Tektronix WFM2200A, User Manual

Page: 223 / 276

Checking gamut
Signals that are legal and valid in one signal representation may not be legal in
another representation. Specifically, signals which are legal in the Digital YCbCr
representation may not be legal if transcoded to RGB or encoded to NTSC / PAL.
Any signal that fails this test is considered out of gamut.
You can set custom gamut thresholds using the CONFIG > Gamut Thresholds
submenu or you can reset the gamut thresholds to default values.
Your instrument supports multiple displays and alarms to detect out-of-gamut
signals. The flexible, tiled display allows you to simultaneously view several
gamut measurements to learn which is most appropriate for a given application.
The displays are and their uses follow:
■ Diamond display: Checks that SDI signals conform to legal RGB gamut
space.
■ Split Diamond display: Separates the upper and lower diamonds to show
excursions below black; otherwise it is identical to the Diamond display.
■ Arrowhead display: Checks if an SDI signal is legal for composite color
space.
The Diamond, Split Diamond, and Arrowhead displays have adjustable
thresholds. If the signal goes outside the area defined by the thresholds, the signal
is out of gamut. If these limits are exceeded, then the instrument can generate
alarms if configured to do so.
For composite waveforms, the legal limit is simply the maximum level allowed
for the combination of luma and chroma. This limit depends on the application.
For example, a video tape machine may be able to record and play out signals
with higher luma and chroma components than a transmitter.
WFM2300 and WFM2200A Waveform Monitors User Manual 201