Overview - Keysight Technologies X Series Measurement Manual

APD (Amplitude Probability Distribution) Measurements

Overview

Overview
CISPR (Comite International Special des Perturbations Radioelectriques)
introduces Amplitude Probability Distribution measurement (APD) in
Amendment 1:2005 to CISPR 16-1-1:2003 as a new weighting method to
accurately determine the electromagnetic disturbance emitted by electrical
appliances or equipment, which degrade the performance of digital
communication system, especially the impact of impulsive disturbances on the
system.
The APD of disturbance is defined as the complimentary cumulative
distribution function of the absolute amplitude of the signal you are measuring.
Alternatively, it can be estimated from the measured data by finding the ratio
of the time the signal amplitude exceeds a certain level (x0) and the total signal
analysis time.
The APD measurement results can be used to evaluate its interference
potential on digital communication systems according to CISPR 16-3,
sub-clause 4.7. The experimental results show the correlation between APD
and performance of digital communication systems (for example, BER and
throughput results). Therefore APD measurement may be applicable to the
compliance test of some products or product families, such as microwave
ovens.
The APD measurement is passed when a limit line against its associated APD
trace:
— the Disturbance Level (E meas) at the specified Probability is within the
— the Probability of time (ρ meas) at the specified Disturbance Level is within
The following sections describe the operation of the APD measurement
included in the EMI Receiver measurement application. The APD
measurements results show the power statistical data both in graphical format
and in a signal list on the screen.
It is important to note that compliant measurements require to be running on
an EMI receiver or a spectrum analyzer that is CISPR-compliant, like Keysight
N9038A MXE.
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limit; And,
the limit.
Keysight N6141A Measurement Guide