| 摘要 |
PURPOSE:To analyse a circuit easily and to set up and adjust a constant easily by coupling a passive filter enabled to change the constant by an active filter having a basic frequency characteristic by a switching means. CONSTITUTION:The active filter consisting of an inversional amplifier 17, a capacitor 18 and a resistor 19 is coupled in series with the passive filter consisting of resistors 11, 12, 14, 15 and a capacitor 13 to form a filter circuit. The basic characteristics of the filter circuit is fixed by the time constants of the resistors 19 and capacitor 18 of the active filter. The time constant due to the capacitor 13 and the resistors 11, 12, 14, 15 is changed by turning a switch 16 to compensate the characteristics. |
