AKM公司的AK8825是带有3路(RGB) DAC的HD/SDTV多格式视频编码器.在SDTV模式, 输入信号SMTE-125M / ITUR-R.BT601, 656和Y/Cb/Cr 4:2:2格式兼容,而在HDTV模式,输入信号SMPTE-274M (1080i), SMPTE296M (720p)和Y/Cb/Cr 4:2:2兼容.本文介绍了AK8825的主要性能,方框图以及分量视频编码器方框图, NTSC/PAL复合视频编码器方框图, 525i/625i 模式方框图, 1080i/720P模式方框图以及系统应用连接图.

AK8825 HD/SD Multi Format Video Encoder with 3ch DAC
The AK8825 is a HD/SD TV Video Encoder with onchip 3-channel 10bit DAC.

As input data, in SDTV encoder mode, SMTE-125M / ITUR-R.BT601, 656 compatible Y/Cb/Cr 4:2:2 formats (8bit) are accepted and in HDTV encoder mode, SMPTE-274M (1080i), SMPTE296M (720p) compatible Y/Cb/Cr 4:2:2 formats (8bit x 2) are accepted.

As input data capture method, either a Synchronous mode to be made by detecting encoded EAV signal or a mode to synchronize with externally-fed H/V SYNC signal is selectable.

Outputs of CVBS / SDY / SDC and HDY / HDPB / HDPR and R / G / B analog signal can be output exclusively.
VBI signal and Macrovision signal can be also superimposed on output in addition to Video signals by register setting.

AK8825 supports I2C compatible interface as Micro-Processor interface.
主要特性：
Component Video Encoder
- Compatible Input Data
SMPTE125M-1995 / ITU-R BT601 (525i/625i)
SMPTE293M-1996 / ITU-R BT1358 (525p/625p)
SMPTE274M-1998 (1080i)
SMPTE296M-2001 (720p)
- Input Signal Format (525i / 625i, 525p / 625p, 1080i, 720P)
Y/Cb/Cr 4:2:2 (8bit x 1: 525i/625i)
Y/Cb/Cr 4:2:2 (8bit x 2: 525p/625p/1080i/720p)
RGB 6:6:6
RGB 5:6:5
- Input Clock
27MHz (525i / 625i / 525p / 625p) / 74.25MHz (1080i/720p)
- Output Signals
Y/Pb/Pr Interlace
Y/Pb/Pr Progressive
(EIA 770.2, EAI 770.3)
- Input Signal Synchronization
ITU-R.BT 656 I/F (EAV Decode)
Slave operation by HSYNC / VSYNC
(525i: ITU-R. BT601 Compatible 625i / 525p / 625p / 1080i / 720p; CEA-861-D Compatible)
- VBID (CGMS-A), CC/XDS, WSS, CEA-805-B (Type A/B)
- Macrovision 525i / 625i Rev.7.1.1L, 525p/625p Macrovision Progressive 1.2
- Internal Color bar Generator
- Internal Black Burst Generator
- Adjustable Y / Pb / Pr Delay Function
NTSC / PAL Composite Video Encoder
- NTSC-M, PAL-B, D, G, H, I. M, N Encoding
- Composite Video Output / S-Video Output
- Compatible Input Data
SMPTE125M-1995 / ITU-R BT601(525i/625i) Y/Cb/Cr 4:2:2 (8bit x 1)
RGB 6:6:6
RGB 5:6:5
- Input Signal Synchronization
ITU-R.BT 656 I/F (EAV Decode)
Slave operation by HSYNC / VSYNC
( 525i / 625i: ITU-R. BT601 Compatible)
- Input Clock
27MHz
- VBID(CGMS-A), CC/XDS, WSS
- Macrovision Rev. 7.1.L
RGB Video DAC
- RGB output
- Input Data Format
RGB 6:6:6
RGB 5:6:5
- Input Clock
54MHz (max)
Common Specification
- 10bit DAC x 3ch (max operating speed 150MHz)
- I2C BUS I/F (400kHz) compatible
- Power Down mode
- Internal VREF Circuit
- 3.0V / 1.8V VCC
- Package
- 57pin FBGA (5mm x 5mm)
- 48pin QFN (7.2mm x 7.2mm)



图1。AK8825方框图



图2。AK8825分量视频编码器方框图



图3。AK8825 NTSC/PAL复合视频编码器方框图



图4。高速视频DAC模式框图



图5。多模式分量视频编码器方框图



图6。525i/625i 模式方框图



图7。525P/625P 模式方框图



图8。1080i/720P模式方框图



图9。复合视频编码器方框图



图10。AK8825系统连接图

来源：AKM