Power measurement is accomplished by using a high-power calibrated coupler (or high-power calibrated attenuator) which gets attached to the Amplifier RF output connector. Attached to the calibrated coupler (or attenuator) is a calibrated power meter/sensor for absolute power measurements.
The RF input drive to the amplifier is increased from the signal source until the power meter reads the rated power specified for the product under test. This test verifies the amplifier meets the specified RF output power. Normal practice for a basic product verification is to record 35 frequency points; example: low, mid & high band point or as desired.