LeCroy DA1855A Operation page 16

DA1855A Differential Amplifier
3-16
In some situations, the user may wish to select amplifier settings
optimized for the lowest noise performance with lower common
mode range. Or, the user may require the amplifier not to change
noise or common mode range when the VOLTS/DIV setting is
changed. These requirements can be met by selecting the
Manual mode in the menu box of user interface window.
Figure 3-2. DA1855A Control Menu in Manual Mode.
When set to Manual mode, the dynamic range of the VOLTS/DIV
knob is limited to the scale factors which can be obtained without
changing the DA1855A gain or attenuation. Thus in Manual gain
control mode, only the scale factor of the oscilloscope will be
changed. In this mode, dedicated menu boxes are displayed for
amplifier Attenuation and Gain. (Refer to figure 3-2).
The available attenuation values which appear in the Value box
will be /10 or /1 independent of the attenuation of any external
probe.
With software version 8.1.0 or higher, the channel OFFSET knob
will control the amplifier's offset rather than the amplifier's PVG
buttons.
ISSUED: July 2002 DA1855A-OM-E Rev A