Tektronix SPG8000A, User Manual

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SPG8000A User Manual 119
K
T
parameter
Display name: KT (T Freq.)
Units: cycles per second (c/s)
The K
T
(T Freq.) parameter, if used alone, does not create a “pattern.” Rather, the
entire screen will cycle (sinusoidally) between white and Black. The effect will be
similar on either line or field display of a waveform monitor.
Typically, a small K
T
coefficient is set to add apparent motion to a standard circle,
sine wave, or sweep pattern. To see the picture effects of this parameter, select
any of the standard zone plates and vary K
T
. Note that the K
T
coefficient may be
positive or negative; the sign will determine the direction of the pattern’s motion.
K
Y
parameter
Display name: KY (V Freq.)
Units: cycles per active picture height (c/aph)
The K
Y
(V Freq.) parameter sets the initial vertical frequency of the pattern (it is
analogous to K
X
rotated 90° clockwise). To see the effects of this parameter, set it
to a low number and adjust a waveform monitor to view one or two fields of the
i nstrument SDI output. The variation in the (dc) voltage level from line to line
will give the field waveform the appearance of a sampled sine wave, especially at
a K
Y
of around 5 to 10 c/aph (the sinusoid can become difficult to discern at higher
frequencies). Note that in the Y (vertical) parameters, the c/aph units translate
directly into visible cycles down the frame.
The Vertical Sine zone plate is a “K
Y
- only” zone plate. (See Figure 35.)
Figure 35: A “K
Y
-only” zone plate
K
T
2
parameter
Display name: KT^2 (T Sweep)
Units: cycles per second per second (c/s^2)
The K
T
2
(T Sweep) parameter sets the change in temporal frequency over time. If K
T
is initially 0.0, setting K
T
2
to 1.0 will result in an apparent K
T
of 10.0 after ten
seconds, 20.0 after twenty seconds, and so forth. The temporal frequency will
increase to maximum, return to 0.0, and repeat the cycle as long as the value of K
T
2
remains greater than zero.