# INTERMITTENT FAULT DETECTION (IFD) EFFECTIVENESS

E = SC^2

E is the Effectiveness that Intermittent Fault Detection technology (IFD) through IFDIS & Voyager provides in detecting intermittent faults versus any other comparable piece of test equipment (measured in a ratio :1)

S is the single circuit intermittence detection speed advantage that IFD has over the single circuit intermittent detection speed capability of any comparable testing technology - IFD sensitivity down to 50ns, 50 nanoseconds, .00000005 seconds.

Example: 100us divided by 50ns = 2000:1 or 100ms divided by 50ns = 2,000,000:1

C, the number of circuits under test, is squared due to the fact that IFD is simultaneously testing all of the circuits, all of the time.  As the conventional tester moves on to test a new circuit one at a time, the IFD continues to test all connected circuits continuously.  Intermittence by its very definition is random in time, place, amplitude and duration. Therefore, the detection of intermittence is a condition of probabilities and the ability to detect it is measured in test-coverage.

Example: 3 by 3 matrix of circuits - 9 total circuits or wires to be tested

Conventional scanning test equipment, while connected to all the circuits, only measures one circuit at a time. While this technology measures test point one (TP1) for one second, IFD all-lines, all-the-time technology, simultaneously and continuously monitors all nine of the circuits or wires for nine total seconds of intermittence test coverage. Conventional equipment then moves on serially to scan TP2, also for one second. IFD again monitors all nine circuits for another second, giving you nine more seconds of intermittence test coverage. Conventional equipment then moves on to TP3 for one-second, the IFD again tests all nine circuits for that same one second.  When conventional testers have finally completed testing each of the nine circuits for just one second each (nine seconds total), the IFD has simultaneously monitored all nine circuits for nine seconds each, (9 x 9) or 81 total seconds.

Result:

Using the E = SC^2 formula of test coverage or probability effeciency of IFD technology, it is obvious why other ATE technologies do not detect and isolate elusive intermittent faults that are random in time, place, amplitude, and duration.

Consider the industry average continuity tester that tests at the rate of 3,500 test points per minute.  The single-circuit intermittent discontinuity detection speed could then be computed to be approximately 17ms (.017 seconds) (60/3500).

If you are serially testing one wire or circuit at a time, then the IFD at 50ns (nanoseconds) is 340,000 times more sensitive at detecting intermittence on a single circuit.

S = .017/.00000005 = 340,000 times more likely to detect NFF intermittence on a single circuit

Example: 100-circuit chassis or 100 wire harness cable using the formula E=SC^2:

E = 340,000 x 100^2 = 3,400,000,000

The IFD is 3.4 billion times more effective than the scanning continuity tester for detecting intermittent/NFF at 50ns on a 100-circuit chassis or cable

Example: 1,200 test point Modular Low Power Radio Frequency (MLPRF) LRU for the AN/APG-68 Radar in the F-16

E = 340,000 x 1,200^2 = 489,600,000,000

IFD is almost 490 billion times more effective than the scanning continuity tester for detecting intermittent/NFF at 50ns on the 1,200-circuit MLPRF chassis

*IFD saved \$62 million for the USAF with MLPRF via IFDIS

These demonstrated advantages in detection probability are why IFD technology through IFDIS and Voyager is solving the intermittent/NFF problem.

Intermittent fault detection specifications measured using Hewlett-Packard 8111A Pulse/Function Generato