1. Combining two signals (which can be analog or a digital stream) into one in such a way that they can later be separated. Examples are OFDM; standard FM stereo broadcast (in which left and right are multiplexed onto one baseband signal); standard televi
2. An array of analog switches, usually on a single CMOS chip, that allows one input signal to be routed to any of several output lines, depending on the value of a set of digital control lines.
A multiplexer can also be used in the opposite direction, allowing the array to connect one of several input lines to the output, depending on the control lines.
Several of these can be implemented on one chip to make a multi-channel version.
