adv7188 Analog Devices, Inc., adv7188 Datasheet - Page 24

• Manufacturer Part Number: adv7188
• Description: Multiformat Sdtv Video Decoder With Fast Switch Overlay Support
• Manufacturer: Analog Devices, Inc.

ADV7188
STANDARD DEFINITION PROCESSOR (SDP)
A block diagram of the ADV7188 standard definition processor
(SDP) is shown in Figure 12.
The SDP can handle standard definition video in CVBS, Y/C,
and YPrPb formats. It can be divided into a luminance path and
a 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:
•
•
•
•
•
•
Luma Digital Fine Clamp. This block uses a high precision
algorithm to clamp the video signal.
Luma Filter. This block contains a luma decimation filter
(YAA) with a fixed response and some luma-shaping filters
(YSH) that have selectable responses.
Luma Gain Control. The automatic gain control (AGC) can
operate on a variety of modes, including a mode based on
the depth of the horizontal sync pulse, a mode based on the
peak white mode, and a mode that uses a fixed manual gain.
Luma Resample. To correct for errors and dynamic changes
in line lengths, the data is digitally resampled.
Luma 2D Comb. The two-dimensional comb filter provides
Y/C 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.
DIGITIZED C (Y/C)
DIGITIZED Y (Y/C)
DIGITIZED CVBS
DIGITIZED CVBS
CHROMA
STANDARD DEFINITION PROCESSOR
DIGITAL
DIGITAL
CLAMP
CLAMP
MACROVISION
LUMA
FINE
FINE
DETECTION
RECOVERY
CHROMA
DEMOD
F
SC
Figure 12. Block Diagram of the Standard Definition Processor
RECOVERY
VBI DATA
EXTRACT
CHROMA
FILTER
FILTER
LUMA
SYNC
AUTODETECTION
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STANDARD
PREDICTOR
CONTROL
CONTROL
CHROMA
LENGTH
LUMA
GAIN
GAIN
LINE
SD CHROMA PATH
The input signal is processed by the following blocks:
•
•
•
•
•
•
•
RESAMPLE
RESAMPLE
RESAMPLE
CONTROL
CHROMA
LUMA
Chroma Digital Fine Clamp. This block uses a high
precision algorithm to clamp the video signal.
Chroma Demodulation. This block uses a color subcarrier
(F
any modulated chroma scheme and then performs an AM
demodulation for PAL and NTSC and an FM demodulation
for SECAM.
Chroma Filter. This block contains a chroma decimation
filter (CAA) with a fixed response and some chroma-
shaping filters (CSH) that have selectable responses.
Chroma Gain Control. Automatic gain control (AGC) can
operate on several modes, including a mode based on the
color subcarrier’s amplitude, a mode based on the depth of
the horizontal sync pulse on the luma channel, and a mode
that uses a fixed manual gain.
Chroma Resample. The chroma data is digitally resampled
to keep it aligned with the luma data. The resampling is done
to correct for static and dynamic errors in the line lengths
of the incoming video signal.
Chroma 2D Comb. The two-dimensional, 5-line, super-
adaptive comb filter provides high quality Y/C 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.
SC
) recovery unit to regenerate the color subcarrier for
CONTROL
2D COMB
CHROMA
2D COMB
LUMA
SLLC
INSERTION
CODE
AV
VIDEO DATA
OUTPUT
MEASUREMENT
BLOCK (= >I
VIDEO DATA
PROCESSING
BLOCK
2
C)