Instrument Function
R&S
®
SMC100A
170Operating Manual 1411.4060.32 ─ 09
5.4.1.1 Enabling/Disabling Analog Modulations using the MOD On/Off Key
The MOD ON/OFF key switches the modulations on and off.
MOD ON/OFF
Press the MOD ON/OFF key to enable/disable analog modulations.
Pressing the key again restores the status that was active before the last switch-off.
"MOD OFF" is displayed in the info line of the header next to the "Level" field.
Remote command:
[:SOURce<hw>]:MODulation[:ALL][:STATe] on page 308
5.4.1.2 Modulation Sources
The following modulations use internal and external modulation sources:
●
Amplitude modulation
●
Pulse modulation
●
Frequency modulation
●
Phase modulation
Internal Modulation Sources
An LF generator and a pulse generator are available as internal modulation sources.
The LF generator supplies sinusoidal. The pulse generator provides single and double
pulse modulation with selectable pulse widths and periods.
See also Chapter 5.5.1, "Overview of LF Generator", on page 179.
External Modulation Sources
The modulation input MOD EXT at instrument front provides the external modulation
sources for amplitude, frequency and phase modulation.
The external modulation signal for AM, FM and PM 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 V, otherwise modulation distortions might
occur.
The maximum modulation frequency is 100 kHz for frequency and phase modulation,
and 50 kHz for amplitude modulation.
The PULSE EXT/INST TRIG connector at the rear of the instrument controls the exter-
nal pulse modulation. The input shows some hysteresis with threshold levels of
0.5 V/1.5 V. The voltage must not exceed 10 V.
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 (-).
Modulation
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