Question

Carry lookahead logic uses the concepts of ___________

(a) Inverting the inputs

(b) Complementing the outputs

(c) Generating and propagating carries

(d) Ripple factor

This question was posed to me in an interview for internship.

I'd like to ask this question from 4-Bit Parallel Adder/Subtractor in chapter Arithmetic Circuits of Digital Circuits

Answer 1

Correct option is (c) Generating and propagating carries

To explain: Look Ahead Carry Adder is a type of digital circuit which reduces the propagation delay. Carry lookahead logic uses the concepts of generating and propagating carries. Although in the context of a carry lookahead adder, it is most natural to think of generating and propagating in the context of binary addition, the concepts can be used more generally than this.