R&S SMJ100A, Operating Manual

Page: 237 / 874

Instrument Function
R&S
®
SMJ100A
221 Operating Manual 1403.7458.32 ─ 14
ALC States
The following description basically explains the ALC states and their principle of opera-
tion. In particular
ALC OFF (Sample & Hold) gives an overview on the function in
terms of the equipment of the generator.
The R&S SMJ offers the ALC states:
●
AUTO
automatically adjusts the output level to the operating conditions.
●
On
enables ALC permanently, regardless of the currently selected mode.
●
Off
deactivates ALC.
The instrument switches to
Sample & Hold (S&H) state, which still allows to main-
tain a constant output level.
The following section explains the functionality of "Sample & Hold", to provide an over-
view and to indicate what is to be considered. "On" and "Auto" require no additional
explanation. Furthermore, find the ALC state settings described in detail in
State - ALC .
ALC OFF (Sample & Hold)
In "S&H" mode, the signal generator switches for a short period of time into CW mode
and activates ALC. ALC adjusts the level to the set value and the generator holds the
value (freeze). Then, the generator switches ALC off again and back to the operating
mode.
RF output behavior during Sample & Hold depends on the configuration of your instru-
ment. Instruments equipped with...:
●
an electronic step attenuator
The level is decreased by 30 dB.
●
a mechanical step attenuator
The level control status is permanently displayed as a status message in the info line.
5.5.7.1 Automatic Level Control Settings
To open the "Automatic Level Control" dialog, select "RF/A Mod" > "Configure" >
"Automatic Level Control" or use the MENU key under "RF/A Mod".
The combined dialog "ALC / UCOR" is divided into the several sections and provides
access to the "Automatic Level Control" settings and to function "User Correction", see
Chapter 5.5.8, "User Correction" , on page 222).
The top sections of the dialog provide access to the level and attenuator settings (see
Chapter 5.5.6.3, "Power-On/EMF Settings" , on page 220 and Chapter 5.5.6.2, "RF
Level Dialog" , on page 216).
RF Signal and Analog Modulations - RF Block