The open loop transmit diversity scheme, named as STTD, and two feedback close loop transmit diversity schemas in downlink channel communication was defined in WCDMA standard.

WCDMA标准在下行信道传输中采用了称作STTD的开环发射分集方案和两种反馈模式的闭环发射分集方案。

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Based on the analysis to close loop hydraulic system of hydraulic hammer, this paper provides on open loop hydraulic system.

本文对液压锤使用的闭式液压系统性能进行了分析，在此基础上提出了泵直接传动的开式液压系统。

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With the help of the method, the control accuracy similar to that of close loop system can be obtained and the system has the same stability as that of open loop system.

采用这种控制方式，可以获得类似闭环系统的控制精度和开环系统的稳定性。

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