Calibration in portable testers

The author discusses the design requirements and tradeoffs related to the calibration of a portable test system. Current and future approaches to the problem are examined, and their applicability to portable systems is discussed. Investigations and solutions to the problems raised are detailed. It is noted that there are currently only two choices for providing calibration standards in portable ATE (automatic test equipment). The first is to build a station-specific calibration module that only verifies a few key measurement points, and the second choice is to make the calibration module a separate piece of external test equipment. In general, making the calibrator a separate piece of equipment is a better approach because overall it provides the most flexibility and better performance. It helps to reduce the size of the test system and gives the user the ability to leave the calibration module behind if system calibration has been done recently and will not be required again until the system returns to where the test system and the calibration module are kept when not deployed