COMPARATORS

A common arithmetic requirement is to compare two numbers, producing an indication if they are equal or if one is larger than the other. The Exclusive-OR produces a 1 if the two inputs are unequal and a 0, otherwise. Multibit numbers are unequal if any of the input pairs are unequal.  The output of the NOR is 1 if he number are equal. We accomplished the same thing with Exclusive- NORs and an AND gate.

4-BIT COMPARATORS

EXCLUSIVE OR

EXCLUSIVE NOR

These comparators can be extended to any number of bits.

          To build a 4 bit comparator that will indicate greater than and less than, as well as equal to, we recognize that starting at the most significant bit,

This can, of course, be exerted to any size, or 4 bit comparator can be cascaded, passing on the tree signals, greater then, less than, and equal to.

A TYPICAL  BIT OF A COMPARATOR

By: Dinah Rose Y Galiza