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參數(shù)資料
| 型號： | ADV7184 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | Multiformat SDTV Video Decoder with Fast Switch Overlay Support |
| 中文描述： | 標(biāo)清多格式視頻解碼器支持快速開關(guān)重疊 |
| 文件頁數(shù)： | 28/108頁 |
| 文件大?。?/td> | 925K |
| 代理商： | ADV7184 |
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ADV7184
DCT[1:0] Digital Clamp Timing, Address 0x15 [6:5]
The clamp timing register determines the time constant of the
digital fine clamp circuitry. It is important to realize that the
digital fine clamp reacts very quickly since it is supposed to
immediately correct any residual dc level error for the active
line. The time constant of the digital fine clamp must be much
quicker than the one from the analog blocks.
Rev. 0 | Page 28 of 108
By default, the time constant of the digital fine clamp is adjusted
dynamically to suit the currently connected input signal.
Table 35. DCT Function
DCT[1:0]
Description
00
Slow (TC = 1 sec).
01
Medium (TC = 0.5 sec).
10 (default)
Fast (TC = 0.1 sec).
11
Determined by the ADV7184, depending on the
I/P video parameters.
DCFE Digital Clamp Freeze Enable, Address 0x15 [4]
This register bit allows the user to freeze the digital clamp loop
at any time. It is intended for users who would like to do their
own clamping. Users should disable the current sources for
analog clamping via the appropriate register bits, wait until the
digital clamp loop settles, and then freeze it via the DCFE bit.
0 (default)—The digital clamp is operational.
1—The digital clamp loop is frozen.
LUMA FILTER
Data from the digital fine clamp block is processed by three sets
of filters. The data format at this point is CVBS for CVBS input
or luma only for Y/C and YPrPb input formats.
Luma antialias filter (YAA). The ADV7184 receives video at
a rate of 27 MHz. For 4× oversampled video, the ADCs
sample at 54 MHz, and the first decimation is performed
inside the DPP filters. Therefore, the data rate into the SDP
core is always 27 MHz. The ITU-R BT.601 recommends a
sampling frequency of 13.5 MHz. The luma antialias filter
decimates the oversampled video using a high quality, linear
phase, low-pass filter that preserves the luma signal while at
the same time attenuating out-of-band components. The
luma antialias filter has a fixed response.
Luma shaping filters (YSH). The shaping filter block is a
programmable low-pass filter with a wide variety of
responses. It can be used to selectively reduce the luma
video signal bandwidth (needed prior to scaling, for
example). For some video sources that contain high
frequency noise, reducing the bandwidth of the luma
signal improves visual picture quality. A follow-on video
compression stage may work more efficiently if the video is
low-pass filtered.
The ADV7184 has two responses for the shaping filter: one
that is used for good quality CVBS, component, and
S-VHS type sources, and a second for nonstandard CVBS
signals.
The YSH filter responses also include a set of notches for
PAL and NTSC. However, it is recommended to use the
comb filters for YC separation.
Digital resampling filter. This block is used to allow
dynamic resampling of the video signal to alter parameters
such as the time base of a line of video. Fundamentally, the
resampler is a set of low-pass filters. The actual response is
chosen by the system with no requirement for user
intervention.
Figure 16 through Figure 19 show the overall response of all
filters together. Unless otherwise noted, the filters are set into
a typical wideband mode.
Y-Shaping Filter
For input signals in CVBS format, the luma shaping filters play
an essential role in removing the chroma component from a
composite signal. YC separation must aim for best possible
crosstalk reduction while still retaining as much bandwidth
(especially on the luma component) as possible. High quality
YC separation can be achieved by using the internal comb filters
of the ADV7184. Comb filtering, however, relies on the
frequency relationship of the luma component (multiples of the
video line rate) and the color subcarrier (Fsc). For good quality
CVBS signals, this relationship is known; the comb filter
algorithms can be used to separate out luma and chroma with
high accuracy.
For nonstandard video signals, the frequency relationship may
be disturbed and the comb filters may not be able to remove all
crosstalk artifacts in an optimum fashion without the assistance
of the shaping filter block.
An automatic mode is provided. Here, the ADV7184 evaluates
the quality of the incoming video signal and selects the filter
responses in accordance with the signal quality and video
standard. YFSM, WYSFMOVR, and WYSFM allow the user to
manually override the automatic decisions in part or in full.
The luma shaping filter has three control registers
YSFM[4:0] allows the user to manually select a shaping filter
mode (applied to all video signals) or to enable an automatic
selection (dependent on video quality and video standard).
WYSFMOVR allows the user to manually override the
WYSFM decision.
WYSFM[4:0] allows the user to select a different shaping
filter mode for good quality CVBS, component (YPrPb),
and S-VHS (YC) input signals.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ADV7184BSTZ | 功能描述:IC DECODER VID SDTV MULTI 80LQFP RoHS:是 類別:集成電路 (IC) >> 接口 - 編碼器，解碼器，轉(zhuǎn)換器 系列:- 產(chǎn)品變化通告:Development Systems Discontinuation 26/Apr/2011 標(biāo)準(zhǔn)包裝:1 系列:- 類型:編碼器 應(yīng)用:DVB-S.2 系統(tǒng) 電壓 - 電源，模擬:- 電壓 - 電源，數(shù)字:- 安裝類型:- 封裝/外殼:模塊 供應(yīng)商設(shè)備封裝:模塊 包裝:散裝 其它名稱:Q4645799 |
| ADV7185 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Professional NTSC/PAL Video Decoder with 10-Bit CCIR656 Output |
| ADV7185KST | 制造商:AD 制造商全稱:Analog Devices 功能描述:Professional NTSC/PAL Video Decoder with 10-Bit CCIR656 Output |
| ADV7186 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Video Decoder and Display Processor |
| ADV7186BBCZ | 功能描述:IC VIDEO DECODER 196CSPBGA RoHS:是 類別:集成電路 (IC) >> 線性 - 視頻處理 系列:- 產(chǎn)品變化通告:Product Discontinuation 07/Mar/2011 標(biāo)準(zhǔn)包裝:3,000 系列:OMNITUNE™ 類型:調(diào)諧器 應(yīng)用:移動電話，手機(jī)，視頻顯示器 安裝類型:表面貼裝 封裝/外殼:65-WFBGA 供應(yīng)商設(shè)備封裝:PG-WFSGA-65 包裝:帶卷 (TR) 其它名稱:SP000365064 |
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