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Search On Range Associative Memory

IP.com Disclosure Number: IPCOM000097348D
Original Publication Date: 1962-Oct-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Anderson, JL: AUTHOR

Abstract

An associative memory is a device which locates desired words in memory by comparing a portion of the word itself with a match value. Association by a range of match values rather than by an exact value has many advantages. For example, in a list of names and ages, names of all persons between ages 35 and 50 can be located by association on the 35...50 age range.

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Search On Range Associative Memory

An associative memory is a device which locates desired words in memory by comparing a portion of the word itself with a match value. Association by a range of match values rather than by an exact value has many advantages. For example, in a list of names and ages, names of all persons between ages 35 and 50 can be located by association on the 35...50 age range.

A binary cell memory, capable of determining for a particular memory word whether a 1 or a 0 value stored in each cell mismatches a 1 or 0 in a match word, performs the select-on-range function by addition of this circuit. The memory cell is interrogated first for a 0 and then for a 1 mismatch. It produces a mismatch signal, if the stored value in the cell disagrees with the match word bit value. Mismatch detection loop 1 carries the mismatch signal.

The signal on detection loop 1 passes transformer 2 and is applied to two amplifier gates 3 and 4. These operate alternately on 0 and 1 interrogations, respectively. If 1 gate 3 is open, the coincident mismatch signal is caused by a 1 in the memory cell during a 0 interrogate. The significance of this mismatch signal during scanning of ordinary binary coded numbers from high to low orders is that the memory word is greater than the match word. Similarly, the output of 0 gate 4 is fed to high latch 5. High latch 5 is cross-coupled to low latch 6 so that the first mismatch signal controls the final high-low setting.

Logic 7... 11 responds to the outputs of high latch 5 and low latch 6 according to the scheme pro...