Browse Prior Art Database

AC Testing With DC Testers

IP.com Disclosure Number: IPCOM000086662D
Original Publication Date: 1976-Oct-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Scotto, VA: AUTHOR [+2]

Abstract

It has been found that DC testers, which usually have no AC measurement capability, can, through a simple modification, be adapted to provide limited AC time-delay measurements. This is accomplished by using a digital format, which the tester can handle, and by taking advantage of the DC tester's inherent ability to store data.

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AC Testing With DC Testers

It has been found that DC testers, which usually have no AC measurement capability, can, through a simple modification, be adapted to provide limited AC time-delay measurements. This is accomplished by using a digital format, which the tester can handle, and by taking advantage of the DC tester's inherent ability to store data.

In Fig. 1, the non-critical DC inputs are derived from the DC tester 11 and the AC inputs are derived from an external source.

They could be simulated, for example, by high speed pulse generators. The tester, through its controls to multiplexor 13, multiplexor 15 and its DC inputs to the device 17 under test, determines which delay parameters get tested. The various timing relationships to be measured are set by selective control of the multiplexors. The selected input and output parameters are then compared by suitable high-speed circuitry 19, the output of which is returned to the tester and which may, for example, be in a BCD format. Within the tester, the various limit comparisons can be made and the results printed out.

The high speed circuitry 19 (Fig. 2) consists basically of an electronic delay- line chip 21 which receives the input from multiplexor 13. The delay-line chip can be programmed to have various delays. The output from the delay is compared with the output from multiplexor 15 in the comparator circuitry 23. Where matching occurs, an output from the comparator 23 can reset a latch circuit 25, th...