Measurement Accuracy And Speed; Measurement Considerations - Keysight Technologies N8480 Series Operating And Service Manual

1 Introduction

Measurement Accuracy and Speed

The power meter has no internal ranges. The only ranges you can set are
those of the Keysight N8480 Series power sensors and other Keysight
E- Series power sensors. With a Keysight N8480 Series power sensor
(excluding Option CFT) or E- Series power sensor, the range can be set
either automatically or manually. Use autoranging when you are not sure
of the power level you are about to measure.

Measurement Considerations

While autoranging is a good starting point, it is not ideal for all
measurements. Signal characteristics such as crest factor or duty cycle
may cause the power meter to select a range which is not the optimum
configuration for your specific measurement needs. Signals with average
power levels close to the range switch point require you to consider your
needs for measurement accuracy. When measuring pulse signals, you are
recommended to select manual filtering. This allows you to choose the
averaging to cover the many periods of the pulse signal instead of having
it determined by measurement noise. Selecting manual filtering also
changes the behaviour of the autoranging to help prevent frequency range
changes due to pulses. For a very long pulse periods (more than one
second), it may be better to select UPPER range as this will prevent any
possibility of range changes upsetting the measurement.
18 N8480 Series Power Sensors Operating and Service Guide