Front Panel - LeCroy DA1855A Operation

DA1855A Differential Amplifier

FRONT PANEL

Input Connectors
Attenuators
Gain
Output Termination
3-2
Signals applied to the +INPUT and the –INPUT are connected
either directly to the DA1855A amplifier's inputs or to the input
attenuators. Maximum input voltage is ±200 Vp
A signal connected to the +INPUT will remain its polarity at the
output connector. A signal connected to the –INPUT will be
inverted in polarity.
The input attenuators are passive networks which divide each
signal by ten.
In 1 mode the front panel input connectors are directly
connected to the DA1855A amplifier's differential inputs.
In 10 mode each front panel input connector is connected to a
passive 1 M attenuator. The attenuator output is connected to
the DA1855A amplifier's corresponding differential input. The
signal at each input is attenuated by a factor of ten.
The DA1855A amplifier gain (amplification) is selectable between
X1 and X10. The amplified signal appears at the rear panel
AMPLIFIER OUTPUT connector.
Gain will affect the differential mode output signal by amplifying
the signal difference between the +INPUT and the –INPUT, but
will not affect the common mode signal, the signal common to the
+INPUT and them –INPUT.
Proper gain is obtained when the DA1855A drives a 50
such as an oscilloscope with input impedance set to 50
Automatic 50 termination is obtained when the DA1855A is
connected to a LeCroy oscilloscope through the ProBus
interface.
An instrument with only a 1 M
have a 50 coaxial termination placed on its input connector.
The DA1855A is then connected to the oscilloscope through the
coaxial termination.
ISSUED: July 2002
input impedance available should
DA1855A-OM-E Rev A
load
.