Analysis and Design of M-Channel Hybrid Filter Bank With Digital Calibration

Hybrid filter bank (HFB) is widely used in frequency-interleaved analog-to-digital converters, but traditional HFB structures suffer various degrees of imperfections. This paper presents a new-structure HFB based on power complementary pair. The proposed architecture only needs M-1 analog analysis filters in M-channel frequency-interleaved analog-to-digital converters, and the analog analysis filters can satisfy the pairwise power complementary property. Therefore, the new structure simplifies analog circuits to a larger extent compared with traditional structure. Based on the proposed structure, an estimation algorithm is put forward to estimate the channel mismatch errors and filter bank mismatch errors. Accordingly, calibration is carried out in digital domain. Experiments are performed on the basis of designing a fourchannel 20 GS/s 12-bit frequency-interleaved analog-to-digital converter system, and the simulation results prove the effectiveness of the proposed method. Average distortion error of -6.8192 x 10-10 dB and an average aliasing error of -104.84dB can be achieved after calibration, and resolution of this architecture can be up to 14 bit.