Superheterodyne receiver technology is practically used in every radio today.Basically heterodyning means stepping down (or up) the frequency of the received signal for easy of processing. One extra stage makes the receiver more stable more selective and increases overall quality. It revolves around a few steps:
1. The received RF signal is amplified (optional)
2. The RF signal is mixed with a lower frequency from a local oscillator. This produces 2 separate frequencies mixed in one. The sum and the substact of the rf signal and the local oscillator (f2-f1) and (f2+f1).
3. One of the product frequencies (usually the higher one) is filtered out and only the lower one remains.
4. Once we successfully stepped down the original frequency we can now feed it to the detector and restore it.
