Specifications

40 Chapter 6
Making Distortion Measurements
Identifying Analyzer Generated Distortion
Making Distortion Measurements
Identifying Analyzer Generated Distortion
High level input signals may cause analyzer distortion products that
could mask the real distortion measured on the input signal. Using
trace 2 and the RF attenuator, you can determine which signals, if any,
are internally generated distortion products.
Using a signal from a signal generator, determine whether the
harmonic distortion products are generated by the analyzer.
Step 1. Connect the signal generator to the analyzer input.
Step 2. Set the source frequency to 200 MHz with an amplitude of 0 dBm.
Step 3. Set the analyzer center frequency and span:
Press
Preset, Factory Preset (if present).
Press
FREQUENCY Channel, Center Freq, 400, MHz.
Press
SPAN X Scale, Span, 500, MHz.
The signal produces harmonic distortion products (spaced 200 MHz
from the original 200 MHz signal) in the analyzer input mixer as shown
in Figure 6-1.
Figure 6-1 Harmonic Distortion (ESA left, PSA right)
Step 4. Change the center frequency to the value of the first harmonic:
Press
Peak Search, Next Peak, Marker→, Mkr→CF.
Step 5. Change the span to 50 MHz and re-center the signal:
Press
SPAN X Scale, Span, 50, MHz.
Press
Peak Search, Marker→, Mkr→CF.
Step 6. Set the attenuation to 0 dB:
Press
AMPLITUDE Y Scale, Attenuation, 0, dB.