Specifications

1820/1822 Operator’s Manual
Section 3
General Operating Information
Getting Started
This section will help the first time user become familiar
with the operation of the 1822 and how it interfaces with
an oscilloscope. Operation of the 1820 is very similar
except an external voltage source is needed for operation
of the comparison and differential offset modes.
To carry out the following exercises, the operator will
need an oscilloscope and a general purpose function
generator.
Power Connection
Check to make sure the POWER switch located on the
rear panel is in the OFF position. Connect the power
cord to an appropriate power source. The 1822 will
operate on a 50 or 60 Hz AC power source with a
nominal voltage range from 100 volts to 250 volts.
Connection to and Setting up the Oscilloscope
Connect a 50 f2 coaxial cable between the AMPLIFIER
OUTPUT BNC on the 1822 rear panel and the
oscilloscope’s input connector. If the oscilloscope has
1 M tq and 50 if2 input capability, select 50 f2. If the
oscilloscope has only a I M f2 input, terminate the
coaxial cable at the oscilloscope’s input with a 50
feed-through terminator. It is important that the 1822 be
terminated into 50 fL
Set the oscilloscope scale factor to 50mV/div. Set the
oscilloscope’s input coupling to GND or OFF and
position the trace to center screen. Do not move the
oscilloscope position setting after this initial set-up.
Change the oscilloscope input coupling to DC.
1822 Front Panel Operation
Change the POWER switch located on the 1822’s rear
panel to ON and observe the 1822’s front panel
indicators. Initially, there will be about a 2 second delay
and then each function, other than the upper and lower -
3dB points, will have one indicator light lighted. The red
OVERLOAD and yellow OVERDRIVE lights will be
lighted as well as all segments in the Precision Voltage
Generator display. After approximately 3 seconds, the 1822
will be set to its power-up reset state. This state is as follows:
+ INPUT
OFF
- INPUT
OFF
HF-3dB POINT
No lights on (full BW)
LF-3dB POINT
No lights on (DC)
GAIN
Xl
ATTENUATOR +10
INPUT RESISTANCE
1M
PRECISION VOLTAGE GENERATOR
+ 00.000
COMPARISON or DIFFERENTIAL COMPARISON
EFFECTIVE GAIN -10
Attenuator and Gain Operation
Connect the function generator output to the +INPUT BNC
connector and apply a sinewave of 50 kHz and 0.5V peak
amplitude. Push the DC button on the 1822’s +INPUT. The
signal on the oscilloscope should be 2 divisions peak to peak
amplitude. Adjust the oscilloscope’s time/division and trigger
to display at least two complete cycles of the waveform.
Press the +1 ATTENUATOR button. The waveform’s
magnitude on the oscilloscope’s display will increase by a
factor of 10 and extend off the top and bottom of the screen.
The XI light will be lighted in the EFFECTIVE GAIN
display. Reduce the function generator’s output until the
oscilloscope’s display is again 2 divisions peak to peak. The
overall sensitivity of the 1822 and the oscilloscope is now
50mV/div.
Now press the Xl0 GAIN button. Observe the following
changes: The +INPUT DC light will momentarily go out and
its OFF light will be lighted before returning to their previous
states. This momentary change is the result of the 1822
automatically adjusting its DC Balance. The XI0 light will be
lighted in the EFFECTIVE GAIN display and the display on
the oscilloscope will again extend off screen. The overall
sensitivity of the 1822 and the oscilloscope is now 5mV/div.
3-1