【摘要】 提出了一种适用于ITU-T J.83B的载波同步与自适应均衡的联合设计方案。系统首先采用常模数算法进行盲均衡,然后启动载波同步环路。环路通过先后采用极性判决算法和判决指示算法,起到了短时间大范围鉴频和降低相位方差的作用。载波恢复后,均衡器切换到最小均方差算法,使得系统获得最佳的调制误差比。依据提出的一套适合算法设计和硬件开发的验证方法,整个设计方案先后通过各级验证,并最终在硬件测试平台上得到测试。针对64QAM和256QAM信号,当信噪比分别达到27 dB和33 dB时,解调器的误比特率可小于10?4。验证结果表明该设计方案性能优良并具备可行性。更多还原

【Abstract】 A joint design of adaptive equalizer and carrier recovery loop was presented for ITU-T J.83B.The whole system initially operated in CMA mode to compensate the channel distortion.When the channel eye was opened,the carrier recovery loop was started.The loop firstly operated in polarity decision algorithm to capture the frequency offset.Then decision direct algorithm was used for decreasing the phase jitter.Finally,the system switched to least mean square mode to improve the MER.A verification method was proposed for algorithm and hardware design.At last,the whole design was tested in the test-platform.The pre-FEC system can achieve the BER equal to 10?4 when operat-ing at SNR=27 dB for 64QAM and SNR=33 dB for 256 QAM.更多还原