User's Manual

Performance Tests
4–32
TDS 684A, TDS 744A, & TDS 784A Service Manual
H Use the keypad to set vertical offset to the positive-polarity setting
listed in the table for the current vertical scale setting. The baseline
level will remain off screen.
H Set the generator to the level and polarity indicated in the table for
the vertical scale, position, and offset settings you have made. The
DC test level should appear on screen. (If it doesn’t return, the DC
accuracy check is failed for the current vertical scale setting of the
current channel.)
e. Measure the test signal: Press CLEAR MENU. Read the measurement
results at the Mean measurement readout. See Figure 4–6.
Turn on the
measurement called
mean and read the
results here.
Figure 4–6: Measurement of DC Accuracy at Maximum Offset and Position
f. Check against limits:
H CHECK that the readout for the measurement Mean readout on
screen is within the limits listed for the current vertical scale and
position/offset/generator settings. Enter value on test record.
H Repeat substep d, reversing the polarity of the position, offset, and
generator settings as is listed in the table.
H CHECK that the Mean measurement readout on screen is within the
limits listed for the current vertical scale setting and position/offset/
generator settings. Enter value on test record.