| 摘要 |
PURPOSE:To change the attenuation stepwise, by connecting a resistive element between an input and an output terminal, constituting a unit attenuator through the connection of a pair of common terminals of a single pole double throw switch to the output terminal, and cascade-connecting a pluality of the unit attenuators. CONSTITUTION:In selecting a common terminal (c) of a single pole double throw switch to a fixed terminal (a), a signal flows in the route of an input terminal 1, the fixed terminal (a), the common terminal (c) and an output terminal 2. Thus, a resistive element 3 is short-circuited and no signal is attenuated at this unit attenuator 11. Inversely, in selecting the common terminal (c) to be connected to a fixed terminal (b), an inverse-L type resistance attenuator of 1 dB can be constituted. In other unit attenuators 12-14, through the operation of the single pole double throw switch, the control for the specified attenuation can be performed. Thus, through the operation of the unit attenuators 11-14, the attenuation can be switch in the step of 1 dB between 0 dB and 15 dB. |
