In which of the following adder circuits, the carry look ripple delay is eliminated?

Fast-look-ahead carry circuits found in most 4-bit full-adder circuits which ___________

A

Determine sign and magnitude

B

Reduce propagation delay

C

Add a 1 to complemented inputs

D

Increase ripple delay

The carry propagation delay in 4-bit full-adder circuits ___________

A

Is cumulative for each stage and limits the speed at which arithmetic operations are performed

B

Is normally not a consideration because the delays are usually in the nanosecond range

C

Decreases in direct ratio to the total number of full-adder stages

D

Increases in direct ratio to the total number of full-adder stages but is not a factor in limiting the speed of arithmetic operations

The delay reduced to in the carry look ahead adder is __________

A

5

B

8

C

10

D

2n

The carry look ahead adder is based on the principle of looking at the lower order bits of ________ and ________ if a high order carry is generated.

A

Addend, minuend

B

Minuend, subtrahend

C

Addend, minuend

D

Augend, addend

What is one disadvantage of the ripple-carry adder?

A

The interconnections are more complex

B

More stages are required to a full adder

C

It is slow due to propagation time

D

All of the Mentioned

What is ripple carry adder?

A

The carry output of the lower order stage is connected to the carry input of the next higher order stage

B

The carry input of the lower order stage is connected to the carry output of the next higher order stage

C

The carry output of the higher order stage is connected to the carry input of the next lower order stage

D

The carry input of the higher order stage is connected to the carry output of the lower order stage

For carry skip adder, the minimum total propogation delay can be obtained when m is

A

sqrt(nk1/k2)

B

sqrt(2nk1/k2)

C

sqrt(2k1/nk2)

D

sqrt(nk1k2/2)

What distinguishes the look-ahead-carry adder?

A

It is slower than the ripple-carry adder

B

It is easier to implement logically than a full adder

C

It is faster than a ripple-carry adder

D

It requires advance knowledge of the final answer

Why is a fast-look-ahead carry circuit used in the 7483 4-bit full-adder?

A

To decrease the cost

B

To make it smaller

C

To slow down the circuit

D

To speed up the circuit

The difference between half adder and full adder is __________

A

Half adder has two inputs while full adder has four inputs

B

Half adder has one output while full adder has two outputs

C

Half adder has two inputs while full adder has three inputs

D

All of the Mentioned

In which of the following adder circuits, the carry look ripple delay is eliminated?

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