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Time-Gating Measurement
Similar to P-Series power meter,
P-Series modular power meter offers
extensive triggering facilities for
making time-gated measurements.
This allows useful average, peak and
peak-to-average ratio measurements
of complex modulation formats to be
taken.
This demonstration shows the
versatility of the time-gating features
of P-Series modular power meter, by
setting up four independent times
gates on a TDMA signal to measure
various power parameters, as shown
in Figure 11. This fi gure illustrates a
GSM900 pulse, where Gate 2 provides
the burst average power over the
useful GSM time period and Gate 1
indicates the peak-to-average power
over the whole timeslot. A pulse droop
measurement can be obtained from
Gate 4/Gate 3.
From Figure 11, time-gating is used
to measure the average power of the
useful period (5% to 95% of the burst
duration), peak power, peak-to-aver-
age ratio and pulse droop in a GSM900
signal.
The four gates that are confi gured will
setup to display and measure the burst
average power, peak-to-average ratio
and the pulse droop. The upper
window is confi gured to display the
burst power (Gate 2) and the lower
window is confi gured to display the
peak-average ratio (Gate 1) and the
pulse droop (Gate 4/Gate 3). (See
Figure 12)
Figure 11. Powerful data confi guration routines permit measurements
during 4 gate time, each with 2 data "feeds" for display.
Computed parameters such as peak-to-average ratio can also be
displayed.
Instructions
On the ESG:
1. Setup the GSM900 format for
P-Series modular power meter
and ESG E4438C.
Instructions
On the P-Series soft front panel:
1. Select the GSM900 predefi ned
preset value.
2. Setting up gates
3. Set up measurement display
10
Keystrokes
(Refer to ESG setup, Page 8)
Keystrokes
[Preset]. Use the arrow softkey to
choose {GSM900}. [Select] {Confi rm}
[Channel], {Gates Setup}. Use the
arrow softkey to select the gate and
change its value.
Gate1 Start: 0 ms
Length: 600 ms
Gate 2 Start: 20 ms
Length: 520 ms
Gate 3 Start: 20 ms
Length: 40 ms
Gate 4 Start: 500 ms Length: 40 ms
Upper Window
Use the DISPLAY up/down softkey
to highlight the upper window. [Disp],
{Disp Type}, {Single Numeric}.
Lower Window
Use the DISPLAY up/down softkey
to highlight the lower window. [Disp],
{Disp Type}, {Dual Numeric}.
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