| 摘要 |
PURPOSE:To use a resistance to an impedance element which is used in common to the input and the output and as a result to use just one switch, by connecting a signal output terminal to the resistance, grounding the junction of the output terminal and the resistance via the switch and connecting the other end of the resistance to a signal input/output terminal and an input terminal. CONSTITUTION:An end of a switch 21 is connected to a resistance 16, and the other end of the switch 21 is grounded. When this switch 21 is turned off, the signal of the signal output terminal 13 of an information device 12 is delivered to a signal input/output terminal 17 through an amplifier 14, a capacitor 15 and a resistance 16. When the switch 21 is turned on, the signal fed to the terminal 17 is applied to a signal input terminal 20 through a capacitor 18 and an amplifier 19. In such way, the resistance 16 is used as both the input impedance and the output impedance. Furthermore the switch 21 sufficies with a transistor or a mechanical switch. |
