%figure;
fc = 50e9;
Stx = transmitter_TR_TH_2PPM;
N = length(Stx);
L = 100;%%%%%%%%L越大，PSD方差越小
M = N/L;
P = zeros(1,M);
%計算每段數(shù)據(jù)功率譜
for i=1:L
    si = Stx((i-1)*M+1:i*M);%第i段數(shù)據(jù)功率譜
    Si = fft(si,M);%%%FFT
    Pi = (abs(Si)).^2/M;
    P = P+Pi;
end

P = P/L;
%橫坐標(biāo)，赫茲；縱坐標(biāo)，dB
t = 0:round(M/2-1);
k = t*fc/M;
P_dB = 10*log10(P(t+1));
plot(k,P_dB);
xlabel('頻率 /Hz'),ylabel('功率譜 /dBW'),title('TR-PPM PSD');
%grid;