Stars Of The Really Small Screen

An interesting feature of the M/H standard is that instead of streaming packets, they’re sent in a burst mode. These packet bursts are stored at the receiver and assembled into a continuous stream, which is sent for viewing. This helps save power in the receiver, because the receiver powers on only when it receives the M/H data packets. The station can control the picture format. The default in this system, though, is 416 by 240.

The transmitter and antenna remain the same. However, mobile reception can be improved if the station switches to an elliptically polarized antenna that changes the vertical and horizontal transmission pattern. This typically increases the vertical pattern, so it requires a boost in transmitter power to compensate for the loss of some horizontal range.

DESIGN CHALLENGES
Putting mobile TV into a cell phone is not so easy. Designers are just beginning to solve some of these new challenges:

• Power consumption: Adding the receiver chip is a key part of the problem. The radio is sophisticated, but the demodulator and baseband processors are complex and usually power-hungry. The new receiver chips will partially mitigate this problem, but not eliminate it. Each new feature on a smart phone increases the power demands on the battery. The overall effect is simply reduced battery life before recharge is necessary. Battery technology isn’t keeping up.
   
• Processing power: Generally, a more powerful processor is necessary to deal with the additional chores related to the screen and the receiver.
   
• The screen: A larger screen is needed for enjoyable viewing, with its attendant power increases.
   
• More memory: Larger memory is essential to handling TV. Flash covers it, but is still expensive.
   
• Software: The operating system must be able to handle multimedia, and the user interface must accommodate the video in a consumer-friendly way.
   
• The antenna: This may constitute the biggest headache for designers. At TV frequencies from 47 to 862 MHz, the size of a quarter wavelength ranges from about 5 ft at the low end to 4 in. at the high end. For effective reception, the antenna is going to be a compromise length to get a range of frequencies, especially on the lower bands used with the ATSCM/ H system. An extendible whip is the preferred antenna, but no one wants that on a cell phone. Packaged antennas are generally too short to be effective, since they are at the higher frequencies. One potential solution is to use the headphone leads as an antenna, like some MP3 players and cell phones with FM radio. An active antenna design may work. So far, the problem persists.
   
• Content: Content designed for the small screen is essential. Granted, some standard TV will work. But for best viewing, the format must be user-friendly. Shorter content will be needed, too. Music videos should be a big hit.

THE SOCIAL IMPACT
Some studies show that there’s little interest from consumers in watching TV on a small screen. Yet actual tests and usage say otherwise. With programs reformatted for the small screen, viewing a show is not bad at all. And most shows will be shorter to accommodate the battery life limitations. This will attract more subscribers than expected.

Furthermore, free OTA TV will be a big hit once the cell phones and other mobile Internet devices (MIDs) become reasonably priced. Most analysts predict mobile TV will be a big winner. Market research firm TeleAnlytics expects the broadcast mobile-TV market to reach $2.8 billion and serve 50 million users in North America by 2013.

Mobile TV will push us to watch even more TV. As it is, many people think we watch TV too much now. It makes you and your kids less social. Kids are already overly preoccupied with computers and video games. Mobile TV is just one more electronic addiction that will shorten our attention span. Of course, free OTA TV will also bring advertisements. And if you think texting while driving is bad, wait until mobile TV is in full swing.