
Re: how remove unwanted high frequencies in MATLAB?
Posted:
Apr 22, 2013 9:03 PM


On Tuesday, April 23, 2013 10:59:08 AM UTC+12, ghasem wrote: > > Well, when you do the Fourier Series summation, just leave out the components with frequencies greater than f1. > > ========================== > > exactly,my problem is here.I want to remove frequencies higher than f1,but I don't know how code it in MATLAB? > > for example,following code is imperfect.please perfect it. > > data1 = rand(1,n) % suppose data1 is my data. > > data2 = dct(data) % data2 is discrete cosine transform of data1. > > > > % now!How draw it's figure in discrete frequency domain and leave out f > f1 ? > > ghasem
Interval in frequency is: df=1/(2*N*dt); where N is no of data and dt is the interval between data. f1 corresponds to index no: indx=round(f1/df); So, for dct Y: Y(indx:end)=0; y=idct(Y);

