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利用者:Y717/わーくすぺーす/その2

WirelessHD とは、家電製品向けに無線を用いた Hidh Definition 信号伝送の為の新しいデジタルインターフェースを定めた、業界主導による仕様。コンソーシアムには、仕様を定めた主要メンバーであるBroadcom、Intel、LG、Panasonic、NEC、Samsung、SiBEAM、Sony、Philips、Toshibaをはじめとして、現在40社以上が加盟している。

2008年1月には仕様が確定している[1]。

テクノロジ

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WirelessHD の仕様は、EHF帯 60 GHz 帯の 7 GHz チャンネルに基づいている。これは、高精細度ビデオとオーディオ、そしてデジタル信号を圧縮 (H.264) または非圧縮のデジタル伝送が可能であり、本質的にワイヤレスなHDMIと同等である。第1世代の実装は 4 Gbit/s のデータ転送レートを記録したが、コア技術は理論上の最大データ転送レートが 25Gbit/s であり（他と比較したとき、HDMI 1.3 では 10.2 Gbit/s、DisplayPort 1.2 では 21.6 Gbit/s の伝送が可能）WirelessHD は


Technology

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First-generation implementation achieves data rates from 4 Gbit/s, but the core technology allows theoretical data rates as high as 25 Gbit/s (compared to 10.2 Gbit/s for HDMI 1.3 and 21.6 Gbit/s for DisplayPort 1.2), permitting WirelessHD to scale to higher resolutions, color depth, and range. The 1.1 version of the specification increases the maximum data rate to 28 Gbit/s, supports common 3D formats, 4K resolution, WPAN data, low-power mode for portable devices, and HDCP 2.0 content protection.

The 60 GHz band usually requires line of sight between transmitter and receiver, and the WirelessHD specification ameliorates this limitation through the use of beam forming at the receiver and transmitter antennas to increase the signal's effective radiated power. The goal range for the first products will be in-room, point-to-point, non line-of-sight (NLOS) at up to 10 meters. The atmospheric absorption of 60 GHz energy by oxygen molecules limits undesired propagation over long distances and helps control intersystem interference and long distance reception, which is a concern to video copyright owners.[2]

The WirelessHD specification has provisions for content encryption via Digital Transmission Content Protection (DTCP) as well as provisions for network management. A standard remote control allows users to control the WirelessHD devices and choose which device will act as the source for the display.

Promoters

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Competition

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  • Wireless Gigabit Alliance (WiGig) promotes a different specification for multi-gigabit wireless communications operating over the same unlicensed 60 GHz spectrum.
  • Wireless Home Digital Interface (WHDI) specification uses 20 or 40 MHz channels the 5 GHz unlicensed band, offering lossless video and achieving equivalent video data rates of up to 1.5 or 3 Gbit/s.
  • Wireless USB enables computers without a video-out port to connect to external monitor or TV via the USB ports.

See also

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References

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  1. ^ http://www.wirelesshd.org/about/
  2. ^ “CES to Showcase Wireless HDTVs”. nytimes.com. http://www.nytimes.com/aponline/technology/AP-Wireless-High-Def.html?ref=technology 2008年1月3日閲覧。  [リンク切れ]
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