Figure 54: Measuring Rise Time Using Variable Gain In Eye - Tektronix WFM8200 User Manual

Monitoring the SDI Physical Layer
To Make Automatic Eye
Measurements
108

Figure 54: Measuring rise time using variable gain in eye

NOTE.
If you use the measurement cursors to manually measure the eye
waveform, you might get a different result than that shown in the automatic eye
measurements readout. This is because the automatic amplitude measurement
uses histograms to be minimally affected by overshoot, ringing, and noise on
the signal. Similarly, the automatic rise time and fall time measurements use
histograms to find the centers of the distributions of 20% and 80% crossings. The
difference between manual and automatic measurements is usually insignificant
for clean, symmetrical signals.
1. Perform the initial setup for Eye measurements. (See page 105, Eye
Measurement Set Up.)
2. Press and hold the STATUS button to display the pop-up menu.
3. Select Display Type and then select SDI Status.
4. Note the Eye waveform measurements in the SDI Status display readouts.
Automatic Eye measurements (and a histogram of the Eye waveform) are
also displayed in the Eye Waveform display when expanded to the single,
full-screen display.
WFM8200 and WFM8300 Waveform Monitors