Tektronix SPG8000A, Руководство пользователя

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118 SPG8000A User Manual
Use this formula to calculate K
X
and K
X
2
terms for a sweep with the DC point
at mid - screen:
where R
aspect
is the aspect ratio (width ÷ height) of the active format.
The Horizontal Sweep zone plate (H Sweep) is a “K
X
2
- only” zone plate. (See
Figure 34 .)
Figure 34: A “K
X
2
-only” zone plate
K
YT
parameter
Display name: KYT (V Ch. V Freq.)
Units: c/aph per second (c/aph/s)
The K
YT
(V Ch. V Freq.) parameter controls the change in vertical sine frequency
over time. Setting K
YT
to 1.0, for example, causes the vertical frequency to
increase by one c/aph each second. If KY is initially 0.0, then the frequency will
be 10 c/aph after ten seconds, 20 c/aph after twenty seconds, and so forth. The
frequency will increase until it reaches the maximum for the active format, then
the phase of the signal will “flip” by 180° (the frequency will become “negative”)
and the frequency will continue to increase through DC in a repetitive cycle.
K
XY
parameter
Display name: KXY (V Ch. H Freq.)
Units: c/aph per active picture height (c/aph
2
)
The K
XY
(V Ch. H Freq.) parameter sets the change in horizontal frequency
as a function of the vertical position in the video frame. To see the effects
of this parameter, set the waveform monitor to view one selected line only.
Then, with K
XY
set to approximately 25 (all other coefficients left at 0.0),
look at line waveforms from top to bottom of the frame. The horizontal
frequency increases slightly on each succeeding line, reaching 25 c/aph on
the last line of active video. The result can be thought of as a vertically
arranged “sweep” signal.