| 摘要 |
An apparatus having various on-screen display (OSD) functions and methods for each function are provided. The apparatus includes an on-screen display device for receiving serial data having a RAM write address, a ROM address, and the on-screen display functions. The apparatus synthesizes a character signal corresponding to serial data with a background color signal or an external composite video signal in response to an internal or external composite synchronous signal and provides the result to a monitor. The apparatus also includes a synchronous signal generating device for generating internal horizontal and vertical synchronous signals upon receiving a main clock signal, synthesizing means for synthesizing an internal equalization pulse with the internal horizontal and vertical synchronous signals, and means for determining the internal composite synchronous signal or the external composite synchronous signal extracted from the composite video signal. A control device is also part of the OSD apparatus. The control device outputs user serial data to the on-screen display device, generates the main clock signal from a system clock, and controls the on-screen display device and the synchronous signal generating device.
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