Wireless connectivity is emerging as a means for dealing with the costs and complexity of hard-wired custom home entertainment installations in the US. HDMI (High-Definition Multimedia Interface) has become a popular means of delivering all-digital audio and video via a single cable in home entertainment systems. HDMI provides an interface between any audio/video source, such as a set-top box, DVD player, or A/V receiver and an audio and/or video monitor, such as a digital TV, over a single cable. HDMI supports standard, enhanced, or high-definition video, plus multi-channel digital audio on a single cable.
In the US, sales of HDMI cables and HDMI-enabled electronics have coincided with explosive growth in the custom-installed home entertainment system market. Custom installation may sound straight forward but even simple sounding tasks such as extending HDMI connectivity across a house or even a living room can be difficult. HDMI cables are not always reliable. Longer cable runs have been known to require HDMI repeater hardware to be implemented somewhere along the run to maintain the strength of the original signal. Also, when dealing with long runs of cable throughout a home there are bound to be places where it is liable to get knocked around or jiggled, potentially causing a disconnection. In the US custom home theater market, an HDMI cable that can pass HD video and 5.1 surround sound audio without losing signal over a distance of 12 meters - the maximum HDMI cable length for most cable manufacturers - is generally considered a quality cable.
Another variable is the design of HDMI cables. While the connectors are standardized, cables can vary by their flexibility/rigidity and flatness/roundness, for example. This is done to allow custom installers to choose the most suitable cable for the customer's home environment, but it potentially raises the above mentioned cable problems.
All of these variables have created demand for new wireless alternatives for extending the reach of HDMI throughout the home.
Wireless HDMI Extenders
Gefen Inc of the US recently announced a wireless HDMI extender. The hardware acts as an audio/video sender and receiver system and uses wireless HDMI based on ultra wideband (UWB) technology from Tzero Technologies of the US. Encoding and compression are achieved with Analog Devices' JPEG 2000 compression technology. According to Analog Devices, the UWB chipset developed by Tzero delivers the lowest error rates and latency to consistently produce the highest quality picture and multi-channel sound.
Gefen's wireless HDMI extender uses Tzero's TZ 7000 wireless UWB chipset. The chipset boasts a packet error rate of 10 (less than one packet error in more than two hours of HD video) and a signal-to-interference ratio of -10dB.
Tzero's chipset provides transmission speeds of up to 480Mbps, the company asserts. The technology is able to carry three or more high-definition video streams across a 20-meter range while running at 100Mbps, allowing for broadcast-quality video. Gefen's wireless HDMI product consists of a transmitter and receiver and integrates the Tzero TZ 7000 chipset and Analog Devices' JPEG2000 compression ICs. On the transmission side, video data is compressed using Analog Devices' ADV202 JPEG2000 video Codec, combined with audio, then packetized and encrypted, and transmitted via the Tzero MAC and PHY chip. The RF chip transmits the data wirelessly to the receiver where the audio/video data with HDMI is decompressed and presented to the display device via the HDMI port.
In November, Avocent Corp of the US unveiled the Emerge MPX1000 HD extender, a wireless HD media extender providing both wired and wireless connectivity. Avocent said the extender provides connectivity for moving high-definition content from one source to multiple destinations incorporating HDMI technology. High resolution computer graphics up to 1280 x 768 resolution, HD video, stereo audio, and control data can be wirelessly transmitted to as many as eight wireless or wired receivers. A key feature is the product's ability to transmit point to multipoint, as US home entertainment installations often involve systems in multiple rooms.
by Michael Thuresson
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