![](https://lstatic.shangxueba.com/sxbzda/h5/images/m_q_title.png)
[多选题]
NR系统中下行物理信号有哪些?()
A.辅同步信号(Secondary synchronization signal,SSS)
B.信道状态信息参考信号(Channel-state information reference signal,CSI-RS)
C.解调参考信号(Demodulation reference signals,DM-RS)
D.相位跟踪参考信号(Phase-tracking reference signals,PT-RS)
E.主同步信号(Primary synchronization signal,PSS)
![](https://lstatic.shangxueba.com/sxbzda/h5/images/tips_org.png)