Common Measurement Settings
R&S
®
ESW
176
User Manual 1177.6298.02 ─ 08
10.8.1.1
Defining the Scope of the Measurement - Frequency Range
The frequency range defines the scope of the signal and spectrum to be analyzed.
In the receiver application, the R&S
ESW supports several measurement concepts.
●
Measurements over a specified frequency range
The frequency range is defined by start and stop frequency. This concept is usually
used by scans. If you are using a scan table, you can split the frequency range into
several smaller subranges.
●
Measurements on a single frequency
The measurement is performed on a single frequency. This concept is used by bar-
graph measurements, for example.
●
Measurements on a set of single frequencies
The measurement is performed on a set of single frequencies that are within a
specified frequency range. This concept is used by the final measurement, for
example.
●
Measurements within a frequency span around the receiver frequency
The measurement shows the spectrum around the receiver frequency in greater
detail. This concept is used by the IF analysis.
In any way, make sure that the receiver frequency is at least twice as large as the reso-
lution bandwidth. If you use a frequency that is lower, the R&S
ESW automatically
reduces the measurement bandwidth.
10.8.1.2
Coping with Large Frequency Ranges - Logarithmic Scaling
In a linear display, the frequencies are distributed linearly across the x-axis. That
means the entire frequency range is divided by the number of measurement points,
and the distance between measurement points is equal. Linear scaling is useful to
determine precise frequencies within a small range.
1 MHz
10 MHz
Figure 10-6: Linear x-axis scaling: the distance between the measurement points is equal, e.g.
200
kHz
However, if high and low frequencies appear in the same display, it is difficult to deter-
mine individual frequencies precisely or to distinguish frequencies that are close
together.
In a logarithmic display, lower frequencies are distributed among a much larger area of
the display, while high frequencies are condensed to a smaller area. Now it is much
easier to distinguish several lower frequencies, as they are spread over a wider area.
Logarithmic scaling is useful for overview measurements when a large frequency
range must be displayed in one diagram.
However, with logarithmic scaling, the frequency resolution between two measurement
points deteriorates with higher frequencies.
Frequency and Span Configuration
