User`s guide

7-102 Agilent Technologies E5500 Phase Noise Measurement System
Absolute Measurement Examples
Microwave Source
Figure 7-20 Noise Characteristics for the Microwave Measurement
If the output amplitude of your UUT is not sufficient to provide an
adequate measurement noise floor, it will be necessary to insert a low
noise amplifier between the UUT and the Agilent/HP 70422A input.
(Refer to “Inserting an Device” in Chapter 6, “Absolute Measurement
Fundamentals” for details on determining the effect that the amplifier’s
noise will have on the measured noise floor.)