Comparator: An Overview
A comparator is a fundamental building block in digital design that compares two binary numbers. Comparators can be categorized based on their use and functionality.
- Equality Comparator: it compares the two binary numbers to up a true bit or high when all the binary bits are identical and false or low when the bits are not identical.
- Magnitude Comparator: has three functionality, to determine the relationship between the two binary numbers that are being compared. The three functionalities are greater than, less than, and equal to.
Applications of Comparators
- Comparators are used in sorting algorithms to compare and order numbers.
- In signed subtractions, it is necessary to compare the magnitudes to perform the operation.
- Many control systems and processors use comparators to make decisions based on numerical comparisons.
- Extremely helpful in looping statements.
Design: 4-bit Comparator
A 4-bit comparator consists of two inputs each of four bits and three outputs, one for each comparison. Typically, a magnitude comparator is used widely in many digital system applications. Verilog provides three operators for the three-magnitude comparator operations. They are as follows:
- Greater than: (A > B) checks whether A is greater than B.
- Less than: (A < B) checks if A is less than B.
- Equal to: (A = B) checks if both the values are equal.
Verilog Code: 4-bit Comparator
module comparator #(parameter n = 4)(/*AUTOARG*/
// Outputs
gt, lt, et,
// Inputs
a, b
);
input [n-1:0] a, b;
output gt,lt,et;
/*AUTOREG*/
/*AUTOWIRE*/
assign et = (a == b) ? 1'b1 : 1'b0;
assign gt = (a > b) ? 1'b1 : 1'b0;
assign lt = (a < b) ? 1'b1 : 1'b0;
endmodule