User`s guide

4 DSP Operations
4-10
Transforms
The Transforms library provides blocks for a number of transforms that are of
particular importance in DSP applications:
•Analytic Signal
•Complex Cepstrum
•DCT
•FFT
•IDCT
•IFFT
•Real Cepstrum
First and foremost among these are of course the FFT and IFFT blocks, which
respectively implement the fast Fourier transform and its inverse. These
blocks are discussed further in the next section.
Using the FFT and IFFT Blocks
This section provides the following two example models that use the FFT and
IFFT blocks:
•“Example: Using the FFT Block”
•“Example: Using the IFFT Block”
The first example loosely follows the example in the “Discrete Fourier
Transform” section of the Signal Processing Toolbox documentation, where you
can also find additional background information on these transform
operations.
Example: Using the FFT Block
In the model below, the Sine Wave block generates two frame-based sinusoids,
one at 15 Hz and the other at 40 Hz. The sinusoids are summed point-by-point
to generate the compound sinusoid
which is then transformed to the frequency domain using an FFT block.
u 30πt() 80πt()sin+sin=