VPC 323xD, VPC 324xD
ADVANCE INFORMATION
dB
10
Table 2–3: Scaler modes
0
-10
-20
Mode
Scale
Factor
Description
Compression 0.75
4:3 → 16:9
4:3 source displayed on
a 16:9 tube,
linear
with side panels
-30
-40
Panorama
4:3 →16:9
non-
linear
compr
4:3 source displayed on
a 16:9 tube,
Borders distorted
-50
2
4
6
8
10
MHz
Zoom
4:3 → 4:3
1.33
linear
Letterbox source (PAL+)
displayed on a 4:3 tube,
vertical overscan with
cropping of side panels
dB
10
0
-10
-20
Water glass
16:9 → 4:3
non-
linear
zoom
Letterbox source (PAL+)
displayed on a 4:3 tube,
vertical overscan, bor-
ders distorted, no crop-
ping
-30
-40
20.25 →
13.5 MHz
0.66
sample rate conversion
to line-locked clock
-50
1
2
3
4
5
MHz
2.5.4. Horizontal Peaking-filter
Fig. 2–12: YCrCb downsampling lowpass-filter
The horizontal scaler block offers an extra peaking fil-
ter for sharpness control. The center frequency of the
peaking filter automatically adopts to the horizontal
scaling ratio. Three center frequencies are selectable
(see Fig. 2–13: )
2.5.2. Horizontal Prescaler
To achieve a horizontal compression ratio between
1/4 and 1/32 (e. g. for double window or PIP operation)
a linear downsampler resamples the input signal by 1
(no presampling), 2, 4 and 8.
– center at sampling rate / 2
– center at sampling rate / 4
– center at sampling rate / 6
2.5.3. Horizontal Scaling Engine
The filter gain is adjustable between 0 – +10 dB and a
coring filter suppresses small amplitudes to reduce
noise artifacts.
The scaler contains a programmable decimation filter,
a 1-H FIFO memory, and a programmable interpola-
tion filter. The scaler input filter is also used for pixel
skew correction, see 2.3.10. The decimator/interpola-
tor structure allows optimal use of the FIFO memory. It
allows a linear or nonlinear horizontal scaling of the
input video signal in the range of 0.25 to 4. The con-
trolling of the scaler is done by the internal Fast Pro-
cessor.
16
Micronas
MICRONAS [ MICRONAS ]
