
ADVANCE INFORMATION
DDP 3310B
Micronas
7
2.1.4. Dynamic Peaking
Especially with decoded composite signals and notch
filter luminance separation as input signals, it is neces-
sary to improve the luminance frequency characteris-
tics. With transparent high-bandwidth signals, it is
sometimes desirable to soften the image.
In the DDP 3310B, the luma frequency response is
improved by
“
dynamic
”
peaking. It adapts to the ampli-
tude and the frequency of the input signal. Small AC
amplitudes are sharpened while large AC amplitudes
remain nearly unmodified.
The dynamic range can be adjusted from
14 to
+
14 dB for small high-frequency signals. There is sep-
arate adjustment for signal overshoot and for signal
undershoot. For large signals, the dynamic range is
limited by a non-linear function that does not create
any visible alias components. The peaking can be
switched over to
“
softening
”
by inverting the peaking
term by software.
The center frequency of the peaking filter is selectable
from 2.5 MHz to 3.2 MHz. For S-VHS and for notch fil-
ter color decoding, the total system frequency
responses for both PAL and NTSC are shown in Fig.
2
–
1 and Fig. 2
–
2. (All frequencies refer to a 50/60-Hz
video signal).
Fig. 2
–
1:
Dynamic peaking frequency response
Fig. 2
–
2:
Total frequency response for peaking filter and S-VHS, PAL, NTSC
dB
MHz
20
5
-5
-10
-15
-20
0
2
4
6
8
10
15
10
0
dB
MHz
20
5
-5
-10
-15
-20
0
2
4
6
8
10
15
10
0
dB
MHz
20
5
-5
-10
-15
-20
0
2
4
6
8
10
15
10
0
CF= 3.2 MHz
CF= 2.5 MHz
S-VHS
dB
MHz
20
5
-5
-10
-15
-20
0
2
4
6
8
10
15
10
0
dB
MHz
20
5
-5
-10
-15
-20
0
2
4
6
8
10
15
10
0
CF= 3.2 MHz
CF= 2.5 MHz
PAL/SECAM
dB
MHz
20
5
-5
-10
-15
-20
0
2
4
6
8
10
15
10
0
dB
MHz
20
5
-5
-10
-15
-20
0
2
4
6
8
10
15
10
0
CF= 2.5 MHz
CF= 3.2 MHz
NTSC