Checking Composite Gamut - Tektronix WFM8200 User Manual

Checking Gamut

Checking Composite Gamut

Figure 61: Arrorwhead gamut display plots
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On the Diamond display, monochrome signals appear as vertical lines. Nonlinear
component processing, such as from a gamma corrector that alters white balance,
can cause deviations along the vertical axis.
To isolate gamut bright-ups, try the following:
Use the LINE SEL button to select individual lines.
Use the PICT display to examine the signal (turn on gamut bright-ups in the
Display Settings submenu of the Configuration menu).
Use the Diamond Area or Arrowhead Area settings (found in the Gamut
Thresholds submenu of the Configuration menu) to specify a percentage of the
image pixels to ignore for gamut violations. The Gamut bright-ups, however,
will continue to indicate all Gamut violations.
The Arrowhead gamut display plots luminance (Y) against chrominance (C)
to check if the composite signal adheres to standard gamut. NTSC and PAL
Arrowhead displays (75% Color bars) and indicates the values of the graticule
lines. The arrowhead shape of the graticule results from overlaying the standard
limits for luminance and luminance-plus-peak chrominance. (See Figure 61.)
WFM8200 and WFM8300 Waveform Monitors