Handset tunes in analog TV

Some countries get to have all the fun. The Sharp V402SH cell phone was released for the Personal Digital Cellular network in Japan sporting a built-in analog TV, so that customers can tune in to news or a favorite rerun while waiting for that important call. Oh sure, it has the usual array of bells and whistles to complement the phone. But it's the TV feature that makes it different, and it's the mixed-signal silicon integration that brings it all together in such a small package.

Sharp is not the first company to bring TV to the phone, however. Back in 1999, Samsung introduced the SCH-M220, featuring the first analog TV tuner to be combined into a cellular handset. But technology advances have brought significant integration to the TV tuner technologies available to gadget makers today.

While space limitations preclude showing all the V402SH's internals, the lower half of the flip phone contains a main board and a second daughtercard to the main board for TV reception. The upper part of the handset houses both an LCD and its accompanying pc board.

The main board supports all the communications functions, with a baseband chip set from Toshiba, RF transceiver from Fujitsu, RF frequency synthesizer from National Semiconductor and RF transmit-receive switch from Sony. A stacked memory device from Sharp delivers a mix of three memory technologies in four separate chips, all in a single package to save serious real estate.

As with virtually every cell phone, power management looms large. A Rohm-manufactured chip tackles system-level orchestration of power delivery, while local regulators address fine-grained power needs.

More goodies live in the tightly packed embedded Sharp camera module, which houses both a charge-coupled-device timing generator and image processor along with the 1.3-megapixel CCD image sensor and lens. Roughly the size of an overgrown sugar cube, the image module produces output that, while certainly lacking compared with today's high-end digital still cameras, begins to take useful images for long-term visual archiving.

The TV system itself is surprisingly well-integrated, requiring only two major chips: a silicon TV tuner by Sony and a sound/video signal-processing chip by Renesas. Output from the TV subsystem is sent to a second board resident in the upper half of the flip-style handset, where it connects to an NTSC/PAL video decoder by AKM Semiconductor (AK8855). Once decoded by the AKM part, the TV broadcast signals are provided as input to a Sharp LCD controller device (marked IXA008 and possibly corresponding to Sharp's catalog part LR38866), which directly drives the LCD.

In an effort to produce a more comfortable TV-viewing experience, the Sharp phone lets users flip the display around and back over the keypad. The result is a very natural screen orientation, with the hinge-mounted loudspeaker and monitor both directly facing the user. The articulated nature of the swivel-flip upper display enclosure also gives the V402SH a complicated mechanical design.

Although the phone is designed to be used in Japan, there is enough overlap in frequencies to allow us to field-test the TV function in the United States. As with most antenna-based analog TV reception, the picture quality varied, depending on station and antenna orientation. Under optimal circumstances, reception was quite good, with minimal fade or noise.

It's possible that analog TV will be a short-lived technology in mobile handsets, however, given the rise of several digitally broadcast alternatives. Digital terrestrial broadcast and digital satellite-based broadcast are undergoing trials in Europe and South Korea, respectively, and handsets for the Korean satellite TV reception model are said to have recently hit production status.

Power consumption with traditional analog TV reception is also an issue. Our measurements suggested that the charge on the 3.7-volt, 740-milliampere-hour lithium-ion battery used in the V402SH is good for less than two hours of TV time.

David Carey, president of Portelligent (www.teardown.com). The Austin, Texas, company produces teardown reports and related industry research on wireless, mobile and personal electronics