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1. (1pts) What is the Hamming distance between these two bit patterns: 1001 and 0101?
2. (3pts) How far apart must valid code words be to allow Single Error Detection (SED)?
Triple Error Correction (DEC)?
Quadruple (4) Error Correction Quintuple (5) Error Detection (QECQED)?
3. (3pts) Write the equation for the carry out of the 3rd adder cell in an ALU using carry-
lookahead, in terms of Pโs and Gโs.
4. (3pts) What is the difference between the Mealy and Moore models of sequential design?
5. (10pts) We know that a single cell of a ripple carry adder implements the functions
Cout =AB+ACin+BCin
and
Sum =A xor B xor Cin
Assuming you have made a 3-bit ripple carry adder using these cells, what is the worst case
path through the adder? In other words, how long does it take for the answer to be correct
in all cases? (I suggest you draw the circuit in order to make doing this problem easier).
Use the following delay values, and assume all input signals become valid at time 0:
2-input AND: 5 ns 2-input OR: 4 ns 2-input XOR: 8 ns
3-input AND: 6 ns 3-input OR: 7 ns 3-input XOR: 11 ns
