Spectrum Analyzer Mode
R&S
®
Spectrum Rider FPH
188
User Manual 1321.1011.02 ─ 11
Performing gated sweeps
After the gate settings are configured, it is possible to perform a gated sweep measure-
ment.
To get appropriate results, you have to set the gate delay and gate length in a way that
the measurement is active during the interesting part of the signal. You can also modify
the sweep time to match the horizontal axis to the length of the signal and thus set the
gate delay and gate length parameters more accurately. Alternatively, you can also
perform an auto gate setting to determine the gate delay and gate length of the signal
automatically.
The gate delay parameter defines the time between the trigger event and the begin-
ning of the actual measurement. The gate length defines the duration of the measure-
ment, before it is interrupted and the next gate signal is anticipated to resume the mea-
surement.
The minimum requirement for RBW is 30 kHz for gated trigger. The R&S Spectrum
Rider configures the RBW to 30 kHz if a lower value is used.
Sweep time is set at an integer multiple of frame duration (e.g. a multiple settings of 10
ms for LTE frame duration). Default sweep time is set to 10 ms and minimum sweep
time allowed is 5 ms.
In case of gate settings conflict, the R&S Spectrum Rider will set the trigger to free run.
Before re-enabling the gated trigger, you need to perform one of the following:
●
revert to previous settings and correct the gate setting
●
perform gate setting with adjusted gate length
Gate setting should be done at least once before performing gated sweep.
Example:
Using a signal source, i.e R&S SMU to generate an EUTRA/LTE signal (TDD duplex-
ing, downlink (OFDMA)) at 1 GHz, -40 dBm. Connect the signal source RF output to
the RF input connector of the R&S Spectrum Rider.
The example performs a gated trigger measurement using "AutoGate High" function to
determine the gate length and gate delay of the desire part of the signal. The measure-
ment starts after the delay time has passed and measurement take places over the
period of the gate length. The result is a stable LTE signal for measurement.
1. Press [SWEEP] key.
2. Select "Trigger" softkey.
3. Select the "Gate Settings" menu item.
The R&S Spectrum Rider opens a softkey submenu to control the gate settings. At
the same time, the R&S Spectrum Rider switches into time domain, as indicated in
the display. See
(time domain with initial gate setting).
4. Select "Manual SWT" softkey and set the sweep time in a way that the portion of
interest of the signal is visible on the screen.
Configuring Spectrum Measurements
www.allice.de
Allice Messtechnik GmbH
