ADV7181B
Rev. B | Page 4 of 100
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 uses
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 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.
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
standards 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 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 close 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,
Type II, and Type III protection levels to be identified and
reported to the user. The decoder is also fully robust to all
Macrovision signal inputs.
