下行信号 meaning in English

downgoing signal

In pon , the transmission of downlink signal from olt to onu is not complex . usually , the information destined for onus are combined into a multiframe at olt via tdm before reaching the feeder fiber , and then broadcast to each onu via the passive optical demultiplexor . upon receiving the downlink multiframe signal , each onu takes out the part of information for itself only
在无源光网络中， olt到onu的下行信号的传输过程较为简单，一般在olt将需要发送到各onu的信息采用时分复用的方式组成复帧送到馈线光纤，通过无源光分路器以广播的方式发送到每一个onu ， onu收到下行复帧信号后分别取出属于自己的那一部分信息。