Digital comparator

A comparator in digital technology is an electronic circuit that compares two digital values.

Identity comparator

Identity Comparators (English Identity Comparator ) test two bits for equality, which is done with the help of a XNOR gate. For the comparison of two bytes each equal bits are compared with each other, and combines the result to an AND gate.

Magnitude comparator

Magnitude comparators (English Magnitude Comparator ), in addition to the equality test on the relations Bigger and Smaller. In order to carry out the size comparison must be encoded in the same way the two numbers. In addition, the magnitude comparator has to be designed for the code you are using.

N -bit magnitude comparator

An n -bit comparator sizes based on the principle that the difference of the sizes to be compared is formed and the result is checked to 0 <0 > 0. The addition unit based on the binary code of the addition of the two's complement, ie ( B ) is the same as ( ! B 1). With the addition of a number with its inverted number (eg 1001101 0110010 = 1111111 ) are the result all bits 1 If a number is subtracted from itself, (A - A = A ( A 1) = 0, carry =! 1) the result is 0, with carry 1

If A is compared with B, then:

Extension

Comparing bytes have more locations than is given by the comparator module, a plurality of comparators can be interconnected in series or parallel. The parallel solution is here. Many places in bytes with the advantage of a lower latency, resulting in a higher speed results The serial structure is recommended only if doing less comparator blocks must be used.

• Digital technology