Tektronix SPG8000 Technical Reference page 117

SDI rise and fall time
SPG8000 Specifications and Performance Verification
Perform this test with the instrument in factory mode. (See page 19, Set SPG8000
to Factory Mode.)
This procedure uses the same equipment setup as the previous procedure. (See
Figure 29 on page 101.)
CAUTION.
The serial output level can be adjusted when the instrument is in
factory mode. Be careful not to accidentally adjust this level, as this will invalidate
the factory calibration. If you need to perform a serial output level adjustment,
see the SPG8000 service manual for the procedure.
1. Connect a 75 Ω cable from the SDI 1B connector in the SPG8000 through the
SMA to BNC adapter (with or without the 6 dB pad) to the trigger direct input
on a sampling oscilloscope.
2. Connect a cable from the SDI 1A output of SPG8000 to the TCA75 BNC
on the oscilloscope adapter.
3. Set the SDI calibration signal for SDI 1A to 20 bits square on the SPG8000 as
follows:
a. Press the SDI button on the SPG8000.
b. Use the up (▲) arrow button to select SDI 1 : CALIBRATION. You
should see Channel 1 : Top in the menu.
c. Press the ENTER button.
d. Press the right (►) arrow button to select 20 bits Square.
4. On the oscilloscope, set the horizontal scale to 200 ps.
5. Set the oscilloscope to averaging 16 and set the record length to 4000 points.
6. On the oscilloscope, select Measurement 4 and then Pulse-Timing for the
Rise Time.
7. Select the Reference Level tab from Measure and set the reference high to
80% and the low to 20%.
8. Select Measurement 5 and then Pulse-Timing for the Fall Time.
9. Select the Reference Level tab from Measure and set the reference high to
80% and the low to 20%.
10. Set the horizontal position to put the rising edge of the waveform about
2.5 divisions to the left of center.
11. Measure the rise time and record the result in the test record.
12. Use the horizontal position knob to put the falling edge about 2.5 divisions
left of center.
13. Measure the fall time and record the result in the test record.
Performance verification
103