R&S ESR Series, Руководство пользователя

Страница: 310 / 1126

Spectrum Measurements
R&S
®
ESR
307 User Manual 1175.7068.02 ─ 12
Remote command:
Detector:
Δ
Limit:
CALCulate<n>:MARKer<m>:FUNCtion:FMEasurement:LIMit<k>:DELTa?
on page 783
CALCulate<n>:MARKer<m>:FUNCtion:FMEasurement:LIMit<k>:
CONDition ?
on page 782
CALCulate<n>:DELTamarker<m>:FUNCtion:FMEasurement:LIMit<k>:
DELTa?
on page 782
CALCulate<n>:DELTamarker<m>:FUNCtion:FMEasurement:LIMit<k>:
CONDition ?
on page 781
Result:
CALCulate<n>:MARKer<m>:FUNCtion:FMEasurement:RESult?
on page 783
CALCulate<n>:DELTamarker<m>:FUNCtion:FMEasurement:RESult?
on page 782
6.1.1.9 CISPR APD Measurement (Amplitude Probability Distribution)
The Amplitude Probability Distribution (APD) is a statistical measurement that shows
the "cumulative distribution of the probability of time that the amplitude of disturbance
exceeds a specified level" (CISPR 16-1-1, Amendement 1:2005). So, basically, the
measurement determines the likelihood that a disturbance is above a specified level at
a particular frequency (the measurement is usually performed on a fixed frequency).
The amplitude of the disturbance is expressed in terms of the corresponding field
strength or voltage at the receiver input.
The APD is measured at the output of the envelope detector. Therefore, the APD
yields the probability information over the entire disturbance envelope within the mea-
surement bandwidth and a particular period of time.
The APD function has the following advantages.
●
It provides an alternative way to present peak and average measurements (for
example for microwave ovens in accordance with CISPR 11).
●
It is able to calculate true average values.
●
It shows high sensitivity and allows you to measure, for example, a single impulse.
●
It allows you to measure unsteady levels.
APD vs CISPR APD
Note that the R&S ESR also provides an APD measurement for general purposes.
This general APD function does not comply with CISPR 16-1-1 in various aspects and
cannot be used for CISPR APD measurements.
The result display is made up out of a diagram and a table.
●
The diagram contains a graphical representation of the measurement results (the
probability with which a particular amplitude occurs).
The x-axis represents the amplitude, the y-axis the (cumulative) probability.
Measurements