The number of comparators required in a 3-bit comparator type ADC is

It is required to design a binary mod-5 synchronus counter using AB flip-flops such that the output Q₂Q₁Q₀ changes as $$000 \to 001 \to 010$$ ........and so on. The excitation table for the AB flip-flops is given in the table

(a) Write down the state table for the mod-5 counter.
(b)Obtain simplified SOP expressions for the inputs A₂, B₂, A₁, B₁, A₀ and B₀ in terms of Q₂, Q₁, Q and their complements.
(c) Hence, complete the circuit diagram for the mod-5 counter given in the figure using minimum number of 2-input NAND-gate only.

If the input X$$_3$$, X$$_2$$, X$$_1$$, X$$_0$$ to the ROM in figure 2.12 are 8-4-2-1 BCD numbers, then the outpus are Y$$_3$$,Y$$_2$$, Y$$_1$$, Y$$_0$$ are

4-bit 2’s complement representation of a decimal number is 1000. The number is