Quantum Data 801GC, 801GF, 801GX manual CheckBy3

CheckBy3

Description	The active video area is equally divided into a
	three by three checkerboard of black and white
	boxes. The primary version has four white boxes
	as shown in the figure on the left. The secondary
	version has five white boxes as shown in the figure
	on the right.

Test	Contrast ratio
Purpose	The pattern is based on a proposed ANSI method
	of measuring the contrast ratio of video projection
	systems.
Method	Using a suitable light meter probe, measure and
	record the light-level reading (in foot lamberts)
	in the center of each of the black and white boxes.
	The contrast ratio is expressed as the average of
	all of the white readings divided by the average
	of all of the black readings.

4-14 Chapter 4: Built-In Images Model 801GC, 801GF & 801GX¥Rev. X1