华为CDMA2000采用QPSK调制技术

QPSK调制 1.2288Mcps: 短码码片速率 . 当同一载频的所有的信道扩频后，采用QPSK调制，并转换为模拟信号，混合之后经过射频调制发射 CDMA 核心技术 I Q I channel PN sequence 1.2288Mcps Q channel PN sequence 1.2288Mcps Baseband filter Baseband filter Cos(2pfct) Sin(2pfct) I(t) Q(t) s(t) A In an actual application, the system implements the modulation in this way: as shown above, I and Q channel sequences in the figure represent two channels of cyclic PN short code sequences. The cyclic period of each channel of PN short codes is 215. For different sectors, there are different starting locations of I and Q sequence cycles (that is to say, different sectors have different time offsets). In this way, different PN short code sequences can be obtained and a mobile station can recognize the information from different sectors.