A Novel Online Adaptive DC Offset Correcting Circuit

In this paper, a novel online adaptive DC (direct current) offset correction circuit which is used in the wireless receiver is proposed. Compared to the conventional methods, the proposed circuit adaptively corrects the DC offset to reduce the impact on the receiver performance. In the case of a large DC offset, the circuit employs a large tuning rate. On the contrary, when the incoming signal is with a small DC offset, the circuit employs a small tuning rate. Theocratical analysis and simulation results show that two advantages are gained with the proposed circuit. Firstly, the method can work online which adjusts slow-changing DC values because of operating conditions. Secondly, with the adaptive mechanism, the proposed circuit counteracts the DC offset with fast convergence speed but has little impact on the signal chain. Additional to the proposed circuit, an error analysis method is proposed. According to the proposed method, the circuit parameters are designed quickly and accurately.