A discrete-time channel-selection filter with flat passband characteristic for LTE

A discrete-time channel-selection filter with flat passband characteristic that satisfies the LTE specification is proposed. To improve the flatness in passband, a second order IIR filter and a compensation filter are adopted. High stopband attenuation is achieved by using the moving average filters. Through the control of sampling frequency, the proposed discrete-time filter chain satisfies the required specifications for all the channels in LTE. The filter is implemented using TSMC 65-nm CMOS process. The simulation shows that proposed discrete-time filter chain has flatness degradation lower than about 4 dB at passband edge.