一种应用于QAM信号的新型高速均衡器

提出了一种基于新型算法SGLMS-CMA的高速QAM均衡器.SGLMS-CMA算法在stop-and-go原理指导下结合了经典CMA算法和DD-LMS算法.MATLAB仿真表明,与经典CMA算法相比,新型算法具有收敛速度快5倍,剩余MSE改善3～5dB,运算复杂度减少了82%,可纠正残留相偏的优点.综合结果表明,采用SGLMS-CMA+DD-LMS的新型均衡器与CMA+DD-LMS均衡器相比,系统中均衡器模块的硬件开销只增加5%.最后使用SMIC 0.18μm工艺库对新型均衡器进行综合,并且嵌入到QAM解调芯片中进行流片,最终测试结果表明新型均衡器性能优越.

A Novel High-Speed Equalizer for QAM Signals

A high-speed equalizer based on a new algorithm: stop-and-go-DD-LMS CMA (SGLMS-CMA) for quadrature amplitude modulation (QAM) signals is presented. It integrates conventional constant modulus algorithm (CMA) and decision-direct least-mean-square (DD-LMS) under stop-and-go principle. Matlab simulations indicate that, compared with conventional CMA,the new algorithm performs five times faster in convergence speed, 3～5dB improved in rudimental mean square error (MSE), 82% decreased in operation complexity and can correct a final phase ambiguity. As to the equalizer block in the system,synthesis results show that the SGLMS-CMA + DD-LMS equalizer's hardware consumption is only 5% greater than the CMA + DD-LMS equalizer's. Finally by using SMIC 0.18μm library to synthesis, the new equalizer is embedded into QAM demodulation chip,and test results show that the new equalizer acts better.