HP 54645A, Руководство пользователя и сервисное руководство

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To verify threshold accuracy
Instructions for HP 54645D
These instructions apply only to the HP 54645D Mixed-Signal Oscilloscope.
1
Press
Label/Threshold
. Select Threshold Menu , and select D0-D7
under the
Set
softkey. Then, select the variable threshold softkey
just to the right of
ECL
.
2
For each of the threshold levels shown in the following table:
a
Use the Entry knob on the oscilloscope to select the threshold voltage
shown in the table.
b
On the function generator front panel, enter the DC offset voltage
shown in the table. Use the multimeter to verify the voltage.
Activity indicators for D0-D7 should show all at a digital high. These
activity indicators appear on the status line at the top of the display
for several seconds after pressing the variable threshold softkey.
c
Using the Modify down arrow on the function generator, decrease
offset voltage in 10-mV increments until all activity indicators for
digital channels D0-D7 show the digital channels at a digital low.
Record the function generator voltage in the performance test record.
d
Using the Modify up arrow on the function generator, increase offset
voltage in 10-mV increments until all activity indicators for digital
channels D0-D7 show the digital channels at a digital high. Record the
function generator voltage in the performance test record.
3
Using the 8-by-2 test connector, connect digital channels D8-D15 to
the output of the function generator. Connect the D0-D7 ground lead
to the ground side of the 8-by-2 connector.
4
Repeat steps 1 and 2, using digital channels D8-D15 for D0-D7.
Table 7-3 Threshold Test Settings
Threshold Voltage DC Offset Voltage
+5.0 +5.252 V
±
1 mV DC
–5.0 –4.748 V
±
1 mV DC
0.0 +0.102 V
±
1 mV DC
Testing, Adjusting, and Troubleshooting
To verify threshold accuracy
7-14