Creating a signal with desired frequency band

Hi all,

I want to create a time domain signal with desired frequency spectrum. How can I do it simple way? When I create frequency domain signal and take ifft, it has complex values which I dont want to have. Is there any other way to create it?

Here is frequency reprensation;

    x=[zeros(1,4) 16*ones(1,10) 2*ones(1,8) 20*ones(1,15) 0*ones(1,36) 24*ones(1,4) 0*ones(1,51)];

Answer 1

[Image Analyst]

Here is a table of the properties.

Time Domain        Frequency Domain
real            hermitian (real=even, imag=odd)
imaginary        anti-hermitian (real=odd, imag=even)
even            even
odd             odd
real and even      real and even (i.e. cosine transform)
real and odd       imaginary and odd (i.e. sine transform)
imaginary and even    imaginary and even
imaginary and odd    real and odd

As you can see, your signal is neither real and even, nor imaginary and odd. You have a real, unsymmetrical signal so you will have a hermitian (complex) result.