Specifications
182011822 Operator’s Manual
Section 1
Specifications
Introduction
The 1820 and 1822 are stand-alone high performance
100 MHz differential amplifiers. They are intended to act
as signal conditioning preamplifiers for oscilloscopes,
digitizers and spectrum analyzers, providing differential
measurement capability to instruments having only a
single-ended input.
The high gain of the 1820/1822 can extend the sensitivity
of an oscilloscope with 1 mV/div to 1 laV/div. A built-in
input attenuator may be separately set to attenuate signals
by a factor of 10, allowing gains of 1000, 100, 10, 1, or
0.1 and common mode dynamic range of +15.5 V (+1)
+155 V (+10). Optional probes further increase the
maximum input signal and common mode ranges in
proportion to their attenuation ratio, but not exceeding the
probe maximum input voltage rating. Effective gain of
the 1822, including probe attenuation, amplifier gain and
attenuator settings, is automatically displayed.
The 1820/1822 has a bandwidth of DC to 10 MHz, but
the operator can select from a full complement of high
and low frequency -3dB points. In critical measurements,
the signal-to-noise ratio can be greatly improved by
restricting the 1820/1822’s bandwidth to the frequency
range of interest.
The 1822 features a built-in Precision Voltage Generator
(PVG) that can be set to any voltage between +15.5 volts
(+10 volts in Differential Offset) with 5 1/2 digit
resolution. Each digit of the voltage generator output can
be individually incremented or decremented. Positive or
negative polarity can be selected. The PVG output can
be selected as an input to the inverting (-) input of the
amplifier for operation as a differential comparator or
applied internally as a true differential offset voltage.
The PVG voltage is also available to be used externally
through a rear panel connector. In the 1820, this
connector becomes an input through which the user can
apply an external voltage to achieve the same differential
offset and comparator functions.
The 1820/1822 operates from 100 to 250 VAC line
without line switching.
A wide range of high performance differential probes are
available from Preamble Instruments for use with the
1820/1822. These include the +1 XC200 low capacitance
probe, XCI00 selectable (+10/+100) attenuation probe,
and the XC350 +100 high impedance (92 M~ / 2.6 pF)
probe. Differential probes with higher voltage ratings are
also available from Preamble Instruments.
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