Tektronix CSA7404B, Service Manual

Page: 124 / 348

Performance Tests
4- 48
CSA7404B, TDS7704B, TDS7404B, TDS7254B & TDS7154B 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. (For
some settings it is possible that the DC test level appears off screen,
while the measured mean value is within tolerance.)
e. Measure the test signal: Press Close . Read the measurement results at
the measurement statistics measurement readout. See Figure 4--8.
Turn on the
measurement called
mean and read the
results here.
Figure 4- 8: Measurement of DC accuracy at maximum offset and position
f. Check against limits:
H
CHECK that the readout for the measurement readout on screen is
within the limits listed for the current vertical scale and position/off-
set/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 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.
H
Repeat substeps c through f until all vertical scale settings, listed in
Table 4--3, are checked for the channel under test.
g. Test all channels: Repeat substeps a through f for all four channels.