Haruka's Tech Blog
Injuration: March 2011

Analog vs Digital Terrestrial signals

Countries around the world are switching over from analog to digital signals, with both being provided during the transitional period. Some countries have already shut down the analog signal, while others are in the early/planning stages of it. What I'm discussing here is talking about the over-the-air signals, and therefore, TV content provided over the cable, mobile phone signals, and satellite are not covered in this.

So, what is so great about it? Well, for one thing with digital, you are either going to receive a crystal-clear image or none at all.

But wait: doesn't that mean that those who are already receiving a weak analog signal, even with a signal booster, would not receive at all?

Well, it depends on how far away you are from the transmitting tower. Since digital signals uses less bandwidth (and therefore less power) than analog to get a clear image. you would still receive a very clear image. To put that in perspective, a DVD video movie in 576i (PAL/SECAM) takes up the whole disc, but if stored as data at 720p, compressed, you could store about 12 times more on the same disc and in higher quality. If your signal is poor, but enough to not get a "no signal", you may see odd-looking squares that might be green.

Another thing you may face is receiving the signals. In general, any new TV sold in your area today should be able to receive these signals without any additional hardware. If you somehow have a TV that could only receive a different type of digital signal, or, more likely, an older type of TV that doesn't even know what to do with the digital signals, you may need an external device to help receive the digital signals and send that signal to the TV via the same input you might have used for your console/DVD player.

So, what are they going to do with the former analog frequencies after the shutdown happens?

Well, who knows? Reserved for emergency use, future cellular signals (lower frequencies = larger coverage). One thing's for sure is that if you are used to a grainy analog TV signal and suddenly see the digital HD version, you wouldn't want to turn back. Though, you might not even watch TV for various reasons.

Written by Haruka Takahashi on Saturday, March 5, 2011