A Fast and Precise Blind I/Q Mismatch Compensation for Image Rejection in Direct-Conversion Receiver

作者：Kim Suna^*; Yoon Dae Young; Park Hyung Chul; Yoon Giwan; Lee Sang Gug

来源：ETRI Journal, 2014, 36(1): 12-21.

DOI：10.4218/etrij.13.0113.0320

• Image rejection
• l/Q gain mismatch
• l/Q phase mismatch
• DC offset
• direct-conversion receiver
• DCR
• low-IF
• zero-IF
• LMS algorithm
• adaptive step size

In this paper, we propose a new digital blind inphase/quadrature-phase (I/Q) mismatch compensation technique for image rejection in a direct-conversion receiver (DCR). The proposed image-rejection circuit adopts DC offset cancellation and a sign-sign least mean squares (LMS) algorithm with a unique step size adaptation both for a fast and precise I/Q mismatch estimation. In addition, several performance-optimizing design considerations related to accuracy, speed, and hardware simplicity are discussed. The implementation of the proposed circuit in an FPGA results in an image-rejection ratio (IRR) of 65 dB, which is the best performance with modulated signals, along with an adaptation time of 0.9 seconds, which is a tenfold increase in the compensation speed as compared to previously reported circuits. The proposed technique will be a promising solution in the area of image rejection to increase both the speed and accuracy of future DCRs.

• 出版日期2014-2