- A circuit, device, or program which converts that which has been encoded back into its original form.
- In a TV receiver, a circuit or device which transforms the color-difference signals into separate red, green, and blue signals. Also called color decoder, or matrix (4).
- A circuit or device which produces one or more outputs, based on the combination of its input signals.
- A circuit which responds to a given coded signal, while rejecting all others.
- noun a device for unscrambling satellite signals using a decoder card, obtained by paying a subscription