ADV7181D View Datasheet(PDF) - Analog Devices

Part Name

Description

Manufacturer

ADV7181D

10-Bit, 10-Channel, Multiformat SDTV/HDTV Video Decoder and RGB Graphics Digitizer

Analog Devices 

ADV7181D

DETAILED DESCRIPTIONS

ANALOG FRONT END

The ADV7181D analog front end comprises four 10-bit ADCs

that digitize the analog video signal before applying it to the SDP

or CP. The analog front end uses differential channels to each

ADC to ensure high performance in a mixed-signal application.

The front end also includes a 10-channel input mux that enables

multiple video signals to be applied to the ADV7181D. Current

and voltage clamps are positioned in front of each ADC to ensure

that the video signal remains within the range of the converter.

Fine clamping of the video signals is performed downstream by

digital fine clamping in either the CP or SDP.

Optional antialiasing filters are positioned in front of each ADC.

These filters can be used to band-limit standard definition video

signals, removing spurious out-of-band noise.

The ADCs are configured to run in 4× oversampling mode

when decoding composite and S-Video inputs; 2× oversampling

is performed for component 525i, 625i, 525p, and 625p sources.

All other video standards are 1× oversampled. Oversampling

the video signals reduces the cost and complexity of external

antialiasing filters with the benefit of an increased signal-to-

noise ratio (SNR).

The ADV7181D can support simultaneous processing of CVBS

and RGB standard definition signals to enable SCART compati-

bility and overlay functionality. A combination of CVBS and

RGB inputs can be mixed and output under the control of the

I2C registers and the fast blank (FB) pin.

STANDARD DEFINITION PROCESSOR (SDP)

The SDP section is capable of decoding a large selection of

baseband video signals in composite, S-Video, and YUV

formats. The video standards supported by the SDP include

PAL B/D/I/G/H, PAL60, PAL M, PAL N, NTSC M/J, NTSC 4.43,

and SECAM B/D/G/K/L. The ADV7181D automatically detects

the video standard and processes it accordingly.

The SDP has a five-line, superadaptive, 2D comb filter that pro-

vides superior chrominance and luminance separation when

decoding a composite video signal. This highly adaptive filter

automatically adjusts its processing mode according to video

standards and signal quality with no user intervention required.

The SDP has an IF filter block that compensates for attenuation

in the high frequency luma spectrum due to the tuner SAW filter.

The SDP has specific luminance and chrominance parameter

control for brightness, contrast, saturation, and hue.

The ADV7181D implements a patented ADLLT algorithm to

track varying video line lengths from sources such as a VCR.

ADLLT enables the ADV7181D to track and decode poor

quality video sources such as VCRs, noisy sources from tuner

outputs, VCD players, and camcorders.

Data Sheet

The SDP also contains a chroma transient improvement (CTI)

processor. This processor increases the edge rate on chroma

transitions, resulting in a sharper video image.

The SDP can process a variety of VBI data services, such as tele-

text, closed captioning (CC), wide screen signaling (WSS), video

programming system (VPS), vertical interval time codes (VITC),

copy generation management system (CGMS), GemStar 1×/2×,

and extended data service (XDS). The ADV7181D SDP section has

a Macrovision 7.1 detection circuit that allows it to detect Type I,

Type II, and Type III protection levels. The decoder is also fully

robust to all Macrovision signal inputs.

COMPONENT PROCESSOR (CP)

The CP section is capable of decoding and digitizing a wide range

of component video formats in any color space. Component video

standards supported by the CP are 525i, 625i, 525p, 625p, 720p,

1080i, graphics up to XGA at 70 Hz, and many other standards.

The CP section of the ADV7181D contains an AGC block.

When no embedded synchronization is present, the video

gain can be set manually. The AGC section is followed by a

digital clamp circuit, which ensures that the video signal is

clamped to the correct blanking level. Automatic adjustments

within the CP include gain (contrast) and offset (brightness);

manual adjustment controls are also supported.

A fixed mode graphics RGB to component output is available.

A color space conversion matrix is placed between the analog

front end and the CP section. This enables YCrCb-to-DDR RGB

and RGB-to-YCrCb conversions. Many other standards of color

space can be implemented using the color space converter.

The output section of the CP is highly flexible. It can be config-

ured in SDR mode with one data packet per clock cycle or in

DDR mode where data is presented on the rising and falling

edges of the clock. In SDR and DDR modes, HS/CS, VS, and

FIELD/DE (where applicable) timing reference signals are

provided. In SDR mode, a 20-bit 4:2:2 is possible. In DDR

mode, the ADV7181D can be configured in an 8-bit or 10-bit

4:2:2 YCrCb or in a 12-bit 4:4:4 RGB pixel output interface with

corresponding timing signals.

The CP section contains circuitry to enable the detection of

Macrovision encoded YPrPb signals for 525i, 625i, 525p, and

625p. It is designed to be fully robust when decoding these

types of signals.

VBI extraction of component data is performed by the CP

section of the ADV7181D for interlaced, progressive, and high

definition scanning rates. The data extracted can be read back

over the I2C interface.

Rev. 0 | Page 14 of 24

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