The hottest new thing in sound is called HD Radio technology. And what it does for radio is the same thing that HDTV does for TV ? it makes it light years better! In fact, when you listen to HD AM radio, you'll think you're listening to FM. And when you listen to FM, you'll think you're listening to a CD.

What makes this possible?

HD Radio technology works much like traditional analog transmissions (AM and FM are both analog signals).

The difference is that the station broadcasting HD Radio technology transmits an extra digital radio signal, along with its normal analog signal. It can also broadcast a third signal for text data.

Your radio receiver receives the signal ? just as it does an AM or FM signal. If you have a HD Radio receiver, it will decompress and translate the signal and viola! You get bright, clean, near-CD quality sound.

What happens if you don't have an HD Radio technology receiver? It's simple. You hear your normal analog radio? AM or FM.

AM radio has smaller sections of bandwidth than FM radio. This means there is not enough "space" to give AM stations the same near-CD quality as FM stations. But there is enough bandwidth that AM stations will be able to broadcast with the same clarity of signal as one of today's analog FM stations. This performance boost is expected to make AM radio a better alternative to FM than it has been ? to give you more listening choices.

Less vunerable

Digital FM radio is less vulnerable to reception problems. Your HD Radio tuner's digital processors will eliminate all those annoying pops, hisses, fades and static caused by interference.

What happens if you lose the digital signal for some reason? Really nothing. HD Radio technology defaults back to analog mode in much the same way as conventional radios switch from stereo to mono mode when the signal is weak. Then, when the digital signal again becomes available, your HD Radio automatically switches back. What could be simpler?

Go to for more information about HD Radio technology, a partial list of stations already broadcasting in HD and information about HD portable radios, car radios and recievers. Douglas Hanna is webmaster of and a long time writer and producer of radio commercials.