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# Frequency Logic

IP.com Disclosure Number: IPCOM000097678D
Original Publication Date: 1961-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 45K

IBM

Ford, NC: AUTHOR

## Abstract

Logical switching operations are performed in a system in which information is represented by waves distinguishable on a frequency basis. Use is made of modulators 10 whose output is proportional to two inputs, filters 12 having a bandpass between frequencies a and b, analogue adders 14, and switching or gating circuits 16. The speed of operation is proportional to the frequencies chosen.

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Frequency Logic

Logical switching operations are performed in a system in which information is represented by waves distinguishable on a frequency basis. Use is made of modulators 10 whose output is proportional to two inputs, filters 12 having a bandpass between frequencies a and b, analogue adders 14, and switching or gating circuits 16. The speed of operation is proportional to the frequencies chosen.

Decimal information ranging from 0... 9 is represented by frequencies ranging from 10.0...10.9 mc. Arithmetic operation is accomplished by first mixing two information inputs representing different decimals in a first line of logic 40. Filtering the sum of these frequencies is effected in a second line of logic 42. Then this sum is mixed with another information input in a third line of logic 44. The difference of these frequencies is utilized to accomplish the desired operation.

Two inputs A1 and B1 are at 40. Each has a frequency range of 10.0...10.9 mc. The sum frequency of the two inputs is then filtered in 42 and applied to another mixer at line 44 along with input C1 which, at this time, is considered to have a range of 10. 0...10.9 mc. The difference of these inputs is derived from 44 and has a range of 9.1...11.8 mc. If this difference frequency has a range of
9.1...9.9 mc, the result is a sum with borrow. If this range is 10.0...10.9 mc, the result is a sum only. If the range is 11.0...11.8 mc, the result is a sum with carry.

To detect the correct result and achieve proper carry or borrow operations, the output from 44 is passed by either a 9.0...9.9 mc filter or an 11.0...11.9 mc filter, connected in parallel, or the output of 44 is co...