| 摘要 |
1,036,233. Semi-conductor logic circuits. INTERNATIONAL BUSINESS MACHINES CORPORATION. May 14, 1964 [May 24, 1963], No. 20095/64. Heading H3T. [Also in Division G4] A logical operation is performed by feeding a number of independent representations of each operand to a plurality of threshold devices, each of which produces an output when its inputs comprise more than a minimum number of like representations. Fig. 5 shows a redundant version according to the invention of AND and OR circuitry for evaluating the Boolean function f = ((A+B)C+D)E. Each ring is a threshold device and the number within the ring is the minimum number of inputs which must be ONE for the output of the device to be ONE. Each operand A to E is supplied on three separate leads as shown. Fig. 7 (not shown) shows a redundant version of a NOR latch, the outputs of six threshold devices of threshold 2 (corresponding to OR gates) being taken in inverted form, the inverted outputs from each three of them being fed back to constitute half the inputs of the other three. In a similar way, the outputs of threshold devices corresponding to AND gates may be taken in inverted form to give NAND circuitry. Fig. 8 (not shown) shows a Kirchoff-adder-type transistor threshold device with adjustable base bias (i.e. threshold) for trouble shooting. Threshold circuits utilizing magnetic cores, parametrons, tunnel diodes and relay circuits are also mentioned. |
