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Infrared Testability Enhancement through Power Supply Variation

IP.com Disclosure Number: IPCOM000078935D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Feuer, M: AUTHOR [+2]

Abstract

In any testing situation where the signal-to-noise ratio is very low, it is far easier to detect a regular, time-varying signal than a constant signal. In addition, it is not necessary to calibrate the instrumentation as precisely, nor to guard against slow drifts in the instrumentation or environment, when the object of the measurement is a difference in signal levels rather than the level itself.

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Infrared Testability Enhancement through Power Supply Variation

In any testing situation where the signal-to-noise ratio is very low, it is far easier to detect a regular, time-varying signal than a constant signal. In addition, it is not necessary to calibrate the instrumentation as precisely, nor to guard against slow drifts in the instrumentation or environment, when the object of the measurement is a difference in signal levels rather than the level itself.

Infrared microscopy of integrated logic circuits can often be used to monitor the levels of the outputs of logic blocks, when these levels are distinguished by conducting and nonconducting states of a resistive element. Since the signal-to- noise ratio is typically low in this application, it is proposed:

1) That a sinusoidal component be impressed upon the power-supply voltage, and that the infrared detector be tuned to the same frequency as this added voltage. It is necessary that the added voltage be small enough not to cause a "0" level to be confused with a "1" level.

2) That the power supply be varied over a broader amplitude range when it is not required that all logic levels be maintained.

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