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參數(shù)資料
| 型號： | BA7207 |
| 廠商： | Rohm CO.,LTD. |
| 英文描述： | SECAM chroma signal processor for VHS VCRs |
| 中文描述： | SECAM制式于VHS錄像機色度信號處理器 |
| 文件頁數(shù)： | 12/17頁 |
| 文件大?。?/td> | 250K |
| 代理商： | BA7207 |
12
Video ICs
BA7207AS / BA7207AK
Circuit operation
(1) Recording system (REC)
The input to REC IN is passed through the 4.3MHz BPF-A to remove unwanted frequency components, and is flat-
tened by REC BELL which has an anti-bell characteristic. The flattened signal is wave-shaped by the limiter amplifer,
and processed by the divide-by-four and sync gate circuits. Finally, unwanted frequency components are removed
by the 1.1MHz BPF and the REC EQ prepares the signal for recording playback and the signal is output on REC
OUT. Refer to Fig. 3.
1
26
(
)
24
(
)
(
)
(
)
33
28
4.3MHz
REC
LIMAMP
1BPF
÷
4
REC
EQ
AMP
RECOUT
BA7207AS
(BA7207AK)
100pF
Composite video signal
Fig. 3
27
31
40
(2) Playback system (PB)
The input to PB IN is passed through the 1.1MHz BPF to remove unwanted frequency components, and is flattened
by the PB EQ circuit. The amplitude of the flattened signal fixed by the 1st-stage limiter amplifier, and the frequency
is multiplied by four by the multiplier circuit. Unwanted frequency components generated by the multiplier circuit are
removed by the 2.2MHz BPF and 4.3MHz BPF-A. The signal is wave-shaped by the limiter amplifier, and has gate
applied to it by the sync gate circuit then is passed through the 4.3MHz BPF-B to remove unwanted frequency com-
ponents. The PB BELL circuit restores the original bell characteristic and the signal is output on PB OUT. Refer to
Fig. 4.
18
( )
1BPF
PB
LPF
LIMAMP
2.BPF
4.3MHz
×
2
×
2
AMP
BA7207AS
(BA7207AK)
RF chroma signal
24
26
( )
6
8
( )
11
( )
PB
AMP
( )
AMP
PBOUT
LIMAMP
4.3MHz
PB
TRAP
fc
6
2.2MHz
Fig. 4
2
5
10
31
27
20
( )
(3) Sync gate timing circuit
REC and PB SYNC gate operation is as follows. The gate closes closes in synchronous with the SYNC IN input
pulse during the synchronous signal pulse (SYNC) horizontal scan interval (64
μ
s period). During vertical retrace
(32
μ
S period), the input pulse period becomes shorter than the horizontal scan interval. This is detected by the built-
in vertical synchronous detector circuit which closes the gate. Refer to Fig. 5.
Horizontal scan interval
Vertical retrace interval
4
μ
s
64
μ
s
32
μ
s
SYNCIN
REC / PBOUT
Fig. 5
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| BA7207AK | 制造商:ROHM 制造商全稱:Rohm 功能描述:SECAM chroma signal processor for VHS VCRs |
| BA7207AS | 制造商:ROHM 制造商全稱:Rohm 功能描述:SECAM chroma signal processor for VHS VCRs |
| BA7207AS/AK | 制造商:ROHM 制造商全稱:Rohm 功能描述:Video LSIs |
| BA7212FS | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Consumer IC |
| BA7212S | 制造商:Panasonic Industrial Company 功能描述:IC |
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