Abstract: Provided is a method and system for diagnosing a test system to determine whether a condition of the test system contributed to an undesirable measurement result. The method includes interrogating a device under test comprising at least one of transmitting an electric signal to energize a device under test by the test system and conducting a passive measurement that does not require the device under test to be energized to be performed to determine if the device under test satisfies a design parameter. The method further includes processing an output signal including at least one of a responsive electric signal transmitted from the device under test in response to being energized and a passive signal corresponding to the passive measurement, and comparing a value of a property of the output signal to a reference value. Responsive to the comparing, the method determines whether the value of the output signal is within an acceptable tolerance of the reference value.

Abstract: A method for controlling a measurement system includes providing a variable bandwidth DC bias loop for biasing a DUT; providing an AC measurement loop for measuring AC parameters of the DUT; disabling the AC measurement loop and selecting a high bandwidth for the DC bias loop when rapid changes to the DC bias are to be made; and selecting a low bandwidth for said DC bias loop and enabling the AC measurement loop when AC measurements of the DUT are to be made.