Electronic Design

Single-Chip Receiver Brings Analog And Digital TV To Cell Phones

Do people really want TV on their cell phones? The demand might not be there yet, but manufacturers and carriers are working hard on delivering TV to handsets despite the small screen. Telegent Systems' TLG1100 and TLG1130 single-chip TV receivers should make that happen a lot faster.

There are two methods for bringing TV to cell phones. The first uses the existing cell-phone network to deliver Internet Protocol TV (IPTV). Available now from carriers like Verizon, it consists of short clips and show segments. The second method broadcasts TV directly to the cell phone, bypassing the cell network. It's probably the better format, since it won't burden the networks if cell-phone TV gets popular.

Several companies already are lining up to build broadcast towers. Qualcomm's MediaFLO spinoff is sanctioned by both AT&T and Verizon, while Crown Castle's Modeo is looking for a home. To receive such signals, the cell phone needs a separate TV receiver chip, which several semiconductor companies currently offer.

Unlike those chips, the TLG1100 and TLG1130 can receive standard NTSC and PAL analog TV in the 48- to 800-MHz range. So, cell-phone users won't have to wait for the new digital TV services or subscribe to current packages to get TV right now. It also includes a worldwide FM receiver (see the figure).

At the heart of the chip is Telegent's patented SureTrak technology. This DSP method provides superior video reception and increased sensitivity while consuming a total of 250 mW—a necessity for cell phones. SureTrak's multipath and Doppler compensation algorithms help preserve video quality in a fast-moving mobile environment, and they have been proven to be robust at speeds in excess of 265 mph.

The chip works with the cell phone's baseband processor, LCD display, and audio system. Telegent's CTO Sam Sheng says that the company also has some solutions to the need for a long antenna at the lower VHF frequencies, which has plagued handheld TV sales for decades.

The hybrid TLG1130 supports analog and digital TV, including NTSC and PAL as well as the ITU digital video standards DVB-T and DVB-H. Digital Video Broadcast is the digital TV standard in Europe, with the terrestrial (T) version for fixed home TV and the handset (H) version for cell phones and other mobile TV devices. DVB-H is the standard of choice of the Modeo system, which is undergoing tests in New York City but has not yet been widely adopted. Future versions of the Telegent chips are expected to support other video standards such as those in Japan and Korea.

The TLG1100 is already shipping in Asia and being used in Chinese cell phones. The TLG1130 is sampling now with production later this year.

Telegent Systems
www.telegent.com

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