Patent ID: 6720850
Filing Date: 2004-04-13
Classification: H03H,H03K

Abstract:
A variable attenuator comprising:a FET; an inductive element connected to one of the source and the drain of the FET thereby forming a series connection of the inductive element and the FET; a capacitive element connected in parallel with the series connection of the inductive element and the FET; a first terminal and a second terminal respectively connected to both ends of the capacitive element; an attenuation setting unit which variably sets an amount of attenuation to a signal flowing between the first terminal and the second terminal by varying a voltage difference between the gate of the FET and one of the source and drain; and a constant potential connected to the gate of the FET, wherein the attenuation setting unit is a variable-voltage generator which is connected to the source or drain of the FET to variably set the source or drain voltage of the FET.