Fourier Analysis - Redes de Computadores - UPV

In the right, the required information to perform the Fourier analysis is shown (The
transmitted character, transmission speed and channel bandwidth (BW). Also additional
info is presented as the time of one bit, the signal period, the fundamental frequency and
the number of passing harmonics.
In the top of the window the input signal (in blue) an the output signal (received signal)
are shown. The input and output signals are defined by byte(x) and s(x) functions,
respectively.
In the bottom, the frequency domain of the received signal is shown. Every harmonic is
represented by a vertical red line. The position of each harmonic in the X-axis
represents its frequency and its amplitude corresponds with the power of this harmonic.
We can observe that channel bandwidth is marked by a vertical blue arrow, just on the
cut frequency (fc).
Programming section: How to compute the a0, an and bn coefficients.
Firstly, you have to edit the Fourier.cpp file and take a first look. The first functions
have only defined their header, being their body empty:
double a(int n, int caracter)
{
// IMPLEMENTAR
}
double b(int n, int caracter)
{
// IMPLEMENTAR
}
double a0(int caracter)
{
// IMPLEMENTAR
}
The two first functions are the ones that calculate the an and bn coefficients. For that
purpose, use the equations (9) and (10), where the input argument, n, specifies the
harmonic order. Using the following expression bit(caracter,i) you can get the value of
bit(i). The third function is about the a0 calculation which can be done through the use
of expression (8). In order to return the results in all these functions you have to use the
return command.
Alter implementing the above functions, we will debug the program and verify its
correctness. To call compiler in Linux:
gcc Fourier.cpp –o MiFourier –lm
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