Operating Manual 1164.4556.12 - 06
2.37
R&S FSP
Getting Started
Measurements on Modulated Signals
2.5.3.3
Measurement Example 3 – Measuring the Modulation Spectrum in Burst Mode
with the Gated Sweep Function
Since transmission systems compliant to IS136 use a TDMA method, the adjacent
channel power must also be measured in burst mode. An IS136 TDMA frame is
divided into 6 time slots. Two of these slots are assigned to a subscriber. This
means that the ratio of transmit time to off-time for IS136 mobile phones is only 1:3
(e.g. time slots 1 and 4)
The R&S FSP supports the measurement of the adjacent channel power in the
TDMA mode with the Gated Sweep function.
Test setup with the R&S Signal Generator SMIQ:
The R&S SMIQ has to be equipped with options R&S SMIQ-B10 or R&S SMIQ-B20
(modulation coder) and R&S SMIQ-B11 (data generator).
Option R&S SMIQ-Z5 is required to trigger the R&S FSP. This option is connected
to the R&S SMIQ’s parallel output port. The BNC output Trigger 1 of the R&S SMIQ-
Z5 provides a TTL trigger signal on the rising edge of the IS136 burst, which is used
to start the R&S FSP sweep in the Gated Sweep mode.
Settings on signal generator R&S SMIQ:
Switch the signal generator to the IS136 burst mode (time slots 1 and 4 are switched
on, the other time slots are switched off).
The R&S SMIQ is set as follows to generate the signal:
➢
Press the
PRESET
key.
➢
Press the
FREQ
key and enter 850 MHz.
➢
Press the
LEVE
L key and enter -20 dBm.
➢
Press the
RETURN
key.
➢
Select
DIGITAL STANDARD
using the spinwheel and press the
SELECT
key.
➢
Select
NADC
using the spinwheel and press the
SELECT
key.
➢
Press the
SELECT
key.
➢
Select
ON
using the spinwheel and press the
SELECT
key.
➢
Press the
RETURN
key.
Signal
generator
SMIQ
FSP
Ext Ref IN
Ext Ref Out
RF Inp
Ext Gate/Trig IN
SMIQ-Z5
Trigger1
Par Data Output
The R&S FSP’s IF power trigger is not suitable for IS136. It triggers on every
level edge of the input signal. Since the modulation of the IS136 signal causes
level dips even during the transmit burst, there is no way of ensuring that the
R&S FSP is only triggered on the burst edge.
Summary of Contents for R&S FSP Series
Page 1: ...R S FSP Spectrum Analyzer Operating Manual 1164 4556 12 06 Test Measurement Operating Manual ...
Page 24: ...R S FSP Putting into Operation 1 2 Operating Manual 1164 4556 12 06 ...
Page 72: ...R S FSP Manual Operation 3 2 Operating Manual 1164 4556 12 06 ...
Page 793: ...R S FSP Index Operating Manual 1164 4556 12 06 4 11 ...
Page 794: ...R S FSP 4 12 Operating Manual 1164 4556 12 06 ...
Page 795: ...Operating Manual 1164 4556 12 06 4 13 R S FSP ...
Page 796: ...R S FSP 4 14 Operating Manual 1164 4556 12 06 ...
