
8712ET/ES and 8714ET/ES Performance Checks
RF Network Analyzers Performance Test Software
Service Guide 1-27
PT04: Dynamic Accuracy
This test measures narrowband ratio measurement accuracy over a range of power levels
at 30 MHz. A 110 dB step attenuator is needed—typically an 8496A or 8496G is used. Two
minimum loss pads must be used with a 75Ω analyzer (Option 1EC).
Test Process.Connect the step attenuator between the test ports on the analyzer. Set the
CW frequency to 30 MHz and select fine system bandwidth (15 Hz). Set the power to 0
dBm for 50Ω analyzers and to 13 dBm for 75Ω analyzers. Record the transmission (or S21)
readings for attenuator settings from 0 dB through 90 dB, in 10 dB increments. Apply the
correction factors for the attenuator setting for each reading before checking against the
specification. The reading at−20 dB should be used as the reference power. Use averaging,
if necessary, to improve the test results. For ES models, repeat the test for S12
measurements.
Specification Verified.This test verifies the “Test Port Input: Dynamic Accuracy”
specification inTable1-9 starting on page1-63
. It checks the magnitude accuracy, but not
the phase accuracy.
If This Test Fails.First, perform the“Switched Gain Correction, Adjustment #102” on
page 2-10. If the problem persists, suspect calibration errors in the step attenuator used to
perform this adjustment; see“The step attenuator's 40 dB card selection (3)” on page 1-17.
Crosstalk can also affect this test; verify that all cables and screws are secure.
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