HD3G7 HD 3 Gb/s SDI Video Generator module
HD3G7 module z
one plate pattern control parameters
NOTE. Zone plate variations can be sinusoidal, square, or triangular. These
discussions of zone plated parameters will re fer to sinusoidal variations for
convenience.
Zone plate patterns are made up of sinusoidal variations in luminance, with the
“peaks” of
the sine waves resulting in white areas on the video screen and the
wave “troughs” shown a s gray or black. The cycles can occur in all three of the
video dimensions: horizontally, or along each line of the picture; vertically, or
“down” the video frame; and temporally (with time). The three d imensions are
oftenreferredtobytheshorthanddesignationsofX,Y,andT.
The luminance of any point in the p icture, physically on the screen and in time, is
determined by the value of sine at that particular point; the value of sine follows
from the phase of the cycle at that point; and (by the definition of a zone plate)
the pha
se of any point is determined by the equation:
where x, y, and t are the coordinates of the point in question and k
Ф
,k
X
,k
Y
,k
T
,
k
XT
,k
YT
,k
XY
,k
X
2
,k
Y
2
,andk
T
2
are consta nts.
All HD3G7 zone plate patterns are defined with coefficients of ten parameters that
correspond to the constants in the above equation. Note that while the possibilities
are virtually endless, most common zone plates are defined with only one or two
parameters, while the coefficients of the remaining parameters are kept at zero.
The HD3G7 Generator module generates six standard zone plate signals: circle
frequency, diagonal frequency, horizontal sine frequency, horizontal sweep
frequency, vertical sine frequency, and vertical sweep frequency. Each standard
zone plate signal has a pattern control parameter. (See Table 3-38.) This pattern
control parameter is unique to the zone plate signal it is associated with.
TG8000 Multiformat Test Signal Generator User Manual 3–175
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