ml87v21071 Oki Semiconductor, ml87v21071 Datasheet - Page 43

• Manufacturer Part Number: ml87v21071
• Description: Video Signal Noise Reduction Ic With A Built-in Frame Memory
• Manufacturer: Oki Semiconductor

OKI Semiconductor
Detection of Basic Noise Status Signals
Detection of the basic noise status signal (YBDTO, CBDTO) involves comparing the average noise value
(YBAVRO[6:0], CBAVRO[6:0]) and the noise status comparison value (YAVR1[5:0] (SUB:53h-bit[5:0]),
CAVR1[5:0] (SUB:54h-bit[5:0])) of the blanking period. The noise status is switched when the new status has
continued for four frames or more.
The detection of the noise status signal has the hysteresis characteristic shown in Figure F2-1-6(4). You can
select the characteristic with YAH1(SUB:53h-bit[7]) and CAH1 (SUB:54h-bit[7]).
Table F2-1-7 (7) Noise Status Reduction Direction Detection Hysteresis Settings
Before transition
Before transition
YBDTO=1,CBDTO=1
YBDTO=0,CBDTO=0
Table F2-1-7 (6) Chrominance Blanking Period Noise Status Detection
CBDTO
YBDTO
Table F2-1-7 (5) Luminance Blanking Period Noise Status Detection
Figure F2-1-7 (4) Basic Noise Status Judgment Transition Diagram
0
0
1
1
0
0
1
1
Basic noise status judgment
Set with YAH1, CAH1
CBAVRO[6:0] > CAVR1[5:0] x (hysteresis
CBAVRO[6:0] ≤ CAVR1[5:0] x (hysteresis
YBAVRO[6:0] ≤ YAVR1[5:0] x (hysteresis
YBAVRO[6:0] > YAVR1[5:0] x (hysteresis
0
YAH1
CAH1
CBAVRO[6:0] ≤ CAVR1[5:0]
CBAVRO[6:0] > CAVR1[5:0]
0
1
YBAVRO[6:0] ≤ YAVR1[5:0]
YBAVRO[6:0] > YAVR1[5:0]
YAVR1[6:0]
CAVR1[6:0]
coefficient)
coefficient)
coefficient)
coefficient)
Condition
Condition
Noise reduction direction judging threshold value
Noise reduction direction
switching coefficient
Noise increase direction judging threshold value
3/4
7/8
Basic average noise value
YBAVRO[6:0]
CBAVRO[6:0]
After transition
After transition
CBDTO
YBDTO
0
1
0
1
0
1
0
1
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