- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄372110 > SAA5290PS (NXP Semiconductors N.V.) Economy teletext and TV microcontrollers PDF資料下載
參數(shù)資料
| 型號： | SAA5290PS |
| 廠商： | NXP Semiconductors N.V. |
| 英文描述： | Economy teletext and TV microcontrollers |
| 中文描述： | 經(jīng)濟圖文電視和電視微控制器 |
| 文件頁數(shù)： | 23/33頁 |
| 文件大小： | 360K |
| 代理商： | SAA5290PS |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁當前第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁
February 1995
23
Philips Semiconductors
Preliminary specification
One page Economy Teletext/TV
microcontroller
SAA5290
TELETEXT DECODER FUNCTIONAL DESCRIPTION
Data slicer
The data slicer extracts the digital teletext data from the
incoming analog waveform. This is performed by sampling
the CVBS waveform and processing the samples to
extract the teletext data and clock.
Acquisition timing
The acquisition timing is generated from a logic level
positive-going composite sync signal ‘VCS’. This signal is
generated by the sync separator circuit which adaptively
slices the sync pulses at 50% of their height. It is able to do
this over a wide range of sync amplitudes by using the
same basic principle used on VIP1 (SAA5230) and VIP2
(SAA5231).
Figure 4 is a block diagram showing the principles of
operation. It relies upon the fact that the ratio of the sync
width to the line time is approximately 13 : 1. In order to
slice the sync pulse at the correct 50% level two currents
are generated.
One is constant and is proportional to the difference
between the black level of the video and the slicing level.
The other is produced only when the video is below the
slicing level, and is also proportional to the difference
between the slicing level and the input, but has a
magnitude13 times greater.
The black level is determined by a sync-gated peak
detector. The video is negatively peak detected into an
external capacitor (BLACK, pin 25), but not during the
sync pulse VCS. The two currents are integrated on the
CVBS input coupling capacitor and the net effect is to alter
the mean input voltage until the (fixed) slicing level is
correct.
The acquisition clocking and timing are locked to the VCS
signal using a digital phased-locked-loop. The phase error
in the acquisition phase-locked-loop is detected by a
signal quality circuit which disables acquisition if poor
signal quality is detected.
Fig.4 Sync separator block diagram.
handbook, full pagewidth
MLC105
VDD
Vref
Vref
Vref
CVBS
(= slicing level)
FILTER
FILTER
gated negative peak detector
BLACK
VCS
1/3Vi
1/39Vi
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SAA5290ZP | One page Economy Teletext/TV microcontroller |
| SAA5291PS | Economy teletext and TV microcontrollers(經(jīng)濟的圖文電視和TV控制器) |
| SAA5296APS | Economy teletext and TV microcontrollers(經(jīng)濟的圖文電視和TV控制器) |
| SAA5296PS | Economy teletext and TV microcontrollers(經(jīng)濟的圖文電視和TV控制器) |
| SAA5355 | Single-chip colour CRT controller FTFROM |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SAA5290ZP | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:One page Economy Teletext/TV microcontroller |
| SAA5290ZP/NV | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:One page Economy Teletext/TV microcontroller |
| SAA5291 | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Economy teletext and TV microcontrollers |
| SAA5291A | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Economy teletext and TV microcontrollers |
| SAA5291AH | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Economy teletext and TV microcontrollers |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。