Pocket-sized devices capable of receiving digital, terrestrial and satellite broadcasts may soon be a reality if a number of prototypes unveiled on Wednesday in Tokyo reach the market.

The prototype the most likely to be on the shelves first is a receiver shown by Mobile Broadcasting (MBCO). The company launched a co-owned satellite with South Korea's TU Media earlier this year and plans to begin beaming a seven-channel video and 30-channel audio service to subscribers from mid-October this year.

Unlike existing satellite systems which require large dish antennae, the MBCO services uses lower-frequency signals around 2.6GHz, close to those used by third-generation (3G) cellular services, so it can be received using an antenna built into a portable receiver. The prototype unit on display was developed by Toshiba and the maker is expected to be one of several that produces receivers for the commercial service, said Keiko Ando, a spokeswoman for MBCO.

The channel lineup includes a number of non-stop music channels covering several genre, such as Japanese pop charts, club music, 80's music, folk songs, jazz and classical music, radio stations including the BBC World Service, five FM radio stations relayed live from California and some Japanese domestic radio. Video channels include MTV Japan, financial news service Nikkei CNBC and non-stop news service, said Ando.

A similar service is expected to be launched in South Korea by TU Media and for that Samsung has previously shown prototype cellular telephones with embedded satellite receiver. MBCO's Ando said the company doesn't expect its initial line-up to include such telephones.

That doesn't mean that Japanese handset makers and carriers are ignoring digital broadcasting, as a walk around the show floor proved.

Carrier KDDI, which operates Japan's number two cellular network, was showing a prototype reception system for terrestrial digital radio.

The receiver was based on a PDA (personal digital assistant) and can take full advantage of Japan's service, currently still in the trial phase, which transmits data and some video alongside radio channels. The top half of the PDA screen was used to display the video while the bottom half was used to display information related to the current program. The PDA can also connect to the cellular network if data needs to be sent back to the broadcaster.

Sanyo showed two prototype cellular telephones with digital terrestrial TV reception built-in. The phones feature the ability to display the image sideways to make better use of the screen. They are not expected to be available in Japan until at least a year from now, said Sanyo. NEC also used the exhibition to display a prototype handset that can receive digital TV broadcasts but did not disclose any further information regarding its plans.