Patent ID: 6664854
Filing Date: 2003-12-16
Classification: H03F,H03H

Abstract:
A base band filter for mobile communication including a semiconductor integrated circuit comprising:a plurality of electronic circuits, each of them having an input constituted by a single differential signal or a plurality of differential signals and an output of single phase, wherein input polarities of a first one of the plurality of electronic circuits and a second one of the plurality of electronic circuits are inverted, and an output terminal of the first electronic circuit and an output terminal of the second electronic circuit are connected to a circuit of the plurality of electronic circuits having a function of suppressing a common-mode signal component between the two terminals and amplifying a differential signal, wherein the circuit having the function is composed of a third one of the electronic circuits and a fourth one of the electronic circuits respectively having two input terminals, a first output terminal for receiving a signal provided by adding an output signal from the output terminal of the first electronic circuit and an output signal of the third electronic circuit, and a second output terminal for receiving a signal provided by adding an output signal from the output terminal of the second electronic circuit and an output signal of the fourth electronic circuit, and wherein the first output terminal is connected to one of input terminals of the third electronic circuit, the second output terminal is connected to other input terminal of the third electronic circuit and the second output terminal is connected to one of input terminals of the fourth electronic circuit and the first output terminal is connected to other input terminal of the fourth electronic circuit.