A diplexer's a passive device that implements frequency domain multiplexing. Two ports (for example, L and H) are multiplexed onto a third port (for example, S). The signals on ports L and H occupy disjoint frequency bands. Consequently, the signals on L and H can coexist on port S without interfering with each other. Typically, the signal on port L will occupy a single low frequency band and the signal on port H will occupy a higher frequency band. In that situation, the diplexer consists of a… (More on Diplexer)