R&S 1129.7246.03, Operating Manual

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R&S ESU Instrument Functions
Tracking Generator – Option R&S FSU-B9
4.330 Operating Manual 1302.6163.12 - 03
4.10.6 External Modulation of the Tracking Generator
MODULATION
The MODULATION softkey opens a submenu for selecting different modulation
modes.
The time characteristics of the tracking generator output signal can be influenced by
means of external signals (input voltage range -1 V to +1 V).
Two BNC connectors at the rear panel are available as signal inputs. Their function
changes depending on the selected modulation:
• TG IN I / AM and
• TG IN Q / FM
The modulation modes can be combined with each other and with the frequency off-
set function up to a certain degree. The following table shows which modulation
modes are possible at the same time and which ones can be combined with the fre-
quency offset function.
Table 4-7 Simultaneous modes of modulation (tracking generator)
# = can be combined
EXT AM The EXT AM softkey activates an AM modulation of the tracking generator output
signal.
The modulation signal is applied to the TG IN I / AM connector. An input voltage of
1 V corresponds to 100% amplitude modulation.
Switching on an external AM disables the active I/Q modulation.
Remote command:
SOUR:AM:STAT ON
EXT FM The EXT FM softkey activates the FM modulation of the tracking generator output
signal.
The modulation frequency range is 1 kHz to 100 kHz, the deviation can be set in 1-
decade steps in the range of 100 Hz to 10 MHz at an input voltage of 1 V. The phase
deviation h should not exceed the value 100.
Phase deviation h = deviation / modulation frequency
EXT AM
EXT FM
EXT I/Q
MODULATION OFF
Modulation Frequency
offset EXT AM EXT FM EXT I/Q
Frequency offset # # #
EXT AM # #
EXT FM # #
EXT I/Q #