This chapter is from the book
This chapter is from the book
This chapter is from the book
How Digital TV Is Different
So a digital television signal is more like computer data than it is like a vinyl record. What does that mean in practical terms?
First, digital television can’t be received on older analog TV tuners. If you try to tune in the new digital channel 7 on your old TV, for example, you’ll find that there’s nothing there. Analog tuners simply aren’t equipped to receive digital signals. You’ll need either a newer TV with a digital tuner or a digital-to-analog converter box connected to your older TV to watch the new digital television broadcasts.
Second, your local TV station’s digital signal is likely broadcast on a different frequency than its analog signal. Although some stations will retain their old channel numbers, others will change channels. And even if the channel number remains the same, the underlying frequency that your tuner receives might differ.
And that channel number won’t be for a single channel anymore. With digital technology, most local stations will broadcast more than one subchannel of programming. Instead of receiving just a single channel 13, for example, you might be able to tune in channels 13.1, 13.2, and 13.3, each with its own individual programming. This will require you to learn new channel lineups and to punch a different (and slightly longer) number into your TV tuner.
In addition, some stations are switching to different transmitter towers for their digital programming. If your local station changes from a tower currently north of you to one that’s more to your east, for example, you might need to reposition your antenna to receive transmissions from the new tower. This may be a minor inconvenience or it could signal major problems—especially if the new transmitting tower is considerably farther away from your house. In any case, be prepared to at least adjust the position of your antenna to receive the new digital signals.
You need to be aware of one final difference. Even though digital signals are clearer than analog signals, they aren’t always perfect. Whereas an older analog signal might fade and get noisy as you move farther away from the transmitting tower, a digital signal won’t fade. It will stay perfect until that point where it’s too weak to continue. At that point, the picture and sound will simply disappear, often without warning. DTV is an all-or-nothing proposition—either you get a great picture or you don’t get any picture at all!