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New Tuner Offers Diversity in Mobile DTV Apps

While it won't be of much use in countries using ATSC for DTV transmission, MaxLinear's new integrated tuner/demodulator, with dual RF inputs and a diversity combiner, should be of interest to both Japan and the South American countries using ISDB-T or similar modulation for DTV transmissions.

The MaxLinear announcement notes that most mobile TV designs have an external whip antenna to improve reception in dense urban areas, but such antennas are expensive, break easily and prevent waterproofing of the handset.

MaxLinear says that such antennas may no longer be necessary.

Their MxL751SM tuner features "dual RF inputs, a diversity combiner, and 1-Seg demodulator," and was designed with sufficient sensitivity to meet the challenges of mobile reception.

"These portable designs can achieve improved reception using less sensitive and more cost-effective dual internal antennas, which reduces system costs and failure rates," the company said. "Dynamic switching between diversity and single channel modes is built into the device and all channel filtering is integrated along with providing digital carrier and timing recovery."

I have not heard much about diversity reception of ATSC legacy or ATSC mobile DTV signals. It seems that diversity reception should help, if the two antennas can be sufficiently isolated. As interest in ATSC mobile DTV grows, perhaps MaxLinear will offer a device that will work with the U.S. standard.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.