One of the things that caught my eye recently was the GNU Radio project:
One of its main ideas is that with a moderately fast PC, you can do AM/FM/etc signal processing in software across a large radio frequency spectrum.
They have a hardware device comparable in scale to the WinRadio here, at about the same price point, about $625 USD for the board and a receiver module:
The board uses USB 2.0, and does the Analog to Digital conversion across the USB bus - ie, DIGITAL SOUND, straight into the PC, to be manipulated however you'd like with software.
Pros and Cons:
- The hardware device is software programmable, and can handle most of the math-intensive processing operations on the board.
- You're not limited by the hardware - if you wanted to add a feature like RDS decoding, just write the software.
- The Gnu Radio software currently only runs under Linux, but there are Windows and Mac ports in process.
- The hardware device does not (yet) support Windows or Mac.. someone would have to write drivers or code.
- Most of the current Gnu Radio software is geared towards basic radio frequency analysis, kind of line oscilloscopes or frequency meters. A TiVo Radio like feature is possible, but someone would have to write it. Same goes for a typical "Car Stereo" type front-end.
- Software signal processing still requires a moderately fast CPU - a Pentium M or Pentium 4 would probably work well, but a lower-end Epia board probably wouldn't do the job.
The thing that really caught my eye was that once you made the investment in the hardware, the rest of the features are software, and can be updated over time.
All the software, schematics, and diagrams are open source.