3. High-level measurements

• Compression point measurement

This measurement is traditionally carried out using a spectrum analyzer and an RF generator, the level of which is gradually increased. The curve shown in figure 4 can then be plotted. More conveniently, on some network analyzers, the source power can be varied and 20 lg ½S ₂₁ ½ displayed as a function of power, at a given frequency. The compression point is obtained directly: a 1 dB drop from the horizontal asymptote corresponding to the composite gain at low level.

• Intersection measurement

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