Digital Television
Digital TV replaced analog broadcasts with compressed video signals. ATSC (US), DVB (Europe), and ISDB (Japan) standards brought high-definition pictures, multiple channels, interactive services, and eventually internet-connected sets.
Why Digital TV?
Analog TV allocated 6 MHz channels with significant interference and ghosting. Digital TV uses compression (MPEG-2, later H.264/AVC, H.265/HEVC) to pack multiple HD channels into one 6 MHz stream. The result: pristine pictures, no ghosts, and room for data services.
Compression Technologies
- MPEG-2: Original DTV standard, 19.4 Mbps in 6 MHz
- H.264/AVC: Better compression, used for streaming
- H.265/HEVC: 50% more efficient than H.264, for 4K
- VVC/H.266: Next generation, for 8K and HDR
ATSC (US Standard)
The Advanced Television Systems Committee developed the US digital standard:
- 8-VSB: 8-level vestigial sideband modulation
- Data rate: 19.4 Mbps in 6 MHz channel
- Resolution: Up to 1080i or 720p
- ATSC 3.0: IP-based, mobile TV, 4K HDR, immersive audio
DVB (European Standard)
Digital Video Broadcasting became the global standard outside North America:
- DVB-T: Terrestrial (over-the-air), COFDM modulation
- DVB-T2: 30-50% more capacity than DVB-T
- DVB-S/S2: Satellite, used worldwide
- DVB-C: Cable, now DOCSIS competition
The Digital Transition
The US completed its analog shutdown in June 2009. Countries worldwide followed, with analog switch-off completed by 2015 in most developed nations. The digital dividend freed up valuable spectrum for mobile broadband (700 MHz auctions).
Modern TV Features
- HDR: High Dynamic Range (Dolby Vision, HDR10+)
- 4K/8K: Ultra-high definition at 3840×2160
- Wi-Fi: Smart TV apps, streaming services
- HbbTV: Hybrid broadcast broadband TV in Europe