Tektronix SPG8000A, User Manual

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SPG8000A User Manual 115
Zone plate
signal Pattern control parameter Parameter definition
V Sine Vertical Frequency (c/aph) The vertical frequency is actually the K
Y
coefficient. The
maximum frequency (c/aph) corresponds to the number of
active video lines in a field of the active video standard.
For example, when an 1125-line system is output (which
has 1080 active lines), K
Y
can be any value between –540
and 540.
V Sweep V Sweep Frequency (maximum c/aph, or
multiple)
The vertical sweep frequency is actually the K
Y
2
coefficient.
For numbers greater than maximum, dividing the displayed
value by that maximum will give twice the number
of complete DC-max-DC sweeps per field (sweeps =
(K
Y
2
/K
Y
)/2). For example, in a standard with 1080 lines per
field, a vertical sweep frequency of 2160 c/aph
2
would result
in one complete frequency sweep down the picture.
Zone Plate Dependent Parameters
The zone plate dependent parameters are listed below the Frequency pattern
control parameter in each of the zone plate patterns; they are the same for all
zone plate patterns.
Frequency
(pattern control) parameter
Display name: Frequency
Units: c/aph per active picture height (c/aph
2
)
The instrument 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 41.)
K
Y
2
parameter
Display name: KY^2 (V Sweep)
Units: c/aph per active picture height (c/aph
2
)
The K
Y
2
(V Sweep) parameter sets the increase (or decrease) in vertical frequency
down the frame. (K
Y
2
compares to K
X
2
as K
Y
compares to K
X
.) Again, a good way
to see the effect of K
Y
2
is to view the field on a waveform monito r. With KY set to
0.0, a K
Y
2
coefficient of 10 will result in the apparent vertical sine wave changing
from DC to 10 c/aph from the top of the picture to the bottom.
To center the “DC point” at mid - screen, set K
Y
2
to – 2 times K
Y
.
The Vertical Sweep zone plate is a “K
Y
2
- only” zone plate. (See Figure 32 .)