2-16 Service Guide
System Verification and Performance Tests 8719ET/20ET/22ET
System Verification 8719ES/20ES/22ES
RF Network Analyzers
General Information
Verification Kit
The kit consists of the following:
• 20 dB and 40 dB attenuator
•25 Ω mismatch airline
•50 Ω airline
• A 3.5 inch disk containing the factory measured verification data and uncertainty limits
for each device in the kit
Measurement Uncertainty
Measurement uncertainty is defined as the sum of the residual systematic (repeatable)
and random (non-repeatable) errors in the measurement system after calibration. The
systematic errors are directivity, source match, load match, reflection and transmission
frequency tracking, and isolation (crosstalk). Random errors include errors due to noise,
drift, connector repeatability, and test cable stability. A complete description of system
errors and how they affect measurements is provided in the analyzer reference guide.
Any measurement result is the vector sum of the actual test device response plus all error
terms. The precise effect of each error term depends on its magnitude and phase
relationship to the actual test device response. When the phase of an error response is not
known, phase is assumed to be worst-case (−180 to +180°). Random errors such as noise
and connector repeatability are generally combined in a root-sum-of-the-squares (RSS)
manner.
Measurement Traceability
To establish a measurement traceability path to a national standard for a network
analyzer system, the overall system performance is verified through the measurement of
devices that have a traceable path. This is accomplished by measuring the devices in an
Agilent verification kit.
The measurement of the devices in the verification kit has a traceable path because the
factory system that measured the devices is calibrated and verified by measuring
standards that have a traceable path to the National Institute of Standards and
Technology (NIST) (see Figure 2-7). This chain of measurements defines how the
verification process brings traceability to the network analyzer system.
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