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VCT3801A 参数 Datasheet PDF下载

VCT3801A图片预览
型号: VCT3801A
PDF下载: 下载PDF文件 查看货源
内容描述: 视频/控制/图文电视IC系列 [Video/Controller/Teletext IC Family]
分类和应用: 电视
文件页数/大小: 172 页 / 2219 K
品牌: MICRONAS [ MICRONAS ]
 浏览型号VCT3801A的Datasheet PDF文件第15页浏览型号VCT3801A的Datasheet PDF文件第16页浏览型号VCT3801A的Datasheet PDF文件第17页浏览型号VCT3801A的Datasheet PDF文件第18页浏览型号VCT3801A的Datasheet PDF文件第20页浏览型号VCT3801A的Datasheet PDF文件第21页浏览型号VCT3801A的Datasheet PDF文件第22页浏览型号VCT3801A的Datasheet PDF文件第23页  
ADVANCE INFORMATION  
VCT 38xxA  
dB  
L
a)  
max  
20  
15  
10  
L
t
5
0
L
min  
–5  
–10  
–15  
–20  
b)  
MHz  
0
2
4
6
8
10  
L
t
Fig. 2–13: Dynamic peaking frequency response  
Fig. 2–12: Black-level expansion  
a) luminance input  
b) luminance input and output  
2.10.3.Dynamic Peaking  
Especially with decoded composite signals and notch  
filter luminance separation, as input signals, it is nec-  
essary to improve the luminance frequency character-  
istics. With transparent, high-bandwidth signals, it is  
sometimes desirable to soften the image.  
In the VCT 38xxA, the luma response is improved by  
‘dynamic’ peaking. The algorithm has been optimized  
regarding step and frequency response. It adapts to  
the amplitude of the high-frequency part. Small AC  
amplitudes are processed, while large AC amplitudes  
stay 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 switchable  
from 2.5 MHz to 3.2 MHz. For S-VHS and for notch filter  
color decoding, the total system frequency responses  
for both PAL and NTSC are shown in Fig. 2–14.  
Transients, produced by the dynamic peaking when  
switching video source signals, can be suppressed via  
the priority bus.  
Micronas  
19  
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