Ronde & Schwarz 1304.0004K03, Руководство пользователя

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The Spectrum Application (RF Measurements)
R&S
®
FPL1000
116 User Manual 1178.3370.02 ─ 11
Measuring the Signal-to-Noise Ratio of Burst Signals
When TDMA transmission methods are used, the signal-to-noise ratio or the dynamic
range for deactivation can be measured by comparing the power values during the
activation phase and the deactivation phase of the transmission burst. Therefore, the
R&S
FPL1000 provides a measurement for absolute and relative power in zero span.
In the following example, the measurement is performed using a GSM burst.
Signal-to-Noise Ratio of a GSM Signal
Figure 6-18: Test setup
Table 6-8: Signal generator settings (e.g. R&S SMW)
Frequency 890 MHz
Level 0 dBm
Modulation GSM, one time slot is switched on
1. Select [PRESET] to reset the instrument.
2. Set the center frequency to 890 MHz .
3. Set the frequency span to 0 Hz .
4. Set the resolution bandwidth to 1 MHz .
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 FPL1000 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
step 3 in "Measuring the Edges of a GSM Burst with High Time Resolution"
on page 114).
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.
Measurements and Results