W129 — Calibrating attenuators using the 9640A RF Reference
The precision, continuously variable attenuator within the 9640A can be used as a reference in the calibration of other attenuators, or in the calibration of gain or loss of other RF components or paths. This application note will concentrate upon the calibration of fixed and switched attenuators; the method for other components or paths would be similar.
The calibration method to be described compares the unknown attenuator with a
nominally equal Reference value within the 9640A and uses the 9640A unique “Offset” capability to determine in a direct readout either a value for the unknown attenuator or its error from nominal value.