| 摘要 |
PURPOSE:To realize an extraction of only the noise component out of the signal, by connecting a capacitor between the output of the low-impedance circuit and the pressure dividing point of the pressure dividing circuit and then keeping the terminal voltage of the capacitor at a constant level by the power source having the same voltage as the pressure dividing point. CONSTITUTION:The envelope curve detection output (a) of the signal input is converted into the low-output impedance via the low-impedance circuit LZ to be applied to the capacitor C4. And at the same time, the switches SW1 and SW2 are turned on only for the period of the differential pulse (b) produced by the differentiating circuit DF1 and DF2 each. The capacitor C4 is connected to the pressure dividing point of the pressure dividing circuit as well as to the power sources E1 and E2 having the same voltage as the pressure dividing point and via the switches SW1 and SW2. And the capacitor C4 is charged or discharged quickly by the power source E1 or E2 every time the level of the output (a) varies,and thus keeps a con stant voltage level. At the same time, the noise component passes through the capacitor C4 in the form of the AC signal. And thus only the noise component is delivered. |
