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The High-Definition Multimedia Interface (HDMI) is evolving to be the standard interface for high-definition TVs. This cable provides both video and audio information. Depending on the resolution of the display, the data rates required for an uncompressed HDMI signal can be substantial. The key advantage of 60-GHz is the ability to provide wireless, secure, and uncompressed high-definition video distribution.
Wireless allows the display to be located far from the information source (DVD player, cable box, etc.). This obviates the need for bulky wires from the “picture-frame” display on the wall to the DVD player in the cabinet.
Security is provided at 60-GHz due to the atmospheric and material properties at this frequency. Over long ranges, there is significant signal loss due to oxygen absorption. There is also significant attenuation through walls. These two facts prevent the HDTV signal from leaking into adjacent rooms and residences. This is a definite benefit when it comes to content providers, who desire to limit distribution of the content to whoever paid for it.
Uncompressed signaling retains the image quality on the link, which is of particular concern if “lossy” compression was being considered. Additionally, avoiding compression avoids the need to pay royalties for the compression algorithm.
The data rates for HDMI depend on the resolution of the display and the use of interlacing or progressive scan. For example, 1080i (the “i” stands for interlaced), with a resolution of 1920x1080, and a frame rate of 25 fps, requires ~2.1 Gbps. This can be calculated by multiplying the number of pixels per frame by the frame rate to get the pixel rate. This number is then multiplied by the number of bits per pixel, which we’ll estimate at 40 (Three 10-bit words for the three colors, and one 10-bit word for audio and vertical/horizontal synch. Refer to the HDMI standard for more precise information). Shifting to 1080p progressive-scan doubles the data rate, as the frame rate doubles. A resolution of 720p would require ~1.8Gbps, and yields similar image quality to 1080i.
Wireless allows the display to be located far from the information source (DVD player, cable box, etc.). This obviates the need for bulky wires from the “picture-frame” display on the wall to the DVD player in the cabinet.
Security is provided at 60-GHz due to the atmospheric and material properties at this frequency. Over long ranges, there is significant signal loss due to oxygen absorption. There is also significant attenuation through walls. These two facts prevent the HDTV signal from leaking into adjacent rooms and residences. This is a definite benefit when it comes to content providers, who desire to limit distribution of the content to whoever paid for it.
Uncompressed signaling retains the image quality on the link, which is of particular concern if “lossy” compression was being considered. Additionally, avoiding compression avoids the need to pay royalties for the compression algorithm.
The data rates for HDMI depend on the resolution of the display and the use of interlacing or progressive scan. For example, 1080i (the “i” stands for interlaced), with a resolution of 1920x1080, and a frame rate of 25 fps, requires ~2.1 Gbps. This can be calculated by multiplying the number of pixels per frame by the frame rate to get the pixel rate. This number is then multiplied by the number of bits per pixel, which we’ll estimate at 40 (Three 10-bit words for the three colors, and one 10-bit word for audio and vertical/horizontal synch. Refer to the HDMI standard for more precise information). Shifting to 1080p progressive-scan doubles the data rate, as the frame rate doubles. A resolution of 720p would require ~1.8Gbps, and yields similar image quality to 1080i.