Accuracy. The extent to which the measured value of a quantity agrees with the true value or accepted value of that quantity. The accuracy of a measurement is its closeness to a reference value.
Autoranging. The capability of an instrument to automatically select the most appropriate range for the measured input.
Calibration. The comparison of a measurement or source of unverified certainty with a measurement of known uncertainty.
Closed Loop Calibration. A fully automated calibration process in which the calibration system reads the unit under test after each applied input, calculates the required calibration adjustment and automatically resets the unit under test.
Frequency. The number of periodic recurrences of an in input in one unit of time.
Full scale. The upper limit of measurement for a given range.
GPIB and IEEE-488. General Purpose Interface Bus, a high speed communications interface commonly used in test equipment. IEEE-488 is the signal protocol used on the GPIB.
Linearity. Degree of conformity to a straight line response. A degree that nominally equal digital steps are equal in magnitude.
Noise. A signal that does not contain useful information.
Over Range. An extension to the full scale over which the unit under test will operate. The unit’s specification is not always guaranteed when operating in this region.
Precision. The degree of agreement among independent measurements of a quantity under specified conditions. The precision of a measurement process is its repeatability. While precision is necessary for accuracy, it does not imply it.
Procedure. A defined series of tests combined to form a series of actions upon a unit under test.
Program. A sequence of commands a computer interprets and causes a system to perform a task.
Prompt. A displayed message that guides the operator to the next step.
Range. Stated upper limits of measurement or value for which a given uncertainty applies.
Resolution. The smallest increment in value that can be detected and displayed by a multimeter.
R.M.S. Abbreviation for Root-Mean-Square. For voltage or current, the value assigned to a level equal to that of a D.C. level producing the same power dissipation through a pure resistance.
Thermal E.M.F. A voltage generated when two dissimilar metals are joined together and heated. This is often a source of error in calibration when using poor quality connections.
Traceability. The ability to relate individual measurement results to legally defined national standards through an unbroken chain of comparisons. Traceability requires evidence produced on a continuing basis, such as calibration records, that the measurement process is producing results for which the total measurement uncertainty relative to national standards is qualified.
Uncertainty. A value, usually centered on the indicated or requested value, within which is a true, accepted or consensus value that is expected to lie within the stated probability or confidence.