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Technology of Q 2500 colour TV set
For AA and BB display, delay lines must en-
sure that the lines of the 1st and 2nd, and 3rd
and 4th fields contain the same picture infor-
mation when superimposed on one another.
This mode of display allows for very effective
reduction of large-area flicker. A reduction of
interline flicker is, however, not possible, be-
cause intermediate lines are only traced after
20ms.
1.1.4
Mode ABAB
This mode, together with the two described
below, are only possible in conjunction with a
second single-frame picture memory because
of the alternating display of A and B. The de-
flection must also operate in 'abab' raster
form. In this display mode, the signals are not
modified during deflection or image process-
ing operations. In this case, both interline
flicker and large area-flicker can be reduced.
However, jerking effects in moving images
can arise. This form of display is only suitable
for signals where an image is formed from two
fields between which there is no relative
movement. This mode is therefore of interest
only for "Photo CD" or cinema scope films in
PALplus.
Reduction of interline flicker without
movement interpolation (DLC)
Memory 1
Memory 1
Memory 2
retarded
v
A
A
v
A
A
v
B
B
v
B
B
v
A
A
1.1.5 Mode AA'B'B
In this display mode two single-frame pictures,
A' and B', are calculated. By using an interpo-
lation filter the current single-frame, the cur-
rent single-frame delayed by one line and the
Document Q 2500
Deflection
Output
Scanning
pattern
B
A
a
A
A'
b
A
B'
a
B
B
b
B
A
a
signal delayed by one single-frame are com-
pared with one another. If deviations are de-
Interpolation example
10
Memory 1
Memory 1
10
retarded
10
Memory 2
10
Output
tected in one of the signals, this signal is eli-
minated and the values that agree in the other
two signals are retained. If all three signals
vary, an average is formed.
The deflection proceeds as sweep 'abab'. The
calculated A' and B' are written to shifted
scanning system of the 2
frames. A and B are written to the non-shifted
system of frames 1 and 4.
This mode is suitable for the display of hori-
zontal motion between frames. Only small
jerking effects arise between movements.
The mode is used to suppress interline flicker
in normal TV operation.
1.1.6
Mode AA*BB*
In this display mode with respect to the calcu-
lated frames A* and B*, the movement be-
tween the original frames A and B, and be-
tween B and the next A are taken into ac-
count. This movement interpolation (DMI –
Digital Motion Interpolation) takes into account
both horizontal and vertical movements which
cover several lines. This means that when
suppressing
interline
movement over all frames is achieved.
For full frame pictures (films) it is also assured
that no movement between two single-frame
pictures takes place (DMM – Digital Movie
Mode).
In this display mode the deflection is also
'abab'.
9
10
10
x x x
10
9
x x x
x x x
8
8
x x x
10
9
nd
rd
and 3
single
flicker,
continuous
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