When tested on a bench, a product generally has the optimal test environment, with short and direct connections to the stimulus and measurement devices. But in production, the interface between a device under test (DUT) and the test instruments will likely include a network of cabling, a signal distribution or switching subsystem, a connector panel, and device-specific adapters.

All of these components do nothing to enhance the pristine signals that were – during product development – passed back and forth directly between the instruments and product on the bench. Instead, they contribute opportunities for signal degradation. In essence, all of the cabling, interfacing and switching should now be considered as an extension of the test instrument and must be allowed for when assessing the instrument’s capabilities.

This white paper will explore the issues in more depth, focusing on how path resistance, line capacitance and insertion loss affect test results and what can be done to minimize their impact.