a computer monitor CRT.
In a TV broadcast, the studio camera is the limitation to higher resolution.
The picture scanned by the camera is segmented by pixels similar to the
viewer’s CRT. The greater the number of pixels in the horizontal and ver-
tical row, the greater the resolution. This will be the current resolution
limitation as the USA makes the transition toward high definition digital TV.
In a TV transmission, the ability of a signal voltage to quickly change from
low to high and to produce a dark to white transition is comparable to a
pixel. This is not a limitation in the transmission format, but the number of
lines transmitted is and is used as a resolution measurement in transmis-
sions. The number of lines transmitted in the current USA NTSC format is
525. This is considered a standard definition (SD) transmission.
A standard definition (SD) transmission of 525 lines can be transmitted in
the analog or digital mode. A higher definition (HD) transmission can be
transmitted only in the digital (DTV) mode.
¨
SDTV or SD – Standard definition is the current 525 lines of resolution
transmitted, but only 480 of those lines are viewable. SD can be sent
as an NTSC analog or digital (DTV) transmission.
¨
HDTV or HD – A high-definition transmission contains 720 or more
horizontal lines. HD is transmitted only in a digital format.
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DTV – A digital TV transmission refers only to the digital encoding of
the picture signal that may contain either a high (HD) or low (SD) reso-
lution picture. The digital picture is not viewable on an analog TV with-
out a “decoder box”.
Digital Transmission Formats
There are 18 approved digital transmission formats. The first six offer HD
signals in a 16x9 aspect ratio. The remaining 12 formats are SD signals
in progressive (p) or interlaced (i) scan. Although not high resolution, they
offer significant improvements over the NTSC analog signal.
18 Digital Transmission Formats
Resolution
Aspect
Ratio
Frames Resolution
Aspect
Ratio
Frames
1. 1920x1080 16:9 30 i 10. 704x 480 16:9 24 p
2. “ 16:9 30 p 11. “ 4:3 60 p
3. “ 16:9 24 p 12. “ 4:3 30 i
4. 1280x 720 16:9 60 p 13. “ 4:3 30 p
5. “ 16:9 30 p 14. “ 4:3 24 p
6. “ 16:9 24 p 15. 640x 480 4:3 60 p
7. 704x 480 16:9 60 p 16. “ 4:3 30 i
8. “ 16:9 30 i 17. “ 4:3 30 p
9. “ 16:9 30 p 18. “ 4:3 24 p
A standard definition transmission permits space for another digital video
stream to coexist on the same frequency (channel). Consequently a sta-
tion can have more than one program stream on a digital channel. The
maximum number is not known at this time.