| 摘要 |
PURPOSE:To improve the isolation performance of an output signal, by providing a means which performs the ON/OFF control of plural switching devices and also controls the supplying of a bias voltage from a bias supplying means to a buffer circuit responding to the switching and selecting operation of an analog switch. CONSTITUTION:The titled circuit is constituted in such a way that plural switching devices inserted between each buffer circuit 4 and the analog switch 5, and the means which controls whether the bias voltage from the bias supplying means should be supplied or not to each buffer circuit corresponding to the switching and selecting operation of the analog switch 5 and controls the switching devices, are provided, and an unrequired signal component from a non-selected system is suppressed. By interposing the switching device 5 to the buffer circuit 4 in series, the switching device 5 functions as a capacitor small in capacity even when the unrequired signal component from a non- selected signal path leaks out via the buffer circuit 4, therefore, it is possible to damp the unrequired signal component than ever, and to select and output the signal with superior isolation.
|
