Patent ID: 6803867
Filing Date: 2004-10-12
Classification: H04B

Abstract:
A DC offset compensation circuit for a direct conversion receiver comprising a high-gain amplifier with an input terminal and an output terminal, with the output terminal of the amplifier connected to the input terminal of the direct conversion receiver, the circuit further comprising:a capacitor; an amplifier, comprising an input terminal and an output terminal, the input terminal of the amplifier connected to a one terminal of the capacitor and the output terminal of the direct conversion receiver, and the output terminal of the amplifier connected to the other terminal of the capacitor and the input terminal of the direct conversion receiver; and a switching circuit, connected in parallel to the capacitor and the amplifier; wherein, when the switching circuit is open, the capacitor and the amplifier comprise a combination circuit acting as a feedback circuit across the high-gain amplifier and generates a low cutoff frequency response to compensate a dynamic DC offset from the output terminal of the direct conversion receiver; and when the switching circuit is closed, a high cutoff frequency response compensates the static DC offset from the output terminal of the direct conversion receiver.