A component of the decoder in the digital remote control system. It consists of a bistable trigger and a coding switch. Each bistable has two states, "1" and "2". When n bistables are cascaded, there are 2n possible combinations. Each combination is a binary code group. The coding switches are connected according to the binary code group. The purpose of the coding matrix is to convert instructions into electrical signals.

The so-called matrix circuit is a circuit that can linearly add/subtract several input signals in a certain proportion to obtain one or several different output signals. In the video channel of the color TV broadcast end, it is necessary to transform the R, G, B primary color signals into Y, RY, BY signals, and the change relationship is

This operation is a matrix operation, so the circuit that implements the above operation is called a coding matrix circuit.