adv7180 Analog Devices, Inc., adv7180 Datasheet - Page 22

• Manufacturer Part Number: adv7180
• Description: 10-bit, 4 X Oversampling Sdtv Video Decoder
• Manufacturer: Analog Devices, Inc.

ADV7180
VIDEO PROCESSOR
Figure 15 shows a block diagram of the ADV7180 video processor.
The ADV7180 can handle standard definition video in CVBS,
Y/C, 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:
•
•
•
•
•
•
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 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 Y/C separation.
AV Code Insertion.
At this point, the decoded luma (Y) signal is merged with
the retrieved chroma values. AV codes can be inserted
(as per ITU-R BT.656).
DIGITIZED Y (YC)
DIGITIZED C (YC)
DIGITIZED CVBS
DIGITIZED CVBS
CHROMA
STANDARD DEFINITION PROCESSOR
DIGITAL
DIGITAL
MACROVISION
CLAMP
CLAMP
LUMA
FINE
FINE
DETECTION
RECOVERY
CHROMA
DEMOD
F
SC
RECOVERY
VBI DATA
Figure 15. Block Diagram of the Video Processor
EXTRACT
CHROMA
FILTER
FILTER
LUMA
SYNC
AUTODETECTION
STANDARD
Rev. B | Page 22 of 112
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 employs a color subcarrier (F
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.
This block contains a chroma decimation filter (CAA) with
a fixed response and some shaping filters (CSH) that have
selectable responses.
Chroma Gain Control.
Automatic gain control (AGC) can operate on several
different modes, including gain based on the color subcarrier
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 2D, 5-line, superadaptive comb filter provides high
quality Y/C separation in case the input signal is CVBS.
CONTROL
2D COMB
CHROMA
2D COMB
LUMA
SLLC
INSERTION
CODE
AV
VIDEO DATA
OUTPUT
MEASUREMENT
BLOCK (≥ I
VIDEO DATA
PROCESSING
BLOCK
SC
) recovery unit to
2
C)