A. Calling you, Roger?
B. Is the frequency in use?
C. Is any body in the frequency?
D. Any body here?
A.RTTY
B. CW
C. PSK31
D. SSTV
A、OFDM(Orthogonal Frequency Division Multiplexing)把系统带宽分成多个的相互正交的子载波,在多个子载波上并行数据传输
B、OFDM本质是频率复用
C、OFDM通过子载波之间的正交,大大地提升了频谱效率
D、OFDM采用多载波(称为子载波)来传送信息流,可以看作是多载波传送技术
A.Change of timeslot only
B.Change of frequency only
C.Change of timeslot and/or change of frequency
A.Gain of both frequency diversity and interference diversity
B.Gain of frequency diversity only
C.Gain of interference diversity only
D.Neither gain of frequency diversity nor gain of interference diversity
A.4*3
B.7*3
C.1*3
D.MRP