Optimizing 802.11Ac Sem Measurements - Keysight X Series Manual

Making WLAN Measurements
Making Spectrum Emission Mask Measurements

Optimizing 802.11ac SEM Measurements

Sometimes SEM measurements fail because of using inaccurate Gate settings
for the WLAN burst signal.
The following steps describe how to optimize your analyzer Gate settings and
get the best 802.11ac SEM measurements.
To measure the burst length, you can use Power vs Time measurement.
See
Steps
1. Select the desired radio
standard.
2. Enter the center
frequency.
3. Select the
measurement.
4. If necessary, reduce the
mechanical attenuator
manually down to 0 dB.
5. Turn on the Gate View.
6. Change the Res BW for
Ref Channel from 100
kHz to 8 MHz.
7. Change the Res BW for
each Offset from 100
kHz to 8 MHz.
8. Adjust the settings for
Gate Start and Gate
Stop.
40
"Optimizing CCDF Measurements" on page
Action
MODE Setup
a. Press
802.11ac 802.11ac (80
,
MHz)
.
FREQ Channel
a. Press
GHz
.
MEAS Spectrum
a. Press ,
Emission Mask
.
AMPTD Y Scale
a. Press
Attenuation
, Mech Atten and
0 dB
enter .
Sweep/Control
a. Press
Gate View
and switch
Meas Setup
a. Press
Channel Res BW
,
MHz
.
Meas Setup
a. Press
Offset/Limits Select Offset
,
Offset A More Res BW
, ,
8 MHz
enter .
b. Set the same Res BW for Offset
B, C, D, E, F, respectively.
Gate Delay
a. Press
to move GATE START line to the
rising edge of a burst.
Gate Length
b. Press
Knob to move GATE STOP line to
the falling edge of the same
burst.
32.
Notes
Rad io Std
, ,
5.18
, ,
When the signal level is low, for example,
,
-30 dBm, set the attenuation to 0 dB.
Gate
, ,
On
to .
Ref
The maximum Res BW setting is 8 MHz to
,
set the accurate Gate Delay and Gate
8
, and enter
Length in time domain.
By default, Offset E and F are turned off.
,
,
and
Make sure the MIN FAST line (blue) is on
and use Knob
the left of the GATE START line (green).
Figure 2-13 on page 41
See the
and use
Keysight WLAN Measurement Guide
.