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Truth table of f(x1,x2,x3,x4) function from given two (4-1) multiplexers

Given two (4-1) multiplexers How can I get the truth table of f(x1,x2,x3,x4) function?? enter image description here

Solution

  • A 4-1 multiplexer has the following general truth-table:

    A1  A0  Y
 0   0  I0
 0   1  I1
 1   0  I2
 1   1  I3

    The two control inputs A0 and A1 select which of the four inputs is switched through to the output.

    To get your question solved, start with the left-hand multiplexer and write a truth-table for it. In a second step write the overall truth-table by plugging in the intermediate signal values in the general table shown above.

    The resulting truth-table has four input columns X1, X2, X3, X4. There is one output column Y. Rather than using intermediate truth-tables you could figure out the output value for each of the 16 input combinations.