Browse Prior Art Database

Code Converter

IP.com Disclosure Number: IPCOM000091805D
Original Publication Date: 1968-May-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Pine, AM: AUTHOR

Abstract

The decode network includes decoder stages that are normally inactive, but that are supplied power by control logic, when required, to convert B-A-8-4-2-1 input codes to sixty-four discrete output signals. As an example, the input is derived from a tape reader and the output signals directed to operate a typewriter.

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Code Converter

The decode network includes decoder stages that are normally inactive, but that are supplied power by control logic, when required, to convert B-A-8-4-2-1 input codes to sixty-four discrete output signals. As an example, the input is derived from a tape reader and the output signals directed to operate a typewriter.

The network at A includes eight decoder circuits, each like the circuit at B. The latter circuit, which is an available integrated circuit, is controlled by 1-2-4 inputs only, to provide eight discrete outputs on lines 0 and 1...7. The circuit is logically activated by raising the Vcc input. The N input is gated at all times by a +4 volt input since outputs 8 and 9 are not required. The B-A-8, and B-A-8 input lines gate eight And's, each with an associated emitter-follower circuit. The Sync input is low only when activating the network.

The truth table for each decoder circuit at B is as follows: Input 1 H L H L H L H L H L

2 H H L L H H L L H H

4 H H H H L L L L H H

N H H H H H H H H L L

Output 0 1 2 3 4 5 6 7 8 9 H = High or Positive L = Low or near ground.

As an example of the circuit operation at A, assume B-A-8 inputs are low and 1-2-4 inputs are high. And 4 output goes high, when the Sync line drops to gate the Vcc input to decoder circuit 4 which supplies a 0 output to a power amplifier, not shown, to drive the Space-bar solenoid in the typewriter. Assume as another example, the A-B-8-1 inputs are low and the 2-4 inputs are high....