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Self Correcting Ring Counter

IP.com Disclosure Number: IPCOM000075963D
Original Publication Date: 1971-Dec-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Houdek, ME: AUTHOR [+3]

Abstract

The circuit diagram shows a 4-bit self-correcting ring counter consisting of four latches and their associated gating. The four latches 21, 22, 23 and 24 are, respectively, formed by gates 2 and 3, 5 and 6, 8 and 9, and 11 and 12. During proper operation, only one latch is set at any one time. A pulse on the "shift pulse" line advances the on-state to the next succeeding latch.

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Self Correcting Ring Counter

The circuit diagram shows a 4-bit self-correcting ring counter consisting of four latches and their associated gating. The four latches 21, 22, 23 and 24 are, respectively, formed by gates 2 and 3, 5 and 6, 8 and 9, and 11 and 12. During proper operation, only one latch is set at any one time. A pulse on the "shift pulse" line advances the on-state to the next succeeding latch.

For an example of the operation, assume that latch 21 is on and the rest of the latches are off. As the "shift pulse" line goes negative, gate 4 becomes conditioned "on", thus setting latch 22. The output of gate 6 is fed back to gate 3, thus resetting latch 21. The output of gate 4 is also fed back to gate 2, holding the gate 2 output up for the duration of "shift pulse" and further, is fed forward to the input of gate 7 to decondition that AND circuit so long as such output is positive. Thus the "on" condition was shifted from latch 21 to latch 22. Another pulse on the "shift pulse" line will shift the "on" state to latch 23.

In order for the circuit to start up correctly when first powered on, additional gating has been added. When latch 24 comes on, gate 12 output resets latches 22 and 23. When latch 23 comes on, gate 9 resets latches 21 and 22. When latch 22 comes on, gate 6 resets latch 21. Thus, only one latch can come on during power up.

Gate 13 detects when latches 21, 22 and 23 are off and sets latch 24, thus insuring that at least one latch will be t...