Toshiba TDP-D1 Service Manual page 81

Main Frame Introduction
This introduction provides detailed design information to assist in rapid development of a board
design and layout, and covers the following topics:
  A nalog RGB Interface
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  V ideo Interface
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  M icroprocessor Interface
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  I mageProcessor Interface
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  D isplay Interface
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  P ower Considera tions
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Analog RGB Interface
The first area of concern when using an Analog RGB Interface is the proper, clean,
non-interfering connection of DVI and analog RGB signals on the same circuit board. Second, with
these high-speed, low-amplitude interfaces, any power supply interference must be removed or
reduced as much as possible. Red, green, and blue analog data are typically received through a
15-pin "DIN" connector. This is carried over from the original computer-to-display interface systems
developed in the early 1970s. While the system worked well then, it was never intended for the
signals on today's graphics cards that operate at 160MHz with 2.7mV per grayscale level
performance. In addition, ESD and EMI considerations also influence interface decisions to improve
system reliability. The designers of this original interface did, however, consider cross-talk issues.
Therefore, care was taken to provide a separate signal ground pin for each signal pin whenever or
wherever possible. This fact must be remembered when laying out components.
Appendix B Circuit operation Theroy
80