ADV7181 AD [Analog Devices], ADV7181 Datasheet - Page 3

• Manufacturer Part Number: ADV7181
• Description: Multiformat SDTV Video Decoder
• Manufacturer: AD [Analog Devices]

INTRODUCTION
The ADV7181B is a high quality, single chip, multiformat video
decoder that automatically detects and converts PAL, NTSC,
and SECAM standards in the form of composite, S-Video, and
component video into a digital ITU-R BT.656 format.
The advanced and highly flexible digital output interface enables
performance video decoding and conversion in line-locked
clock based systems. This makes the device ideally suited for a
broad range of applications with diverse analog video charac-
teristics, including tape based sources, broadcast sources,
security/surveillance cameras, and professional systems.
ANALOG FRONT END
The ADV7181B analog front end comprises three 9-bit ADCs
that digitize the analog video signal before applying it to the
standard definition processor. The analog front end employs
differential channels to each ADC to ensure high performance
in mixed-signal applications.
The front end also includes a 6-channel input mux that enables
multiple video signals to be applied to the ADV7181B. Current
and voltage clamps are positioned in front of each ADC to
ensure that the video signal remains within the range of the
converter. Fine clamping of the video signals is performed
downstream by digital fine clamping within the ADV7181B.
The ADCs are configured to run in 4× oversampling mode.
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STANDARD DEFINITION PROCESSOR
The ADV7181B is capable of decoding a large selection of
baseband video signals in composite, S-Video, and component
formats. The video standards supported by the ADV7181B
include PAL B/D/I/G/H, PAL60, PAL M, PAL N, PAL Nc, NTSC
M/J, NTSC 4.43, and SECAM B/D/G/K/L. The ADV7181B can
automatically detect the video standard and process it
accordingly.
The ADV7181B has a 5-line, superadaptive, 2D comb filter that
gives superior chrominance and luminance separation when
decoding a composite video signal. This highly adaptive filter
automatically adjusts its processing mode according to video
standard and signal quality with no user intervention required.
Video user controls such as brightness, contrast, saturation, and
hue are also available within the ADV7181B.
The ADV7181B implements a patented adaptive digital line-
length tracking (ADLLT) algorithm to track varying video line
lengths from sources such as a VCR. ADLLT enables the
ADV7181B to track and decode poor quality video sources such
as VCRs, noisy sources from tuner outputs, VCD players, and
camcorders. The ADV7181B contains a chroma transient
improvement (CTI) processor that sharpens the edge rate of
chroma transitions, resulting in sharper vertical transitions.
The ADV7181B can process a variety of VBI data services such
as closed captioning (CC), wide screen signaling (WSS), copy
generation management system (CGMS), EDTV, Gemstar
1×/2×, and extended data service (XDS). The ADV7181B is
fully Macrovision certified; detection circuitry enables Type I,
II, and III protection levels to be identified and reported to the
user. The decoder is also fully robust to all Macrovision signal
inputs.
ADV7181B