Frequency Modulation (Fm); Frequency Modulation Settings - R&S SMB100A Operating Manual

®
R&S SMB100A
Ignore Overvoltage Warning
Suppresses warnings the instrument generates when the modulation signal input is
overloaded.
This function prevents a warning caused by signals, that generally comply with the
specification, but temporarily overload the input, for example due to spikes. The warn-
ing is suppressed in the history, and in the error queue.
Note: This setting is not affected by an instrument preset (PRESET key), *rst or the
Save/Recall function. Only the factory preset resets (enables) this setting.
Remote command:
[:SOURce<hw>]:INPut:MODext:WIGNore

5.4.3 Frequency Modulation (FM)

An internal and/or external source can be selected for frequency modulation. The LF
GEN modulation generator is available as the internal source. Two-tone FM is possible
by simultaneously switching on the external and internal source.
The MOD EXT input connectors for external feed of analog modulation signals are at
the front of the instrument. The coupling mode of the input (AC or DC) can be selected.
Selection between three modulation modes is possible:
●
"Normal" mode with full setting range for modulation bandwidth and FM deviation.
●
"Low Noise" mode with better signal/noise ratio, but reduced setting range for mod-
ulation bandwidth
●
"High Deviation" mode with full setting range for FM deviation and a reduced set-
ting range for modulation bandwidth (see data sheet).
It is not possible to use frequency modulation simultaneously with phase modulation.
See
on page 198 for an overview in detail.
5.4.3.1

Frequency Modulation Settings

To access the "Frequency Modulation" dialog, select "Modulation > Configure > Fre-
quency Modulation" or use the MENU key under "Modulation".
In the upper section of the dialog, you can select the modulation source and activate
modulation. The modulation source can be selected independently for the different
modulation types and the LF output.
The configuration of the selected external and/or internal modulation source is per-
formed in the lower section of the menu (internal source only).
These settings affect all modulations which use the same modulation sources.
Operating Manual 1407.0806.32 ─ 21
"Simultaneous Operation of Several Modulations or Other Operating Modes"
Instrument Function
on page 348
Modulation
202