While sitting in a friend’s car this evening (in motion; we weren’t just sitting there), he was flipping around on the radio trying to find a good song. He finally found one we liked, but it was partway through. He hit a button and the song started anew.:eek:
It turned out that it was actually a cd that he had switched to, and he had just started the song over.
However, that got me thinking. As more and more car stereos are going to be encorporating hard disks or other massive storage for mp3 and other media, how hard would it be to have a recorder built in to the radio that would record what was playing so that, if you changed to a song you liked, you could just rewind and hit the rest?
With, say, a 2 G drive, you should easily be able to store the last 20 minutes (plenty long for even quite a long song or set) of the maybe 100 radio bands you can receive at any given time (FM, every .2 MHz, AM, uh… every 100 KHz?) in 128Kb mp3. And 2 G is pretty small. You could have a bigger drive with other stuff on it too.
The big problem, I think, is the tuner. I have only a dim understanding of the workings of a radio, but I think that you have to actually be tuned in to only one station at a time. To receive and store 100 stations, you’d need 100 tuners. The first thing I thought of was to just have, say, 6, that were set to your favorite stations. But then I wondered?
Is it possible to just capture the entire radio signal at once, digitize it, and store it on the hard disk? Is it reasonable to do so? If you could store the whole signal, then no problem; just go back and tune to what you wanted to hear.
My guess is that it would take significantly more space to store the radio signal. To capture radio at 110 MHz, we need 220 million samples/sec, right?
So, calling electrical engineers: Is this feasible? if not, what’s the limiting factor?