下列运行后 , 单击窗体时显示的结果是 _______ 。 Private Sub Form_Click( Dim a As String, b As String, s As String a=”ABCDEFG”: b=”12345” S=Fn1(a)+ Fn1(b) Print Fn1(Fnl(Fn1(s))) End Sub Function Fn1(x As String) As String k= Len(x) Fn1= Mid(x, 2,k-2) End Function
【判断题】For AWGN channel, QPSK with Gray mapping can achieve the same bit error rate as a coherent BPSK in white Gaussian noise, but the bandwidth efficiency of BPSK is twice that of QPSK.
【单选题】About QPSK, the incorrect statement isa. The SER performance of QPSK in an ideal AWGN channel is equal to that of BPSKb. Each QPSK symbol corresponds to two bits.c. The spectrum efficiency of QPSK is ...
【多选题】For a given signal constellation, the average probability of symbol error incurred in maximum likelihood signal detection over an AWGN channel is invariant to the _________________ of the signal const...