Patent ID: 8441313

Claim:
An analog baseband apparatus, comprising: a current-mode low-order filter, wherein an input impedance of the current-mode low-order filter is smaller than an output impedance thereof; a first current-mode programmable gain amplifier (PGA) unit, having an input terminal connected to an output terminal of the current-mode low-order filter; and a high-order filter, having an input terminal connected to an output terminal of the first current-mode PGA unit; wherein the first current-mode PGA unit comprises a current-mode amplifier, and the current-mode amplifier comprises: an input stage, having a first input terminal and a second input terminal respectively serving as a first input terminal and a second input terminal of the current-mode amplifier for receiving an input current, wherein the input stage generates an inner current according to the input current and a feedback current; an output stage, having a first input terminal and a second input terminal connected to the a first output terminal and a second output terminal of the input stage, and a first output terminal and a second output terminal respectively serving as output terminals of the current-mode amplifier; and a feedback circuit, connected to the input stage, for generating the feedback current according to the inner current of the input stage.