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Making Measurements
Measuring Amplifiers
To show the second harmonic's power level relative to the fundamental power in dBc, press
and select . This display mode lets you see the relationship
between the fundamental and second or third harmonic in dBc. (Refer to Figure 1-46.)
Figure 1-46 2nd Harmonic Power Level in dBc
Additional Harmonic Measurements
Vector network analyzers are commonly used to characterize amplifier gain compression versus frequency
and power level. This is essentially linear characterization since only the relative level of the fundamental
input to the fundamental output is measured. The narrow band receiver is tuned to a precise frequency and,
as a result, is immune from harmonic distortion. You may want to quantify the harmonic distortion itself.
Figure 1-47 illustrates a simultaneous measurement of fundamental gain compression and second harmonic
power as a function of input power.