OFDM通信系统与QPSK系统性能比较(18)

plot(f1,abs(z1),'r--'); xlabel('f');ylabel('幅度谱'); legend('原信号'); N=64;

fs=10240000/2; % Symbol rate df = fs/N; f2 = 0:df:(N-1)*df; y2=ich+qch*i; z2 = fft(y2,N); figure;

plot(f2,abs(z2),'r--'); xlabel('f');ylabel('幅度谱'); legend('QPSK后的信号');

N=fftlen2;

fs=10240000/2/64; % Symbol rate df = fs/N; f3 = 0:df:(N-1)*df; y3=ich3+qch3*i; z3 = fft(y3,N); figure;

plot(f3,abs(z3),'r--'); xlabel('f');ylabel('幅度谱'); legend('OFDM后的信号');