Final answer:
A 16-bit comparator with 4 bits of lookahead divides inputs into 4-bit blocks, which are then evaluated using comparators. Lookahead logic accelerates the output by prioritizing the results from the more significant blocks over the less significant ones for a faster, efficient comparison.
Step-by-step explanation:
To design a 16-bit comparator with a maximum of 4 bits of lookahead, we need to understand what a comparator does. A comparator takes two binary numbers and determines if one is greater than, less than, or equal to the other. In a digital circuit, this is done using logic gates that compare bits from the least significant bit (LSB) to the most significant bit (MSB).
We can divide the 16-bit inputs into four 4-bit blocks. Each block will have its own 4-bit comparator. The output of each 4-bit comparator will be 'equal', 'greater', or 'less'. Lookahead logic is then used to prioritize the outputs from the more significant blocks over the less significant blocks. This is because if a more significant block has determined that one number is greater than the other, the comparison result for the whole number is determined regardless of the less significant bits.
The lookahead logic works by 'looking ahead' at the result of the more significant blocks before waiting for the propagation of the signals in the lower blocks. It allows the comparator to generate the output faster, as it does not need to wait for the lower blocks if the decision is already made by the higher blocks. This makes the design more efficient in terms of speed.