| 摘要 |
A noise eliminating circuit is provided for a graphical input terminal having an input unit which generates electrical signals when a stylus is used to write on a surface of the unit. The electrical signals correspond to information written on the surface. Further, an envelope signal is generated responsive to the starting of the writing, which continues throughout the writing, and ends at the time when the writing stops on the surface. A low-pass filter responds to the electrical signals representing the written message to remove high frequency noise therefrom. A switch selects either the electrical signals or the output of the low-pass filter as the output signal to the noise eliminating circuit. The switch is operated in response to the envelope signal specifying the starting and stopping times.
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