HD9690 Series HDTV Graticule Generator Manual
Page 3-12
Revision 1.5
FRONT PANEL
OPERATION
3.3.1.1.
Display Mode
Display modes are used to control the appearance of the object on the output video, ex. dashed and solid
lines.
3.3.1.2.
Centre Mode
If the object’s centre mode is enabled, the object’s centre will be fixed to the horizontal and vertical centre
of the clean aperture. (The on screen display will show the setting of the object’s centre mode
.)
The
centre mode will not be available when the
Force Centre Setup Menu
item is set to
yes.
(The on screen
display will show
all objects centred.)
3.3.2. Aspect Ratio Mode
The aspect ratio mode of the
mask, box, and ellipse
objects forces the selected object’s size parameters
to follow one of the following fixed aspect ratios
: 1:1, 4:3(1.33:1), 14:9 (1.55:1), 1.67:1, 16:9 (1.78:1),
1.85:1, 2.35:1
. (The on screen display will show the aspect ratio as
fixed aspect
.) When the object aspect
ratio is set to
Off
the object's dimensions are not constrained to follow a fixed aspect ratio. (The on screen
display will show the aspect ratio as
user aspect
.)
When an object is being controlled in fixed aspect ratio mode, the horizontal size will be adjusted first, then
the aspect ratio applied to determine the correct vertical size. The pixel aspect ratio and the object aspect
ratio are both used to calculate the vertical size of an object of a given horizontal size. The following
formula is used to calculate the vertical size:
Number of V lines = Number of H pixels x (Pixel aspect ratio / Object aspect ratio)
This calculation will be rounded to the closest line or to the closest line pair if object centering is on.
Example: Draw a box in 1080 video standard with an aspect ratio of 4:3, with a width of 708 pixels. The
Pixel aspect ratio for 1080 HD formats is 1.00.
V lines = H pixels x (Pixel AR / Object AR
= 708 x (1 / (4/3))
= 480
The selected object aspect ratio defines the ideal dimensions of the object. The on screen and front panel
aspect ratio displays show the actual object aspect ratio rounded to 2 decimal places. It may vary slightly
from the selected object aspect ratio due to the effects of rounding to the closest line, and object
centering.
3.3.3. Controlling the Object Attributes
The
CTRL SEL
button is used to select which
object
attributes (colour, line width, size, position, etc.) will
be adjusted using the shaft encoder knobs. The particular items available in the
CTRL SEL
menu are
determined by settings in the
SETUP
menu and the object
MODES
in force at the time. The on screen
display will show the active control on the
ctrl
line.
Sections 3.4 to 3.8 give a complete description of how to control each of the individual objects. In the
sections describing the
CTRL SEL
items, the relevant settings from the
MODE
and
SETUP
menus are
shown where necessary.
