ADV7180
VIDEO PROCESSOR
STANDARD DEFINITION PROCESSOR
MACROVISION
DETECTION
VBI DATA
RECOVERY
STANDARD
AUTODETECTION
SLLC
CONTROL
DIGITIZED CVBS
DIGITIZED Y (YC)
LUMA
DIGITAL
FINE
CLAMP
LUMA
FILTER
LUMA
GAIN
CONTROL
LUMA
RESAMPLE
LUMA
2D COMB
SYNC
EXTRACT
LINE
LENGTH
PREDICTOR
RESAMPLE
CONTROL
AV
CODE
INSERTION
VIDEO DATA
OUTPUT
DIGITIZED CVBS
DIGITIZED C (YC)
CHROMA
DIGITAL
FINE
CLAMP
CHROMA
DEMOD
CHROMA
FILTER
CHROMA
GAIN
CONTROL
CHROMA
RESAMPLE
CHROMA
2D COMB
MEASUREMENT
BLOCK (≥ I
2
C)
VIDEO DATA
PROCESSING
BLOCK
05700-015
F
SC
RECOVERY
Figure 15. Block Diagram of the 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 CHROMA PATH
The input signal is processed by the following blocks:
•
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
SC
) 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.
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.
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).
•
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Rev. A | Page 22 of 112
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