Removal of time-varying errors in network analyser measurements: system design

Abstract

A new approach to network-analyser measurements has been developed, which uses a dynamic-error suppression technique to remove time-varying component-drift errors (such as amplifier- and filter-response changes) and physical-device errors (such as response changes due to cable flexure). This dynamic-error suppression technique is combined with a conventional static-error suppression technique, such as ‘short/open/load/thru’ (SOLT) or ‘thru/reflection/line’ (TRL), to remove all types of errors. This procedure is referred to as the accurate real-time total-error-suppression technique (ARTTEST). Frequency-offsetting mixers are used to produce the normalisation signals that are required for the dynamic-error suppression. The ARTTEST method allows for the simultaneous measurement of data and normalisation signals that reside at unique, but closely spaced frequencies. These simultaneous normalisation signals are used to greatly improve the measurement accuracy of the system. The ARTTEST method is applicable to a wide variety of measurement problems where high-accuracy results are required. The application of this method to a network-analyser application is demonstrated.