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Testing Digital to Analog Converters

IP.com Disclosure Number: IPCOM000052423D
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Beaven, PA: AUTHOR

Abstract

Digital and analog electronic components are frequently mounted on the same card. Testing of such cards has proved to be particularly difficult.

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Testing Digital to Analog Converters

Digital and analog electronic components are frequently mounted on the same card. Testing of such cards has proved to be particularly difficult.

The diagram shows a card 1 having digital logic circuitry 2 and a digital-to- analog converter 3 mounted thereon. Card 1 is connected by a tester interface card 4 to a digital logic tester 5 for simultaneously testing both digital and analog circuits. The logic tester 5 is programmed to generate test programs of digital pulses on a bus 6, through interface card 4 to the normal digital inputs of logic circuitry 2 of the card 1 to be tested.

The normal digital output of logic circuitry 2 is on bus 7. When card 1 is under test, bus 7 is connected through interface card 4 to tester 5. The normal analog output of card 1 is generated by a digital to analog converter 3 from three digital outputs a, b and c of logic circuitry 2, giving 8 different levels of analog signal V(1).

The analog signal V(1) is one of the inputs applied to a comparator 8 in the interface card 4. The comparator 8 receives its other input V(2) from a `good' digital-to-analog converter 9 mounted on interface card 4. The inputs to converter 9 are outputs a, b and c of logic circuitry 2 which pass through logic block 10. e test patterns for the converter 3 which is under test are generated at the same time as the test patterns for logic circuitry 2 by the programmed logic tester 5. Logic tester 5 models the analog converter 3 and the...