Demultiplexers Questions and Answers for Viva

Answer-1: A demultiplexer is a combinational digital logic circuit that takes a single input signal and routes it to one of several output lines based on the value of a selection input.

Answer-2: The opposite function of a multiplexer is performed by a demultiplexer. While a multiplexer selects one of many inputs to send to a single output, a demultiplexer takes a single input and routes it to one of many outputs.

Answer-3: The common symbols used to represent a demultiplexer in circuit diagrams are a triangle with a circle at its apex, with multiple output lines branching out from it, along with a selection input line.

Answer-4: The primary purpose of a demultiplexer is to take a single input and route it to one of several possible output lines based on the value of the selection input.

Answer-5: A demultiplexer typically has n control lines, where n is the number of output lines. These control lines determine which output line the input signal is routed to.

Answer-6: In a 1-to-4 demultiplexer, with one input and four output lines, the truth table would have two columns: one for the input signal and another for the selection input. The output lines would each correspond to one of the possible combinations of selection input values.

Answer-7: A demultiplexer routes a single input signal to one of several output lines based on a selection input, while a decoder converts an input code into a set of output signals, typically representing the decoded values.

Answer-8: The number of control lines in a demultiplexer is equal to the number of output lines. Each control line corresponds to one output line, determining which output line the input signal is routed to.

Answer-9: The enable input in a demultiplexer controls whether the demultiplexer is active or not. When the enable input is asserted, the demultiplexer operates normally, routing the input signal based on the selection input. When the enable input is deasserted, all output lines are in a disabled state.

Answer-10: Demultiplexers are used in various digital systems for tasks such as data routing, address decoding in memory systems, signal distribution in communication networks, and parallel-to-serial conversion.

Answer-11: A demultiplexer with n control lines can accommodate 2n output lines by using n selection inputs to specify one of the 2n possible output lines for routing the input signal.

Answer-12: The select lines in a demultiplexer determine which output line the input signal will be directed to. By setting the appropriate combination of select lines, you can choose the specific output line to which the input signal is routed.

Answer-13: A demultiplexer typically introduces propagation delay from the input to the selected output, and it has a fan-out capability that specifies the maximum number of inputs it can drive simultaneously.

Answer-14: A 1-to-2 demultiplexer takes a single input and routes it to one of two output lines based on the value of the selection input. The truth table would list the input signal, the selection input, and the corresponding output lines for each combination of input and selection values.

Answer-15: Demultiplexers are used in memory systems for address decoding, where they select specific memory locations based on the address signals provided by the processor.

Answer-16: A demultiplexer can be implemented using basic logic gates such as AND gates and NOT gates. The control lines are used to enable the appropriate gates to direct the input signal to the desired output line.

Answer-17: While a multiplexer selects one of many inputs to send to a single output, a demultiplexer takes a single input and routes it to one of many outputs based on a selection input.

Answer-18: Yes, demultiplexers can be cascaded by connecting the output lines of one demultiplexer to the selection inputs of another demultiplexer. This allows for more complex routing of input signals to multiple output lines.

Answer-19: Demultiplexers can be used in parallel-to-serial conversion by routing data from multiple parallel inputs to a single serial output line based on a clock signal. Each demultiplexer stage selects one of the parallel inputs to serialize the data stream.