How TV Phones Work

Mobile TV Reception

Toshiba V401T
Toshiba V401T
Photo courtesy Vodafone K.K.

When it comes to receiving TV signals, you're dealing with a TV tuner, which is a type of radio receiver. There are both analog and digital tuners, and it's the same technology that's in a stationary TV set.

The basic premise underlying a TV tuner is that content providers transmit TV signals in certain radio-frequency bands for certain channels. Just like an AM/FM radio tuner, the TV tuner listens to a specific frequency to pick up the radio waves transmitted to the antenna for a specific channel. It then extracts the video and audio signals from those radio waves.

To turn those signals into a TV show, the tuner sends them to an audio/video (A/V) processor, which decodes and reformats the information so the electronics in the display can create a picture out of it. (See How Television Works, How DTV Works and How Graphics Cards Work for complete information on this process.)

One analog-TV phone on the market is the Toshiba V401T. It picks up the same signals a rabbit-ear TV picks up, meaning watching TV on this phone doesn't cost anything. The V401T has a built-in analog TV tuner and antenna, an A/V processor and a 2.2-inch, 320x240-pixel QVGA display. It can generate 30 frames per second, which is standard TV motion, and you can watch up to one hour of TV on a single battery charge. Phones that receive analog TV typically don't offer as much viewing time as digital receivers partly because it takes more power to digitize the analog signals for the phone's digital display.

Nokia N92 phone Nokia N92 phone
Nokia N92 phone
Photo courtesy © Nokia, 2005

With the Nokia N92, you can watch up to four hours per charge. The N92 is a DVB-H receiver due for release by mid-2006. Under the hood is a TV antenna and DVB-H radio receiver -- essentially a digital TV tuner that listens to the radio bands between 470 and 702 MHz. The phone's audio/video processor displays 30 frames per second on a 2.8-inch QVGA screen with 16 million colors. One of the coolest features of Nokia's DVB-H phone is the swivel screen, which you can adjust for portrait or landscape TV-viewing modes. There's also an "Electronic Service Guide" that displays TV programming, among other things, and you can record up to 30 minutes of TV on the phone for later playback.

Samsung SCH-B250 Samsung SCH-B250
Samsung SCH-B250
Photo courtesy Samsung Electronics

The latest satellite-TV phone on the market is the Samsung SCH-B250 (only in Korea as of March 2006). It has a built-in S-DMB receiver with antenna and a hi-res QVGA screen. The screen is oriented horizontally and swivels for switching between portrait and landscape modes while the phone is still upright. It has a video-out jack for sending S-DMB content to an external display, and you can watch up to three hours of TV on a full charge.

The current availability of mobile-TV handsets is fairly limited because the content-delivery systems aren't deployed on a mass scale. But that's likely to change within the next six to 18 months, and with increased content delivery will come increased functionality on the receiving end.

The Future of Mobile Entertainment

LG V9000 LG V9000
LG V9000
Photo courtesy LG Electronics

In early 2006, LG unveiled the V9000 phone, a T-DMB receiver with the added bonus of virtual surround sound. LG's prototype SB130 is an S-DMB phone that can pause live TV like a DVR, recording up to an hour of programming using its onboard memory. Features like DVR functionality and surround sound point to the possibility that TV-enabled cell phones will become increasingly focused on providing a satisfying viewing experience, instead of just something to look at on the commuter train.

Along this line, as mobile-TV content becomes more readily available, we'll almost definitely see larger screens on TV phones. Some analysts are even predicting multiple phone displays -- one for cell-phone and Web functions and one dedicated to streaming video. If the technology is to gain a real foothold, and if high-end features like HDTV reception are to be viable options, battery life will have to increase. High-end TV phones will also offer advertisers a whole new content platform. Companies are already talking about embedding Web links in mobile-TV programming so users can click their way to a product in the middle of a show. This would probably necessitate the dual-display feature in order to be effective.

Even showing so much promise and industry enthusiasm, mobile TV has some obstacles to overcome both on the device side and the content side. To deliver the types and range of content that consumers really want, mobile-TV providers will have to license programming from the major TV networks. The licensing fees will probably end up raising the cost of any TV subscription service. Content providers will also face digital rights management (DRM) issues in delivering licensed content to users. They'll have to develop DRM schemes that limit what users can do with the copyrighted TV programming that's delivered to their cell phones. And if the uproar surrounding DTV, DVD, CD and MP3 DRM schemes is any indicator, it could get hairy. Still, you never know -- maybe everybody will just get along when it comes to mobile TV.

For more information on TV phones and related topics, check out the links below.

Related HowStuffWorks Articles

More Great Links


  • "3GSM 2006: hands on with LG's DVB-H TV phone." Tech Digest.
  • Baig, Edward C. "Channel surf on your cell phone with MobiTV." Feb. 11, 2004.
  • DVB-H: Global Mobile TV
  • Hesseldahl, Arik. "A Mobile Phone That Tunes In TV." July 29, 2003.
  • "Honey, what's on the cell phone tonight?." ZDNet News. Feb. 6, 2006.
  • Kharif, Olga. "TV Phones Prep for Prime Time." BusinessWeekOnline. Dec. 1, 2004.
  • "Mobile TV." Telecom ABC.
  • MobiTV
  • "MobiTV teams with IPWireless." CNET Feb. 8, 2006.
  • "OFDM Tutorial." WAVE Report.
  • "Orange to Test MBMS-Based Solution in Its UK Unpaired 3G Spectrum." IPWireless.
  • PCMagazine Glossary,1759,1770835,00.asp
  • Qualcomm MediaFLO.
  • "Sanyo's Digital TV Phone." MobileBurn.
  • "Satellite DMB Service." SK Telecon.
  • Sundgot, Jørgen. "TV-enabled LG V9000 swivel phone makes appearance." infoSync World. Feb. 17, 2006.
  • Williams, Martyn. "Hitting the Street With a Satellite TV Phone." Oct. 19, 2005.,aid,123078,00.asp
  • Williams, Martyn. "Samsung Phone Adds TV Reception." June 12, 2003.,aid,111132,00.asp