Measurement Basics; Measurement Bandwidth - R&S ESR Series User Manual

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R&S ESR

5.2 Measurement Basics

Measurement basics explain various terms and principles used in the context of EMI
measurements. They also assist you in finding the right configuration for your mea-
surement tasks.
● Measurement
● Detectors...............................................................................................................167
● Trace
● AF
● V-Networks Control
● Transducers.......................................................................................................... 174
● Preamplifier........................................................................................................... 175
● Exported Peak
● Formats for Returned Values: ASCII Format and Binary

5.2.1 Measurement Bandwidth

The measurement bandwidth ("RES BW") defines the bandwidth of the resolution filter.
The RF signal is evaluated and displayed according to the bandpass characteristics of
the resolution filter.
The receiver mode supports the following types of resolution filter.
●
Filters with a 3 dB bandwidth (normal filters).
●
Filters with a 6 dB bandwidth (EMI filters).
The 6 dB bandwidths are designed and required for EMI tests and measurements.
Note that the available bandwidth is limited by the current receiver frequency. The
measurement bandwidth must be less than or equal to half of the current receiver fre-
quency:
BW ≤ f
Additional 6 dB bandwidths
Installing option R&S ESR-B29 adds additional 6 dB bandwidths that are specified for
and comply to MIL, DO and automotive standards.
The resolution filters are implemented as digital Gaussian bandpass filters. Concerning
the attenuation characteristic, the filters behave like analog filters, but their measure-
ment speed is much higher than the measurement speed of comparable analog filters.
This is due to the fact that the transient response can be compensated because the
filters have an accurately defined behavior.
The highest sensitivity is obtained at the smallest bandwidth (10 Hz). If the bandwidth
is increased, the reduction in sensitivity is proportional to the change in bandwidth.
Increasing the bandwidth by a factor of 3 increases the displayed noise by approx.
5 dB (4.77 dB precisely). If the bandwidth is increased by a factor of 10, the displayed
noise increases by a factor of 10, i.e. 10 dB.
User Manual 1175.7068.02 ─ 12
Bandwidth...................................................................................... 166
Modes......................................................................................................... 171
Demodulation.................................................................................................. 172
(LISN)....................................................................................173
List................................................................................................ 176
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in
Receiver Mode
Measurement Basics
Format..........................177
166