Tektronix LE160, Техническое справочное руководство

Страница: 27 / 30

This is the skew between the Ch 1 DP and DN outputs of the linear
equalizer.
5. Check the Channel 2 skew between DP and DN:
a. Connect the channel 1 oscilloscope output to the Ch 2 + output of the
linear equalizer.
b. Connect the channel 2 oscilloscope output to the Ch 2 - output of the
linear equalizer.
c. Measure the positive crossing point on channel 1 of the oscilloscope.
Record the value in "Scope Ch 1 measurement", row H in the Test
Record.
d. Measure the negative crossing point on channel 2 of the oscilloscope.
Record the value in "Scope Ch 2 measurement", row I in the Test
Record.
e. Subtract the value from row A minus row B and enter in row J in the Test
Record.
f. Reverse the oscilloscope input cables at the output of the linear equalizer.
Oscilloscope Channel 1 should now be connected to the Ch 1 - output of
the linear equalizer and oscilloscope Channel 2 should be connected to
the Ch 1 + output of the linear equalizer.
g. Measure the negative crossing point on channel 1 of the oscilloscope.
Record the value in "Scope Ch 1 measurement", row K in the Test
Record.
h. Measure the positive crossing point on channel 2 of the oscilloscope.
Record the value in "Scope Ch 2 measurement", row L in the Test
Record.
i. Calculate the difference between the measurements in row D minus row
E. Record the difference in row M in the Test Record.
j. Calculate the difference between the entries in row J minus row M.
Divide that result by 2. Enter the divided value in row N.
This is the skew between the Ch 2 DP and DN outputs of the linear
equalizer.
6. Verify that the entries in rows G and N meet the specifications in the table
near the top of the Test Record.
Performance verification
LE160 & LE320 Specifications & Performance Verification 13