Checking Chroma/Luma Delay (Lightning Display) - Tektronix WFM5200 User Manual

Checking Chroma/Luma Delay (Lightning Display)

WFM5200 Waveform Monitor User Manual
The Lightning display can be used for interchannel timing measurements. If the
color-difference signal is not coincident with luma, the transitions between the
color dots will deviate from the center mark of a delay scale. The amount deviated
represents the relative signal delay between luma and the color-difference signal.
1. Connect a signal containing color bar information to an input on the rear panel.
2. Select a tile to view the Lightning Display, then press and hold the VECTOR
button.
3. In the Vector pop-up menu, select Lightning for the Display Type.
4. Set Bar Targets to match your input signal.
5. Select Center Waveform and press the SEL button to center the waveform.
6. Press the VECTOR button to close the pop-up menu.
7. Determine where transitions intersect the delay scales and derive the timing
error in nanoseconds, as deflected from the center mark, using the following
guidelines. (See Figure 45.)
The center mark of the nine marks spanning each green-magenta transition
is the zero error point.
Alignment to a mark toward black means the color-difference signal lags
with respect to luma.
Alignment to a mark toward white means the color-difference signal leads
the luma signal.
The upper half of the display measures the Pb to Y timing; the bottom
half measures the Pr to Y timing.
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