ADV7189 datasheet(21/104 Pages) AD

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ADV7189

Rev. A | Page 21 of 104

STANDARD DEFINITION PROCESSOR (SDP)

DIGITIZED CVBS

DIGITIZED Y (YC)

VIDEO DATA

OUTPUT

STANDARD DEFINITION PROCESSOR

DIGITIZED CVBS

DIGITIZED C (YC)

MACROVISION

DETECTION

VBI DATA

RECOVERY

STANDARD

AUTODETECTION

LUMA

FILTER

LUMA

DIGITAL

FINE

CLAMP

GAIN

CONTROL

LUMA

RESAMPLE

LUMA

2D COMB

SLLC

CONTROL

CHROMA

FILTER

CHROMA

DEMOD

FSC

RECOVERY

CHROMA

DIGITAL

FINE

CLAMP

GAIN

CONTROL

CHROMA

RESAMPLE

CHROMA

2D COMB

SYNC

EXTRACT

LINE

LENGTH

PREDICTOR

RESAMPLE

CONTROL

CODE

INSERTION

MEASUREMENT

BLOCK (= >12C)

VIDEO DATA

PROCESSING

BLOCK

Figure 8. Block Diagram of the Standard Definition Processor

A block diagram of the ADV7189’s standard definition

processor (SDP) is shown in Figure 8.

The SDP block can handle standard definition video in CVBS,

YC, and YPrPb formats. It can be divided into a luminance and

chrominance path. If the input video is of a composite type

(CVBS), both processing paths are fed with the CVBS input.

SD LUMA PATH

The input signal is processed by the following blocks:

•

Digital Fine Clamp. This block uses a high precision

algorithm to clamp the video signal.

•

Luma Filter Block. This block contains a luma decimation

filter (YAA) with a fixed response, and some shaping filters

(YSH) that have selectable responses.

•

Luma Gain Control. The automatic gain control (AGC) can

operate on a variety of different modes, including gain

based on the depth of the horizontal sync pulse, peak white

mode, and fixed manual gain.

•

Luma Resample. To correct for line-length errors as well as

dynamic line-length changes, the data is digitally

resampled.

•

Luma 2D Comb. The two-dimensional comb filter provides

YC separation.

•

AV Code Insertion. At this point, the decoded luma (Y)

signal is merged with the retrieved chroma values. AV

codes (as per ITU-R. BT-656) can be inserted.

SD CHROMA PATH

The input signal is processed by the following blocks:

•

Digital Fine Clamp. This block uses a high precision algo-

rithm to clamp the video signal.

•

Chroma Demodulation. This block employs a color sub-

carrier (Fsc) recovery unit to regenerate the color

subcarrier for any modulated chroma scheme. The

demodulation block then performs an AM demodulation

for PAL and NTSC and an FM demodulation for SECAM.

•

Chroma Filter Block. This block contains a chroma

decimation filter (CAA) with a fixed response, and some

shaping filters (CSH) that have selectable responses.

•

Gain Control. Automatic gain control (AGC) can operate

on several different modes, including gain based on the

color subcarrier’s amplitude, gain based on the depth of the

horizontal sync pulse on the Luma channel, or fixed

manual gain.

•

Chroma Resample. The chroma data is digitally resampled

to keep it perfectly aligned with the luma data. The

resampling is done to correct for static and dynamic line-

length errors of the incoming video signal.

•

Chroma 2D Comb. The two-dimensional, 5-line,

superadaptive comb filter provides high quality YC

separation in case the input signal is CVBS.

•

AV Code Insertion. At this point, the demodulated chroma

(Cr and Cb) signal is merged with the retrieved luma

values. AV codes (as per ITU-R. BT-656) can be inserted.

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