R&S ZVB - Page 517

R&S
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ZVA / R&S
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ZVT GUI Reference
Channel Menu
Operating Manual 1145.1084.12 – 30 502
length offset and loss correction. For maximum accuracy, it is recommendable to place the reference
plane as close as possible towards the outer test fixture connectors using a full n-port calibration. The
fixture compensation is then carried out in a second step, it only has to compensate for the effect of the
test fixture connections.
The following features can further improve the accuracy of the fixture compensation:
 Direct Compensation provides a frequency-dependent transmission factor (instead of a global
electrical length and loss).
 Open and Short causes the analyzer to calculate the correction data from two subsequent
sweeps. The results are averaged in order to compensate for errors due to non-ideal terminations.
The Fixture Compensation dialog provides the following control elements:
 Physical Ports selects the NWA/fixture ports where the analyzer performs a fixture compensation
sweep in order to determine the compensation data.
 Prompt for Each Standard interrupts the fixture compensation process after each fixture
compensation sweep so that you can modify your test setup (e.g. terminate the next measured
port). Disable Prompt for Each Standard to perform all calibration sweeps without interruption.
 Use Measurement Data for selects the type of compensation that the network analyzer calculates
from the acquired compensation data. Auto Length or Auto Length and Loss implies that a global
electrical length offset and loss is determined in analogy to the general offset compensation (see
Auto Length, Auto Length and Loss). With Direct Compensation, a frequency-dependent
transmission factor is calculated.
 The Open, Short, and Open and Short buttons open the Measure Fixture dialog to start the fixture
compensation sweeps for test fixture connections which are terminated with an open circuit, a
short circuit, or both (Open and Short).
Auto Length and Loss vs. Direct Compensation
Auto Length and Loss compensation is a descriptive correction type: The effects of the test fixture
connection are traced back to quantities that are commonly used to characterize transmission lines. Use
this correction type if your test fixture connections have suitable properties in the considered frequency
range:
 The electrical length is approximately constant.
 The loss varies essentially due to the skin effect.