One important application for diodes is recovering information from transmitted signals. This is referred to as:

In radio terminology, extracting the original intelligence (such as voice or data) from a modulated radio frequency signal is known as "detection" or demodulation. Diodes are commonly used in detector circuits for this exact purpose. A diode achieves this by rectifying the incoming alternating current (AC) radio signal, passing only half of the waveform. The remaining signal can then be smoothed out by a capacitor to recover the original audio frequency. The other options serve different roles in electronics. "Conversion" refers to changing a signal's frequency using a mixer, while "biasing" is the process of setting the correct DC operating voltage for a component like a transistor.