LG Electronics: Engineering Behind Mobile DTV

After showing its Mobile DTV-enabled handsets at CES, LG Electronics just demonstrated the handsets–and detailed the technology–at a recent conference on Mobile DTV held in Washington D.C. lg-dp570mh by the Advanced Television Systems Committee (ATSC). Wayne Bretl, principal engineer for LG’s Zenith R&D subsidiary, described the technology for the engineers, manufacturers and broadcast TV executives in attendance. Other speakers described technical strategies for local broadcast station implementation of the standard and coordination efforts within the electronics industry.

Bretl focused on describing the “Physical Layer” of the A/153 ATSC Mobile DTV standard, which is compatible with high-definition digital TV broadcasts, noting that Mobile DTV was designed to be easily received while inside moving vehicles. This, said Bretl, is an engineering feat not addressed in the original digital TV standard.

“Our challenge in developing the mobile DTV physical layer was to ensure that the current method of transmitting over-the-air HDTV was not negatively affected by the addition of mobile programming,” Bretl said. “Layered on top of the regular ATSC transmission are entirely new packets of information that augment the signal with additional training sequences, forward error correction, and encoded transmitter and channel data that insures that the receiver will be in sync with the transmitter.”

That includes the ability to receive a solid signal even in a fast-moving train or the backseat of a car, added Bretl, whose technical presentation explained pre-processor and post-processor hardware modules as well as the ATSC Transport Packets in the studio-transmitter link containing mobile DTV data.

Legacy ATSC receivers, from today’s flat-panel HDTVs to those first digital TV receivers shipped ignore the additional mobile DTV information, Bretl explained. New mobile DTV receivers, however, are designed to specifically look for the new data, receive it, decode it, and display it–typically on a handheld device like a new portable DVD player or a prototype cell phone equipped with mobile DTV circuitry.

The first consumer product certified to comply with the new ATSC Mobile DTV Standard is LG’s DPH570MH, a battery-powered DVD player with a 7-inch screen, stereo speakers and an antenna to pickup mobile DTV programs such as those being sent now in the Washington, D.C. market.

The LG Mobile Digital TV is designed so that its display screen can be tilted to the viewer’s preferred viewing angle. When not in use, the clamshell-style screen folds down, making the device to about 9.5 inches by 6.5 inches.

The DP570MH comes equipped to play DVD movie discs and audio CDs, and it can also display .JPG photos and play WMA music files from its USB2.0 connection. It comes with two earphone jacks so that more than one passenger can enjoy mobile DTV shows or movies in the back seat of the car, or on a train. A removable battery powers the device for up to 2.5 hours in TV mode or up to 4.5 hours during DVD playback. Both AC and Auto power adapters are included. The DP570MH Portable Television with integrated DVD player will be available later inn 2010 at a suggested retail price of $249.

Bretl also revealed that in March 2010 LG plans to release its next-generation mobile DTV chip, the LG2161R receiver IC, which is even smaller, consumes less power, supports various interfaces and provides improved performance.

LG mobile DTV chips already can be found in a variety of new products being introduced by various manufacturers, from laptop USB accessory receivers to netbooks with integrated mobile DTV tuners and a range of prototype devices. Bretl said engineers working on the project rose to the challenge of developing a system that could respond to rapidly changing signal ghosting and also improve resistance to signal fading in a mobile environment.

The current rollout of mobile DTV follows rigorous field testing in Chicago, Columbus, Las Vegas, San Francisco, Raleigh, Dallas, Baltimore, Denver, Milwaukee, Atlanta, Seattle, and Washington, D.C. as well as Buenos Aires and Santiago.

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