Instrument Function
R&S
®
SMBV100A
190
Operating Manual 1407.6062.32 ─ 08
Internal Modulation Sources
An LF generator and a pulse generator are available as internal modulation sources for
a fully equipped instrument. The LF generator supplies sinusoidal or rectangular signals.
The optional pulse generator provides single and double pulse modulation with selectable
pulse widths and periods.
The noise generator supplies white noise with selectable bandwidth and level distribution.
See also
chapter 5.4.13.1, "Overview of LF Generator"
External Modulation Sources
The modulation inputs MOD EXT and PULSE EXT at the rear of the instrument are pro-
vided as the external modulation source for amplitude, pulse, frequency and phase mod-
ulation.
The external modulation signal at the input must have a voltage of U
S
= 1 V (U
EFF
= 0.707
V) in order to achieve the displayed modulation depth and range. The input voltage should
not exceed 1.1 Vs, otherwise modulation distortions might occur. With external pulse
modulation, the switching point is max. 2.4 V and the voltage at the input should not
exceed 5 V. The maximum modulation frequency is 10 MHz for frequency and phase
modulation.
Simultaneous Operation of Several Modulations or Other Operating Modes
The table shows the modulations and operating modes which can be activated simulta-
neously (+) or which deactivate each other (-).
AM
FM
PhiM
Pulse
I/Q
Amplitude modulation (AM)
/
+
+
(+)*
-
Frequency modulation (FM)
+
/
-
+
+
Phase modulation (PhiM)
+
-
/
+
+
Pulse modulation
(+)*
+
+
/
+
Vector modulation (I/Q)
-
+
+
+
/
* (+) = compatible with reduced AM modulation performance
5.4.12.2
Amplitude Modulation (AM)
An internal or external source can be selected for amplitude modulation. The LF GEN
modulation generator is available as the internal source. The I/Q modulator is used for
amplitude modulation. Two-tone AM is possible by simultaneously switching on the
external and internal source.
The MOD EXT and PULSE EXT input connectors for external feed of analog modulation
signals are at the rear of the instrument. The coupling mode of the input (AC or DC) can
be selected.
RF Signal and Analog Modulations - RF Block
Summary of Contents for SMBV100A
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