Tektronix TG700, Руководство пользователя

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HD3G7 HD 3 Gb/s SDI Video Generator
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
, and k
T
2
are constants.
All HD3G7 zone plate patterns are de fi ned with coef fi cients 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 de
fi ned with only one or two
parameters, while the coef fi cients 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 3-31.) This pattern
control parameter is unique to the zone plate signal it is associated with.
When you fi rst enter the zone plate parameters menu for a signal, the pattern
control parameter for that signal is displayed. The pattern control parameter
controls the basic pattern frequency by adjusting the dependent parameters. For
example, if you change the CIRCLE SWEEP Circle Frequency, the generator
adjusts four of the dependent parameters to keep the circle round.
Table 3-31: Zone plate pattern control parameters
Zone plate
signal
Pattern control parameter Parameter de fi nition
Circle Circle Frequency (maximum c/aph) The circle frequency is actually the equivalent of the
maximum vertical sinusoid frequency at the very top
and bottom of the screen (see the discussion of the K
Y
2
parameter). Adjusting the circle frequency has the simple
effect of increasing or decreasing the maximum frequency
at the outer edges of the pattern. However, this adjustment
actually changes the coef
fi cients of four of the zone plate
parameters in order to keep the pattern round and centered
on the screen.
Diagonal Diagonal Frequency (equivalent c/aph)
The diagonal frequency is times the vertical and
horizontal frequencies (c/aph). Adjusting the diagonal sine
frequency changes both the KX and KY coef
fi cients.
H Sine Horizontal Frequency (MHz) The horizontal frequency reported on the display is the real
time frequency of the sine wave that causes the vertical
bar pattern. The maximum frequency is half of the clock
frequency used by the generator for the active video
standard (for example, 74.25 MHz/2 = 37.125 MHz).
TG700 TV Signal Generator Platform User Manual 3–153