共查询到17条相似文献,搜索用时 296 毫秒
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QAM接收机定时抖动问题的研究 总被引:1,自引:0,他引:1
定时抖动是QAM接收机定时同步的重要性能指标,对两种减小定时抖动的方法进行了分析,第一种是改进的Gardner算法,另一种是在定时环路中插入环路预滤波器的方法。通过对以上两种方法的研究和对比,二者都能减小环路的定时抖动,但二者在性能和资源消耗上有一定区别,实际应用中根据系统的要求做出选择。 相似文献
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全数字接收机平方定时恢复环路 总被引:1,自引:0,他引:1
本文着重研究全数字接收机中定时恢复环路的设计.该环路由内插滤波器,预滤波器,平方定时误差检测,环路滤波和定时控制单元组成,仿真结果表明.通过预滤波明显减小了定时抖动,该算法可以达到较好的性能,井由单片FPGA实现,该芯片已成功用于QM全数字接收机中。 相似文献
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The evolving digital television broadcasting standard does not standardize the data rate 1/T of the transmitted data but instead leaves it completely unspecified. We propose two digital receiver algorithms based on a free running oscillator (rate 1/Ts) for the processing of an extended range of variable sample rates Ts/T based on a timing synchronization algorithm producing synchronized samples at rate M/T where M is variable. It is shown that the well known timing error detector from Gardner[1] also works for M>2 which forms the basis of the timing synchronizer which is built similar to [2, 3]. Main issue for variable symbol rate receivers is to supress aliasing due to the different sampling rates in the receiver. One of the algorithms removes aliasing by filtering the received samples prior to timing synchronization and choosing M=2, whereas the second algorithm also uses the sample rate 3/T in the timing recovery loop and matched filter depending on T/Ts and thus avoids the necessity of prefiltering. The algorithms are compared in terms of their complexity, timing error variance and BER performance. Both algorithms can be implemented causing negligible loss in a DVB receiver. 相似文献
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模拟下变频或基于多相滤波的数字正交变换都可能会在IQ路之间引入一个固定的分数倍采样点的延时,本文提出一种分数延时校正和符号定时同步相结合的方案,使两种误差在同一个环路中得到解决,符号定时同步环路采用Gardner时钟误差鉴相算法和拉格朗日内插算法,方案在1024QAM解调系统中验证成功。 相似文献