3-22 Keysight N5221A/22A Service GuideTests and AdjustmentsSystem Verification3-— directivity,— source match,— load match,— reflection and transmission frequency tracking, and— isolation (crosstalk).The random errors include:— noise,— drift,— connector repeatability, and— test cable stability.A complete description of system errors and how they affect measurements isprovided in the analyzer’s on-line embedded help.Any measurement result is the vector sum of the actual test device responseplus all error terms. The precise effect of each error term depends on itsmagnitude and phase relationship to the actual test device response. Whenthe phase of an error response is not known, phase is assumed to beworst-case (−180° to +180°). Random errors such as noise and connectorrepeatability are generally combined in a root-sum-of-the-squares (RSS)manner.Measurement TraceabilityTo establish a measurement traceability path to a national standard for anetwork analyzer system, the overall system performance is verified throughthe measurement of devices that have a traceable path. This is accomplishedby measuring the devices in a Keysight verification kit.The measurement of the devices in the verification kit has a traceable pathbecause the factory system that measured the devices is calibrated andverified by measuring standards that have a traceable path to the NationalInstitute of Standards and Technology (NIST) (see Figure 3-9). This chain ofmeasurements defines how the verification process brings traceability to thenetwork analyzer system.
