Tài liệu The Complex Fourier Transform

Although complex numbers are fundamentally disconnected from our reality, they can be used to
solve science and engineering problems in two ways. First, the parameters from a real world
problem can be substituted into a complex form, as presented in the last chapter. The second
method is much more elegant and powerful, a way of making the complex numbers
mathematically equivalent to the physical problem. This approach leads to the complex Fourier
transform, a more sophisticated version of the real Fourier transform discussed in Chapter 8.
The complex Fourier transform is important in itself, but also as a stepping stone to more
powerful complex techniques, such as the Laplace and z-transforms. These complex transforms
are the foundation of theoretical DSP.