ASTRO VG-876, Instruction Manual

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11
FUNCTIONS AVAILABLE WITH TV
STANDARD SIGNALS
11.1. Macrovision
11.1.1. Description and specifications
■ What is “Macrovision”?
Macrovision is a copy prevention system developed by ROVI Corporation (previously Macrovision
Corporation).
Widely used by video sources such as VHS and DVD-Video on the market and by satellite broadcasts, for
instance, the system ensures that, by causing the automatic gain control (AGC) of the video decks to
malfunction, users will not be able to record properly the video output sources which are protected by the
system.
The AGC circuit is designed to adjust the gain of the input signals automatically and maintain the appropriate
sensitivity, and almost all consumer-use VTRs now feature it. It serves to make dark images a little brighter
and excessively light images darker and keep them this way.
While keeping the luminance and chrominance signal components of the video signals unchanged,
Macrovision’s copy prevention signals cause the AGC to malfunction by mixing signals with non-standard
levels in the vertical blanking interval. This is why the brightness of the images will fluctuate even when the
images are recorded. These signals also have the effect of causing trouble for the sync signals and
disturbances in the images.
The trouble caused ensures that content is unwatchable even when it has been copied.
■
What does the “color stripe” function do?
This function is part of the Macrovision standard, and it provides color stripes to overlap with the regular
Macrovision signals.
It constitutes a method of superimposing the modulated color burst signal onto the video signals, and it is also
referred to as a means of color burst copy prevention.
The color stripe function inserts thin horizontal lines into the copied images and, like the Macrovision system, it
makes the images unwatchable.
* The color stripes are provided only in the Type 2 and 3 modes of the NTSC-M and J systems.
■
Macrovision specifications
Macrovision supports the TV signals of the following systems.
Its signals are superimposed onto the composite signals and Y/C signals.
• NTSC-M, NTSC-J, NTSC-443
• PAL, PAL-M, PAL-Nc
■
Notice
This product incorporates copyright protection technology that is protected by U.S. patents and
other intellectual property rights. Use of this copyright protection technology must be
authorized by ROVI Corporation, and is intended for commercial testing purposes only unless
otherwise authorized by ROVI. Reverse engineering or disassembly is prohibited.
・
Macrovision is an option. Contact ASTRODESIGN or your dealer.
• The Macrovision signals have different effects depending on the type of VHS
or DVD player. When using the system, please check the terms and
conditions of the agreement with ROVI Corporation.
Caution