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DTV standard challenges mobile TV spec in China

Posted: 18 Sep 2008 ?? ?Print Version ?Bookmark and Share

Keywords:China mobile TV? DTV standard? digital TV?

China's mobile TV market is heating up with a possible competition to the China Multimedia Mobile Broadcasting (CMMB) chips.

Fabless chip company Legend Silicon is rolling out three new digital TV chips based on China's terrestrial DTV broadcast standard called GB20600-2006.

All three chips, essentially terrestrial DTV demodulation ICs integrated with memory and ADCs, are designed for use in everything from fixed TV, STBs to portable devices!to be viewed on a train or a bus!and mobile phones, according to Ben Runyan, VP of marketing at Legend Silicon.

Unlike the U.S. DTV standard ATSC, originally designed only for viewing on a fixed TV at home in mind, China is touting that its GB20600-2006 standard is a terrestrial DTV standard developed for both fixed TV and handheld devices.

The GB20600-2006 standard was formerly known as DMB-T/H (Digital Multimedia Broadcasting Terrestrial/Handheld).

Some observers call China's GB20600 standard "an ultimate compromise" of two competing standards!one developed by Tsinghua University in Beijing and another by Jiaotong University in Shanghai. The new spec is viewed as the co-existence of two separate standards, rather than a single standard integrating both approaches.

Tsinghua's system TDS-OFDM (Time Domain Synchronous OFDM) uses multicarriers just like DVB-T and Japan's ISDB-T. Meanwhile, Jiatong's ADTB-T (Advanced Digital Television Broadcast Terrestrial) is a single carrier vestigial sideband system based on the US 8-VSB standard.

Legend Silicon, with strong ties to Tsinghua University, provided the brains behind TDS-OFDM development.

Legend Silicon noted that the new chips are the company's 8th generation DTV demodulator compliant to China's terrestrial DTV standard.

Limited market players
China, however, has yet to see very many competitors jumping into its market. This is partly explained by the fact that China's analog TV broadcast cut-off date won't arrive until 2015.

Further, Legend Silicon does have a leg up on its competitors because it was the key backer of Tsinghua's system.

The only other serious competitor on the GB20600-2006 compliant digital TV chip market thus far, according to Legend Silicon, is HDIC, a subsidiary of Jiaotong University, which developed the competing ADTB-T system.

Micronas, however, announced just two months ago a family of digital terrestrial demodulators based on GB20600-2006.

Runyan said, "I think competitors are coming. The standard justifies the project and if you are not in it, you won't be able to learn the market." Legend Silicon's plan is, however, "to keep the bar forward so that it's harder for others to catch up," he added.

Alon Ironi, CEO of Siano Mobile Silicon, which makes multi-standards mobile TV chips including one based on the CMMB standard, acknowledged that his company is following GB20600. "It's on the roadmap," said Ironi, but declined to disclose a timetable.

Ironi, however, also indicated that any DTV chip companies, including Legend Silicon, looking at the Chinese market may feel compelled to jump into the CMMB fray, "because the CMMB market's uptake is very fast."

But when asked if the mobile TV market may be sewn up by CMMB chips before the GB20600-2006 standard catches fire, Legend Silicon's Runyan said he isn't worried.

Runyan stressed, "Mobile TV is a market driven by business models. In contrast, terrestrial digital TV is driven by the government's mandate."

In the long run, Legend Silicon is confident that the GB20600-2006 spec will become a ubiquitous standard for devices of any screen size in China. "CMMB will help educate consumers on mobile TV," he said. "But China is a huge market. There will be a lot of room for a lot of players."

DTV chips
The three chips Legend Silicon has launched include LGS-8G75, LGS-8G77 and LGS-8G78.

According to the company, the LGS-8G75 and LGS-8G77 are the first two members of the LGS-8G70 family, which "support single- and multicarrier broadcasts, integrate ADCs and time de-interleaver memory, and provide correction for silicon tuner IQ imbalance."

Meanwhile, the company claims that the LGS-8G78 is "the world's first GB20600-2006 standard demodulator with diversity functionality."

When two antennas and two tuners are added to a portable device, Legend Silicon's diversity chips used in a pair can pick up even signals that are 37 percent weaker than normal (in 16-QAM mode). Further, in a poor carrier-to-noise-ratio environment, "With diversity, we can handle more than twice the noise!3dB !when operating in 16-QAM mode," said Runyan.

16-QAM is one of the most common modes deployed in China and is defined in the GB20600-2006 standard, according to Legend Silicon.

Both LGS-8G77 and LGS-8G78 are integrated with a USB and secure digital I/O (SDIO) interfaces.

The power consumption of Legend Silicon's new demodulation chips is "sub 400mW," according to Runyan. "When used in a smart phone running on 1,000mA battery, it enables a couple of hours of viewing time," he said.

All the chips are fabricated at Taiwan Semiconductor Manufacturing Co. using a 90nm CMOS process.

The LGS-8G78 with diversity feature is $15 in 10,000 units. The two other demodulation chips ! LGS-8G75 and 8G77 ! are priced at the "mid to low teens," Runyan said.

LGS-8G75 is shipping, while LGS-8G77 and 8G78 are sampling, with a plan for volume production in November this year. These chips will be available for digital TV designs in, in time for China's next February, according to Runyan.

- Junko Yoshida
EE Times

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