What is the Test Accuracy Ratio (TAR) used for TMDE verification?

What is the Test Accuracy Ratio (TAR) used for TMDE verification?

• A. 2 to 1
• B. 3 to 1
• C. 4 to 1
• D. 5 to 1

Answer: (C)

TAR is the ratio that governs how accurate the reference standard must be compared to the device under test during TMDE verification. In practice, a TAR of four to one means the reference standard is four times more accurate than the TMDE being verified. This setup ensures the standard’s own uncertainty doesn’t mask the TMDE’s true performance, so any out-of-spec conditions in the TMDE are detectable. Four to one is a common, practical requirement that provides reliable verification without making the process overly stringent.

TAR is the ratio that governs how accurate the reference standard must be compared to the device under test during TMDE verification. In practice, a TAR of four to one means the reference standard is four times more accurate than the TMDE being verified. This setup ensures the standard’s own uncertainty doesn’t mask the TMDE’s true performance, so any out-of-spec conditions in the TMDE are detectable. Four to one is a common, practical requirement that provides reliable verification without making the process overly stringent.