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Matrix Decoder

IP.com Disclosure Number: IPCOM000084852D
Original Publication Date: 1976-Jan-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Davis, GT: AUTHOR [+2]

Abstract

The figure shows a specific example of a generic decoder which accepts M binary inputs and selects one of N (where N = 2/M/ or less) outputs, according to the combination of input states. The inputs are divided into two separate groups, each of which is decoded separately. If X inputs 13 are put in one group, and Y inputs 15 are put in the second group, then X + Y = the total number of inputs M. Then the total number of possible outputs from these two group decoders is Z = 2/X/ + 2/Y/. From these Z intermediate outputs, an output matrix is formed, having 2/X/ elements in one axis and 2/Y/ elements in the other axis.

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Matrix Decoder

The figure shows a specific example of a generic decoder which accepts M binary inputs and selects one of N (where N = 2/M/ or less) outputs, according to the combination of input states. The inputs are divided into two separate groups, each of which is decoded separately. If X inputs 13 are put in one group, and Y inputs 15 are put in the second group, then X + Y = the total number of inputs M. Then the total number of possible outputs from these two group decoders is Z = 2/X/ + 2/Y/. From these Z intermediate outputs, an output matrix is formed, having 2/X/ elements in one axis and 2/Y/ elements in the other axis.

Group 1 intermediate outputs 17 provide positive base signals to the NPN transistors of the matrix example shown, and the group 2 intermediate outputs 19 gate current sinks 21 to ground. The matrix selects one of N possible output lines, from the two out of Z inputs it detects from the group decoders.

In the specific example of the figure, a one of 16 decode is shown where 4 input lines are separated into 2 groups with 2 inputs each, resulting in a 4 x 4 output matrix selecting one of its 16 outputs from the 2 out of 8 inputs it detects. An extra device 11 may be placed in series with each output to perform a gating function.

The sequence of outputs follows a Grey code progression in this example, but the input group decoders could be rearranged to furnish straight binary or other codes, as the application requires. An advantage of usin...