What is Software Defined Radio (or SDR)? Wikipedia gives a definition...
In short: an SDR is a radio with no IF, Modulator, or Demodulator stages as we generally understand those terms: a receiving RF preamp feeds directly into a (very fast) A-to-D converter, which is connected to a computer DSP/CPU to tune a signal and extract the modulated audio or data; on the transmit side, the CPU and DSP generate the modulation directly, and feed it to an RF power amp.
In the HF and ham world, it has appeared in 2 distinct phases; in use in high end amateur transceivers and receivers, and utilizing a PC as a controller, letting external software define how the SDR is addressed and utilized.
The forum for this wiki can be found here
Please see the following pages for further information;
- SDRs for Amateur Radio Use
- SDRs with HF Coverage
- SDRs that are Wide Banded
- Professional SDRs
- SDR Software Applications
You can find additional reviews and resources here;