| 摘要 |
PURPOSE:To prevent unnecessary radiation from being emitted on a logic IC by a method wherein a integrating circuit consisting of a resistor and a capacitor is provided in the logic IC to make the time constant of the circuit variable. CONSTITUTION:Control terminals A8 and B9 are both turned to an 'L' level in a mode 1 and switches SW1(12)-SW3(14) are controlled ON, OFF and OFF by a control circuit 15. As a result, a resistor 6 is short-circuited, capacitors C1(10) and C2(11) are opened; integrating circuit comes to a state equal to its absence in the mode 1 and the time constant of the circuit becomes 0; that is, the operation of the circuit becomes the same as that of a general logic IC. The output waveform to a rectangular input wave at this time includes a high-frequency component. Then, turning the terminal B9 to an 'H' level in a mode 2 makes the resistor 6 and the capacitor C1(10) effective and the integrating circuit alive; the high-frequency component is some removed from the output waveform. The high-frequency component is further removed in modes 3 and 4. |
