请教仿真adc动态参数的matlab代码问题 懂的请来指点一下

parientfish

各位：       最近在研究仿真adc动态参数的matlab代码，其中一段如下所示：
%Find harmonic frequencies and power components in the FFT spectrum
%For this procedure to work, ensure the folded back high order harmonics do not overlap
%with DC or signal or lower order harmonics , so it should be modified according to the actual condition
for har_num=1:10
    tone=rem((har_num*(fin-1)+1)/numpt,1); %Input tones greater than fSAMPLE are aliased back into the spectrum
    if tone>0.5
        tone=1-tone; %Input tones greater than 0.5*Fsample (after aliasing) are reflected
    end
其作用应该是：高频的谐波分量会混叠到低频上，应该找出并保证其不会影响低频信号。但是该语句是怎样做到的？

fin是输入信号在功率谱中的位置(2932)，numpt是采样点数(8192)

期待您的回复！