一种对数域电流模式积分器及其在高频滤波中的应用

提出了一种新颖的对数城电流模式积分器。该积分器的时间常数由参考偏置电流控制。用该积分器设计了二阶带通滤波器和0．1dB纹波三阶Chebyshev低通滤波器。计算机仿真表明，所设计的滤波器实际频响特性几乎是理想的，而且高频谐波失真很小，通频带灵敏度很低，频率在很宽的范围内可控。电路由双极型晶体管和接地电容构成，适合于全集成实现。

A Log-domain Current Mode Integrator and Its Applications in High Frequency Filtering

A novel log-domain current mode integrator is proposed. The integrator time constant is tunable by varying a reference bias current. By using the integrator, a second-order bandpass filter and a fifth-order Chebyshev lowpass filterwith 0. 1 dB ripples are designed. The simulation results demonstrate that the realfrequency responses of the proposed filters are nearly ideal,the Total Harmonic Distortion in high frequency and the passband sensitivity are very small and the cutofffrequency can be adjusted over a wide range. Also, the circuits are composed ofbipolar transistors and grounded capacitors which makes them suitable for fully-integrated circuit implementation.