US 3,938,087 A · High speed binary comparator

Abstract

A comparator circuit compares the relative magnitudes of two binary numbers. Each of the binary numbers is fed in parallel through a plurality of two-bit comparator modules corresponding to the number of two-bit pairs in the largest binary number. The binary numbers are compared order by order and simultaneously to determine one or more of five relationships between the numbers. For binary numbers greater than two bits in length, the two-bit comparator module is utilized as the basic building block and an additional level of logic circuitry is required in order to obtain an output identifying one of the relationships. Since the two-bit modules may be used interchangeably and since the relative magnitude of any two-bit grouping is generated simultaneously, the comparator circuit provides for a fast and efficient identification of relationships between two binary numbers.

Claims23

Dependent claims

A binary comparator for determining a plurality of relationships between a first and a second binary number, each of said binary numbers having two bits, said comparator comprising:

first comparing means having a plurality of inputs from bits of said first binary number and a corresponding plurality of inputs from complements of bits of said second binary number, said first comparing means providing a first signal indicating a first relationship between said binary numbers;
second comparing means having a plurality of inputs from bits of said second binary number and a corresponding plurality of inputs from complements of bits of said first binary number, said second comparing means providing a second signal indicating a second relationship between said binary numbers;
third comparing means having a plurality of inputs from bits of said first and said second numbers and from complements of bits of said first and said second numbers providing an intermediate signal, said third comparing means further having first inverting means responsive to said intermediate signal providing a third signal indicating a third relationship between said binary numbers;
and
output means coupled to each of said comparing means for transferring each of said indicating signals.

2 more elements

A two-bit binary comparator for determining a plurality of relationships between a first and a second binary number, each number having two bits, said comparator comprising:

first comparing means having a plurality of inputs from bits of said first binary number and a corresponding plurality of inputs from complements of bits of said second binary number, said first comparing means providing a first signal indicating a first relationship between said binary numbers;
second comparing means having a plurality of inputs from bits of said second binary number and a corresponding plurality of inputs from complements of bits of said first binary number, said second comparing means providing a second signal indicating a second relationship between said binary numbers;
third comparing means having a logical NAND gate coupled to receive said first signal and said second signal for providing a third signal indicating a third relationship between said binary numbers;
and
output means coupled to each of said comparing means for transferring each of said indicating signals.

2 more elements

A two-bit binary comparator circuit for determining one of five relationships between a first and a second binary number, each number having two bits, said comparator comprising:

first comparing means including:
a first AND gate having as inputs the least significant order of said first binary number and the complements of the most and least significant orders of said second binary number;
a second AND gate having as inputs the most and the least significant order of said first binary number and the complement of the least significant order of said second binary number;
and
a third AND gate having as inputs the most significant order of said first binary number and the complement of the most significant order of said second binary number;
said first comparing means providing a first signal indicating the relationship that said first binary number is greater than said second binary number;
second comparing means including:
a first AND gate having as inputs the least significant order of said second binary number and complements of the most and least significant orders of said first binary number;
a second AND gate having as inputs the most and least significant orders of said second binary number and the complement of the least significant order of said first binary number;
and
a third AND gate having as inputs the most significant order of said second binary number and the complement of the most significant order of said first binary number;
said second comparing means providing a signal indicating the relationship that said first binary number is less than said second binary number;
third comparing means including:
a first AND gate having as inputs the most significant order of said first binary number and the complement of the most significant order of said second binary number;
a second AND gate having as inputs the complement of the most significant order of said first binary number and the most significant order of said second binary number;
a third AND gate having as inputs the least significant order of said first binary number and the complement of the least significant order of said second binary number;
and
a fourth AND gate having as inputs the complement of the least significant order of said first binary number and the least significant order of said second binary number;
said AND gates connected via an inverter to provide a third signal indicating the relationship that said first binary number is equal to said second binary number;
first inverting means responsive to said first signal for providing a fourth signal indicating the relationship that said first binary number is less than or equal to said second binary number;
second inverting means responsive to said second signal for providing a fifth signal indicating the relationship that said first binary number is greater than or equal to said second binary number;
and
output means coupled to each of said comparing means and inverting means for transferring each of said signals.

20 more elements

A binary comparator for determining a plurality of relationships between a pair of binary numbers, each of said pair having an ordered length of n-bits, where n is a positive integer, said comparator comprising:

first circuitry means including a plurality of comparator modules connected in parallel, each of said modules comparing like orders of two-bits from each of said pair of binary numbers, and providing a plurality of signals each corresponding to one of said plurality of relationships between said pair of binary numbers, and
second circuitry means including a plurality of logic gates coupled to said modules, each gate coupled to receive a signal from at least one module for providing a set of output signals corresponding to the plurality of relationships between the pair of binary numbers.

Dependencies are inferred from the claim text.

High speed binary comparator

Life of this patent

High speed binary comparator

Life of this patent

Abstract

Claims23