ADV7183BBSTZ Analog Devices Inc, ADV7183BBSTZ Datasheet - Page 27

• Manufacturer Part Number: ADV7183BBSTZ
• Description: IC,TV/VIDEO CIRCUIT,Color Decoder Circuit,CMOS,QFP,80PIN,PLASTIC
• Manufacturer: Analog Devices Inc
• Type: Video Decoderr

Specifications of ADV7183BBSTZ

• Applications: Projectors, Recorders, Security
• Voltage - Supply, Analog: 3.15 V ~ 3.45 V
• Voltage - Supply, Digital: 1.65 V ~ 2 V
• Mounting Type: Surface Mount
• Package / Case: 80-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Y-Shaping Filter
For input signals in CVBS format, the luma shaping filters play
an essential role in removing the chroma component from a
composite signal. Y/C separation must aim for best possible
crosstalk reduction while still retaining as much bandwidth
(especially on the luma component) as possible. High quality
Y/C separation can be achieved by using the internal comb
filters of the ADV7183B. Comb filtering, however, relies on the
frequency relationship of the luma component (multiples of the
video line rate) and the color subcarrier (F
CVBS signals, this relationship is known; the comb filter
algorithms can be used to separate out luma and chroma with
high accuracy.
For nonstandard video signals, the frequency relationship may
be disturbed, and the comb filters may not be able to optimally
remove all crosstalk artifacts without the assistance of the
shaping filter block.
An automatic mode is provided. The ADV7183B evaluates the
quality of the incoming video signal and selects the filter
responses in accordance with the signal quality and video
standard. YFSM, WYSFMOVR, and WYSFM allow the user to
manually override the automatic decisions in part or in full.
The luma shaping filter has three control registers:
•
•
•
YSFM[4:0] allows the user to manually select a shaping
filter mode (applied to all video signals) or to enable an
automatic selection (dependent on video quality and video
standard).
WYSFMOVR allows the user to manually override the
WYSFM decision.
WYSFM[4:0] allows the user to select a different shaping
filter mode for good quality CVBS, component (YPrPb),
and S-VHS (Y/C) input signals.
SC
). For good quality
Rev. B | Page 27 of 100
In automatic mode, the system preserves the maximum possible
bandwidth for good CVBS sources, since they can successfully
be combed, as well as for luma components of YPrPb and Y/C
sources, since they need not be combed. For poor quality
signals, the system selects from a set of proprietary shaping
filter responses that complements comb filter operation to
reduce visual artifacts.
The decisions of the control logic are shown in
YSFM[4:0] Y-Shaping Filter Mode, Address 0x17[4:0]
The Y shaping filter mode bits allow the user to select from a
wide range of low-pass and notch filters. When switched in
automatic mode, the filter is selected based on other register
selections (for example, detected video standard) as well as
properties extracted from the incoming video itself (for
example, quality, time-base stability). The automatic selection
always selects the widest possible bandwidth for the video input
encountered.
If the YSFM settings specify a filter (where YSFM is set to values
other than 00000 or 00001), the chosen filter is applied to all
video, regardless of its quality.
In automatic selection mode, the notch filters are used only for
bad quality video signals. For all other video signals, wideband
filters are used.
WYSFMOVR Wideband Y-Shaping Filter Override,
Address 0x18[7]
Setting the WYSFMOVR bit enables the use of the
WYSFM[4:0] settings for good quality video signals. For more
information, refer to the general discussion of the luma shaping
filters in the
in
When WYSFMOVR is 0, the shaping filter for good quality
video signals is selected automatically.
Setting WYSFMOVR to 1 enables manual override via
WYSFM[4:0] (default).
F igure 11.
1 7 8 H
Y -Shaping Filter section and the flowchart shown
1 7 7 H
F igure 11.
1 7 6 H
ADV7183B