| 摘要 |
PURPOSE: To prevent a space from being erroneously read as a mark by amplify ing a received signal when an absolute value is beyond a threshold voltage, otherwise, amplifying it at a different rate, and placing a threshold value be tween a size of a mark voltage and a space voltage level. CONSTITUTION: The values of resistors 26 and 30 decide the gain of an amplifier 10 for a signal beyond the threshold voltage of an 'S' interface. The values of the serial connection of resistors 24, 26, and 30 decide the gain of the amplifier 10 for a signal smaller than the threshold voltage. Thus, an amplifier which receives a signal through the 'S' interface for amplifying a voltage above or less than the threshold voltage(±VTHR) at a different rate, that is, amplifying a voltage having an absolute value beyond the threshold value, and attenuating a signal less than the threshold value is formed. Thus, it is possible to escape a 'space' from being erroneously identified as a 'mark'.
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