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EETE FEBRUARY 2013

Testing HDMI and MHL successfully By Harald Gsoedl Today’s set-top boxes, tablet PCs and smartphones are equipped with analog or digital video interfaces such as the high-definition multimedia interface (HDMI) and the mobile high-definition link (MHL). Manufacturers test these interfaces at different stages in the value chain to verify their functionality and compliance with standards and thus ensure that they operate flawlessly when they reach consumers. Besides pure interoperability tests, manufacturers are also conducting an increasing number of application tests to see how equipment performs under realistic conditions. The high-definition multimedia interface When HDMI technology was first introduced in 2002, it triggered a paradigm shift within the consumer electronics industry. For the first time, equipment manufacturers and content providers alike embraced a digital video and audio interface standard. Since 2002, more than a billion electronic devices equipped with HDMI have been manufactured. Prior to the introduction of HDMI, consumer electronics equipment typically used analog interfaces to transmit video content, in spite of the known shortcomings compared to digital interfaces. The main reason behind the reluctance among content providers such as Hollywood studios to make the transition from analog to digital was that digital versatile discs (DVDs) or digital video broadcasting (DVB) could potentially allow lossless duplication of content by pirates, directly over external ports. HDMI succeeded in eliminating these concerns. This is because HDMI uses a special encryption mechanism – highbandwidth digital content protection (HDCP) – to secure content against duplication. If this is enabled on the source device (a Blu-rayTM player, for instance), the sink is checked to determine whether it supports HDCP. If it does, the source and sink exchange an encryption key that is used to decrypt the transmitted data. HDMI’s technical design also ensures that video and audio content is transmitted in high quality, with little interference. The data is transferred between devices via three high-speed channels known as transition minimized differential signaling (TMDS) lines. In the most recent version of the interface, these channels are specified to support a bandwidth of up to 3.4 Gbit/s each. The interface also incorporates control lines, as shown in figure 1. Going forward, the focus will be on introducing ultra-definition (UD), which offers resolutions far higher than the 1920 x 1080 pixels currently supported by Full HD. This will take resolutions like 4K x 2K, already widespread in movie theaters and studios for some time now, into people’s living rooms. The demand is there: displays are getting bigger all the time, the first consumer video cameras capable of this kind of resolution are already available, and people are using TVs more and more as an alternative to personal computers. Harald Gsoedl is Product Manager Broadcasting at Rohde & Schwarz – www.rohde-schwarz.com – he can be reached at harald.gsoedl@rohde-schwarz.com International Conference and Exhibition on Integration Issues of Miniaturized Systems – MEMS, NEMS, ICs and Electronic Components Co-organizer: Part of the activities of: Amsterdam, The Netherlands, 13 – 14 March 2013 smartsystemsintegration.com BE PART OF IT! Knowledge exchange Trends and innovations Networking Main conference topics: • 3D-Integration and system packaging •Manufacturing technologies for smart integrated systems •Smart medtech systems and systems for prognostics health management In cooperation with: Register now at smartsystemsintegration.com/registration Further information: +49 711 61946-16 or smart@mesago.com www.electronics-eetimes.com Electronic Engineering Times Europe February 2013 23


EETE FEBRUARY 2013
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