What is DTV Technology - Brief Introduction

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What is DTV Technology?
A Brief Introduction

What is DTV?

The standard for broadcasting picture and sound using digital signals, DTV allows for dramatic improvements in both picture and sound quality versus conventional NTSC analog programming. DTV programming can be delivered in two basic formats: standard analog definition (SDTV) or high definition (HDTV).

DTV Format Comparison
Transmission Type	Analog	Digital	Digital	Digital	Digital
	NTSC	Standard Definition	Standard Definition	High Definition	High Definition
Maximum Resolution	480i	480i	480p	720p	1080i
Aspect Ratio	4:3	4:3	4:3 or 16:9	16:9	16:9
Channel Capacity	1	5-6	5-6	1-2	1
Description	Standard TV as we know it today	Good Picture and Sound —DVD or DBS Quality	Better, depending on source; can be outstanding	Best Possible	Best Possible

The highest form of digital television, delivering up to 1,080 scan lines, HDTV produces images that go beyond anything you've ever seen in a home environment. SDTV, or Standard Definition Television, is also a dramatic improvement over today's TV, with the added benefit of allowing stations to broadcast multiple programs within the same bandwidth as an HDTV signal.

DTV Format Detail
ScanLines		Scan Rate	Pixelization	Frame Rate	Aspect Ratio	Formats
SDTV	525 total 480 active	15.75 kHz (60i)	480 x 640	24p, 30p, 60p or 60i fps	4:3	4
SDTV	525 total 480 active	31.5 kHz (60p)	480 x 704	24p, 30p, 60p or 60i fps	4:3 or 16:9	8(4x2)
HDTV	750 total 720 active	45 kHz (60p)	720 x 1080	24p, 30p, 60p	16:9	3
HDTV	1125 total 1080 active	33.75 kHz (60i)	1080 x 1920	24p, 30p, 60i	16:9	3

Adopted DTV formats also include both interlaced and progressive broadcast and display methods.

Interlaced Scanning: The frame/picture is made up of two fields —consisting of 525 lines (480 viewable) or 1125 lines (1080 viewable)

All odd numbered lines are scanned on the screen in 1/60th of a second	All even numbered lines are scanned on the screen in 1/60th of a second	This presents an entire picture in 1/30th of a second

Progressive Scanning : The frame/picture is made up of one field —consisting of 525 lines (480 viewable) or 765 lines (720 viewable)

All horizontal lines are scanned in succession in a single pass	This presents an entire picture in 1/60th of a second (twice as fast as interlaced)

Where is DTV programming?
Right now, a little over 50% of American homes have access to digital television through the four major networks. By 2002, 100% of all commercial stations will offer digital programming. And according to FCC mandate, all U.S. television stations must begin digital broadcasting by 2003, and be exclusively digital by 2006. It's time you went digital. It's in your future.

DTV Broadcast Timeline
1999	2000	2001	2002
Top 4 Networks and Top 10 Markets by May 1 (30% households)			All Commercial Stations by May 1 (100% households)
Top 4 Networks and Top 30 Markets by November 1 (53% households)
2003	2004	2005	2006
All PBS by May 1	75% Simulcast by April 3	100% Simulcast by April 3	All Stations 100% Digital
50% Content Simulcast			Return Analog Spectrum