Chapter 2 387
Performance Verification Tests
52. First LO OUTPUT Power Accuracy (Option AYZ only)
52. First LO OUTPUT Power Accuracy (Option
AYZ only)
This test applies only to analyzers equipped with external mixing
(Option AYZ).
This test verifies that analyzers with external mixing (Option AYZ)
meet their specification for First LO (local oscillator) output level. The
flatness of the First LO output determines the flatness of
measurements made using external mixers. In this test, a calibrated
power sensor is connected to the First LO output to measure the power
level at frequencies between 2.9 GHz and 7.1 GHz.
The analyzer is put into external mixing mode using a harmonic
number of –10. The tuned frequency of the spectrum will therefore be
321.4 MHz (the frequency of the Second IF) below the Tenth harmonic
of the First LO. A 321.4 MHz frequency offset is used so that the center
frequency will be exactly 10 times the First LO frequency. Setting the
center frequency step size to 2 GHz allows the LO frequency to be
stepped in 200 MHz increments.
The related adjustment for this performance test is “LO Power
Adjustment.”
Equipment Required
Power meter
Microwave power sensor
Adapter, type-N (m) to SMA (f)
Figure 2-72 First LO Output Amplitude Accuracy Test Setup