Multiplexer in Digital Logic : Practice MCQ Questions & Answers with Explanations

Explanation: Demultiplexer (Demux) Definition: A demultiplexer (Demux) is a combinational logic circuit that takes a single input signal and channels it into one of several output lines. The specific output line that is selected for the input signal is determined by a set of select lines. It essentially performs the reverse operation of a multiplexer (Mux).

Key Points Frequency-division multiplexing: In telecommunications, frequency-division multiplexing (FDM) is a technique by which the total bandwidth available in a communication medium is divided into a series of non-overlapping frequency bands, each of which is used to carry a separate signal. For example, the coaxial cable used by cable television systems has a bandwidth of about 1000 MHz, but the passband of each television channel is only 6 MHz wide, so there is room for many channels on the cable. Time-division multiplexing: Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fraction of time in an alternating pattern.

Key Points The number of multiplexers required to construct the bus is equal ton, where n is thenumber of bits in each register. The size of each multiplexer must bek: 1 since it multiplexes k data lines, where k is the number of registers. Therefore If there are 8 registers of 16 bits each, then we need 16 multiplexers, each of which is an 8: 1 multiplexer to create the 16-bit data bus.