3.1 OBJECTIVE The objective of this experiment is to design a decoder and get information about multiplexer. 3.2 EQUIPMENT LIST - Digital Training set Y-0039, - Logic Gates : 74155 (decoder), 74151 (multiplexer), OR gate, NAND gate, INVERTER 3.3 THEORY Decoder Decoder is the generic name given to any circuit that converts coded signals at the inputs into coded outputs. It is essential in a decoder that the number of outputs is larger than the number of inputs. Figure 3.1 Multiplexer Multiplexers are primarily thought of as "data selectors" because they select one of several inputs to be logically connected to the output, they can also be used to implement Boolean functions. We can implement any Boolean function of x variables using a 2x input MUX. Multiplexers can be used more effectively by using some forms of functional decomposition; meaning we can implement a 4variable function using 8-to-1 MUX by using three of the variables as select inputs and feeding an appropriate function of the fourth variable to the data inputs of the MUX. Consider the following truth table that describes a function of 4 Boolean variables. Figure 3.2 16 inputs for each of the 16 possible combinations of A, B, C, and D