Basic Measurement Examples
R&S
®
ESRP
93
Getting Started 1316.4697.02 ─ 07
An RF sinusoidal signal is displayed using the passband characteristic of the
defined resolution filter (RBW). Its specified bandwidth is the 3 dB bandwidth of
the filter.
Two signals with the same amplitude can be resolved if the resolution bandwidth
is smaller than or equal to the frequency spacing of the signal. If the resolution
bandwidth is equal to the frequency spacing, the spectrum display shows a level
drop of 3 dB precisely in the center of the two signals. Decreasing the resolution
bandwidth makes the level drop larger, which thus makes the individual signals
clearer.
Higher spectral resolution at a narrower bandwidth is accomplished through lon-
ger sweep times at the same span. Reducing the resolution bandwidth by a factor
of 3 increases the sweep time by a factor of 9.
Example:
Separating Two Signals
The two signals have a level of -30 dBm each at a frequency spacing of 30 kHz
Table 7-2: Signal generator settings (e.g. R&S SMU)
Level
Frequency
Signal generator 1
-30 dBm
128,00 MHz
Signal generator 2
-30 dBm
128,03 MHz
1. Set the signal analyzer to the default state by pressing the [PRESET] key.
The R&S
ESRP is set to its default state.
2. Select "Spectrum" mode.
3. Set the center frequency to 128.015 MHz and the frequency span to 300 kHz.
a) Press the [FREQ] key and enter 128.015 MHz.
b) Press the [SPAN] key and enter
300 kHz
.
4. Set the resolution bandwidth to 30 kHz and the video bandwidth to 1 kHz.
a) Press the [BW] key
Measuring Signal Spectra with Multiple Signals
