Tektronix ADA400A Instruction Manual page 14

(reduces) the amplitude of the output signal from the ADA400A Differential
Preamplifier. AC coupling on the oscilloscope interferes with the signal output.
Use the input coupling switch on the preamplifier to select other types of signal
coupling.
Functional Check
The following procedure checks the output level of the ADA400A Differential
Preamplifier and the functionality of the offset controls with no signal applied.
1. Without any connection on the input of the oscilloscope, power on the
oscilloscope and make the following control settings:
Volts/Division 100 mV
Time/Division 100 ps
Input Coupling DC
Input Impedance 1 MQ
2. Adjust the oscilloscope to display a flat signal trace at center screen.
3. Comnect the output of the ADA4O0A Differential Preamplifier (or 1103
TEKPROBE Power Supply) to the input connector of the oscilloscope.
4, With no input signal or voltage connected, make the following control
AC GND DC GND (both inputs)
GAIN 0.1
OFFSET OFF
UPPER BANDWIDTH FULL (1 MHz)
5. Check that the trace on the oscilloscope centers around zero volts and the
OVERRANGE indicator does not light.
6. Set the GAIN switch to each of the higher gain settings and check that the
trace on the oscilloscope is adjustable to center screen.
7. With the GAIN switch on the highest setting, set the ON OFF switch for the
OFFSET controls to ON.
8. Adjust the COARSE and FINE controls to bring the trace to center screen.
9. Set each input separately to AC, DC, and back to GND and check that the
offset controls still bring the trace to center screen for each setting.
10. Return the GAIN setting to .1 and the input coupling switches to GND.
The ADA4O0A Differential Preamplifier is now ready to use. For a complete
performance verification procedure, refer to page 27.
4 ADA4OOA Instruction Manual!