- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄369517 > BT848A Single-Chip Video Capture for PCI PDF資料下載
參數(shù)資料
| 型號： | BT848A |
| 英文描述： | Single-Chip Video Capture for PCI |
| 中文描述： | 單芯片的PCI視頻捕捉 |
| 文件頁數(shù)： | 25/141頁 |
| 文件大?。?/td> | 1149K |
| 代理商： | BT848A |
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頁第23頁第24頁當前第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頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁第68頁第69頁第70頁第71頁第72頁第73頁第74頁第75頁第76頁第77頁第78頁第79頁第80頁第81頁第82頁第83頁第84頁第85頁第86頁第87頁第88頁第89頁第90頁第91頁第92頁第93頁第94頁第95頁第96頁第97頁第98頁第99頁第100頁第101頁第102頁第103頁第104頁第105頁第106頁第107頁第108頁第109頁第110頁第111頁第112頁第113頁第114頁第115頁第116頁第117頁第118頁第119頁第120頁第121頁第122頁第123頁第124頁第125頁第126頁第127頁第128頁第129頁第130頁第131頁第132頁第133頁第134頁第135頁第136頁第137頁第138頁第139頁第140頁第141頁
Brooktree
15
F
UNCTIONAL
D
ESCRIPTION
UltraLock
L848A_A
Bt848/848A/849A
Single-Chip Video Capture for PCI
UltraLock
The Challenge
The line length (the interval between the midpoints of the falling edges of succeed-
ing horizontal sync pulses) of analog video sources is not constant. For a stable
source such as studio quality source or test signal generators, this variation is very
small:
±
2 ns. However, for an unstable source such as a VCR, laser disk player, or
TV tuner, line length variation is as much as a few microseconds.
Digital display systems require a fixed number of pixels per line despite these
variations. The Bt848 employs a technique known as UltraLock to implement
locking to the horizontal sync and the subcarrier of the incoming analog video sig-
nal and generating the required number of pixels per line.
Operation Principles of
UltraLock
UltraLock is based on sampling using a fixed-frequency, stable clock. Since the
video line length will vary, the number of samples generated using a fixed-frequen-
cy sample clock will also vary from line to line. If the number of generated samples
per line is always greater than the number of samples per line required by the par-
ticular video format, the number of acquired samples can be reduced to fit the re-
quired number of pixels per line.
The Bt848 requires an 8*Fsc (28.64 MHz for NTSC and 35.47 MHz for PAL)
crystal or oscillator input signal source. The 8*Fsc clock signal, or CLKx2, is di-
vided down to CLKx1 internally (14.32 MHz for NTSC and 17.73 MHz for PAL).
CLKx2 and CLKx1 are internal signals and are not made available to the system.
UltraLock operates at CLKx1 although the input waveform is sampled at CLKx2
then low pass filtered and decimated to CLKx1 sample rate.
At a 4*Fsc (CLKx1) sample rate there are 910 pixels for NTSC and 1,135 pixels
for PAL/SECAM within a nominal line time interval (63.5
μ
s for NTSC and 64
μ
s
for PAL/SECAM). For square pixel NTSC and PAL/SECAM formats, there
should only be 780 and 944 pixels per video line, respectively. This is because the
square pixel clock rates are slower than a 4*Fsc clock rate, i.e., 12.27 MHz for
NTSC and 14.75 MHz for PAL.
UltraLock accommodates line length variations from nominal in the incoming
video by always acquiring more samples, at an effective 4*Fsc rate, than are re-
quired by the particular video format and outputting the correct number of pixels
per line. UltraLock then interpolates the required number of pixels in a way that
maintains the stability of the original image despite variation in the line length of
the incoming analog waveform.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| BT849A | Single-Chip Video Capture for PCI |
| BT8510EPJC | PCM Transceiver |
| BT857KPJ | Color Encoder Circuit |
| BT8958EHJ50 | xDSL Interface |
| BT8953AEPFC | xDSL Interface |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| BT848AKPF | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Single-Chip Video Capture for PCI |
| BT848KPF | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Single-Chip Video Capture for PCI |
| BT849A | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Single-Chip Video Capture for PCI |
| BT849AKPF | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Single-Chip Video Capture for PCI |
| BT850-SA | 功能描述:BTV4.2 DUAL MODE USB HCI MODULE 制造商:laird - wireless & thermal systems 系列:* 零件狀態(tài):在售 標準包裝:1 |
發(fā)布緊急采購，3分鐘左右您將得到回復。