Tektronix AWVG1, User Manual

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Appendix C: Zone Plates
AWVG1 Wideband Video Generator User Manual
C- 5
Figure C- 4: A K
X
2
-only zone plate
TG 2000 display: KXY (V ch H freq)
Units: c/aph
2
K
XY
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.
The Field Sweep zone plate signal is a K
XY
-only zone plate.
TG 2000 display: KY (V Freq)
Units: c/aph
K
Y
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 AWVG1 Generator
module 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 signal is a K
Y
-only zone plate (see Figure C--5).
K
XY
Parameter
K
Y
Parameter