Measurements and Results
R&S
®
FSW
151
User Manual 1173.9411.02 ─ 43
5. Set the reference level to
0
dBm
(= level of the signal generator).
6. Set the sweep time to
2
ms
([SWEEP] > "Sweep Time Manual").
The R&S
FSW shows the GSM burst continuously across the display.
7. Use the trigger source "Video" and the trigger slope "Rising" to trigger on the rising
edge of the burst and shift the start of the burst to the center of the display (see
"Measuring the Edges of a GSM Burst with High Time Resolution"
8. Activate power measurement within the activation phase of the burst in zero span.
a) Press the [MEAS] key.
b) Select "Time Domain Power".
c) Select "Time Dom Power Config".
d) Set the "Limits" state to "On".
e) Select the "Left Limit" input field.
f) By turning the rotary knob clockwise, move the vertical line "S1" to the start of
the burst.
g) Select the "Right Limit" input field.
h) By turning the rotary knob clockwise, move the vertical line "S2" to the end of
the burst.
i)
Note down the power result for the burst, indicated by the "TD Pow RMS" result
in the marker table.
9. Measure the power during the deactivation phase of the burst by switching the trig-
ger slope to "Falling" ([TRIG] > "Trigger/ Gate Config").
The R&S
FSW initiates triggering in response to the falling edge of the burst. This
shifts the burst to the left-hand side of the measurement diagram. The power is
measured in the deactivation phase.
Figure 7-19: Measurement of the signal-to-noise ratio of a GSM burst signal in zero span
Basic Measurements
