摘要
TD-HSUPA由TD-SCDMA技术发展而来,其测试指标EVM为3G终端一致性测试的重要内容,测试过程中所恢复的参考信号精确度不高。一种减少直流偏量对测量信号影响的算法由此提出,使得TD-HSUPA EVM指标更为精确。该算法支持QPSK和16 QAM两种调制方式,避开了传统信号解调恢复参考信号的方式,提出了依次经过频差纠正、直流偏量纠正和初始相位纠正的过程来修正测量信号的方法。仿真结果表明,测试结果较为准确,耗时较短,满足3G终端EVM指标一致性测试的要求。
TD-HSUPA is developed from TD-SCDMA.Its indicator EVM is the important content of 3G terminal conformance tests,and the reference signal recovered from EVM test is not so accurate.An algorithm for removing DC offset from measured signals is proposed,thus to make EVM indicator for TD-HSUPA more accurate.The algorithm supports both QPSK and 16QAM modulation,and avoids the traditional recovery of reference signals by demodulating the measured signals.A method for correcting the measured signals sequentially by frequency offset correction,DC offset correction and the initial phase correction is given.Simulation results show that the test results are fairly accurate and the time-consuming is relatively short,thus satisfying the requirements of 3G terminal EVM indicator test.
出处
《通信技术》
2011年第6期67-69,共3页
Communications Technology
