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Testing Digital Counting

IP.com Disclosure Number: IPCOM000082125D
Original Publication Date: 1974-Oct-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Wojtaszek, MR: AUTHOR

Abstract

This device provides a means of validating encoder operation. Each digit of the digital output from an encoder is converted into an independent analog signal. Adjacent pairs of digits are displayed on a variable persistence or storage oscilloscope, in order to detect irregularities in the encoder operation.

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Testing Digital Counting

This device provides a means of validating encoder operation. Each digit of the digital output from an encoder is converted into an independent analog signal. Adjacent pairs of digits are displayed on a variable persistence or storage oscilloscope, in order to detect irregularities in the encoder operation.

The analog signal A representing one digit is fed into the vertical input of the oscilloscope, and the signal B representing the other digit in a pair is fed into the horizontal input of the oscilloscope. The oscilloscope is triggered so that as the digits from the encoder are stepped from 00 to 99, a 10 X 10 matrix of dots is generated on the oscilloscope display. Irregularities in the encoder operation are readily seen as missing, invalid or repetitious dots.

The oscilloscope may also be triggered so that defective operation in which the encoder counts out of order (e.g., 22-23-14-25) can be easily detected. The dots are suppressed while the lines produced by transitions of the "10's" digits are enhanced -- a miscount is observed as a line in the middle of the oscilloscope screen.

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