LeCroy DA1855A Operation - page 14
DA1855A Differential Amplifier
3-14
ISSUED: July 2002
DA1855A-OM-E Rev A
Table 3-5. DA1855A Factory Default Settings
Sensitivity, Position and Offset
Oscilloscopes are designed to maintain their accuracy for that
portion of a signal that is displayed on-screen. When the signal is
large enough to drive the display off-screen, the oscilloscope’s
amplifier must limit the signal in a non-linear mode. Oscilloscopes
are designed so that no matter how the sensitivity, position and
offset controls are set, the operator cannot view this distorted
portion of the signal.
When used with a LeCroy oscilloscope, the setup is automatic to
prevent the user from entering a mode which could result in
displaying a distorted signal resulting from overload.
When used with instruments lacking ProBus interface, the
instrument’s gain and position controls should be properly set to
avoid displaying the non-linear portion of the DA1855A's output
signal when it is in overdrive. This can be accomplished by
observing the two following rules:
1.
Turn the oscilloscope input coupling to “OFF” or “GND”,
set the oscilloscope position control to center screen,
and do not change it! If the oscilloscope has an OFFSET
control, it too should be set to zero. Return the oscilloscope’s
input coupling to “DC”. Subsequently adjust the trace position
on the oscilloscope screen using the DA1855A PVG and
V
DIFF
mode or V
COMP
input. This assures that the oscillo-
scope is set to the center of the DA1855A's dynamic range.
Gain
X1
Attenuation
÷÷10
+ Input Coupling
Off
– Input Coupling
Off
Bandwidth Limit
Full
PVG Voltage
+00.000 V
V
COMP
Off
V
DIFF
Off
Input Resistance
1 M
Ω
Ω
PVG Mode
Roll through zero