I want to ask you the following question. I found the following example on the MatLab page, which I can't understand what the function does genqammod
and how the vector is defined x = []
. I don't understand what values I have to use. I leave you the following link of the example
Example: https://la.mathworks.com/help/comm/ref/genqammod.html.
The function
genqammod
or its original nomenclature General quadrature amplitude modulation (QAM) is a function that allows quadrature amplitude modulation .Quadrature amplitude modulation is a technique that transports two independent signals, by modulating or shifting, both in amplitude and in phase, two carrier signals with the same frequency but which are 90° out of phase with each other. The QAM modulated signal is composed of the linear sum of the two previously modulated signals.
Applications
As a current student I have used this function on a few occasions for Physics-related topics, especially for Circuit Theory . In a very general and simplified way , if we go into Physics, this type of modulation serves to favor the use of the available bandwidth
Syntax
Regarding the way to define a vector, it is necessary to make a clear differentiation. A vector is not the same as a matrix, therefore, the way to define them are not the same.
To define a vector, we make use of the function
colon,:
Syntax
where creates a unit spacing
x = j:k
vector with elements of the formx
j
[j,j+1,j+2,...,j+n]
In MatLab to define an array is done as follows (Similar to creating an array)
Therefore, the matrix
a
will have dimension1x4
→a = 1x4
and will be a row matrixIf we want to define a matrix with several rows, the way to define said matrix is:
where the matrix will have dimension
a = 3×3
Finally, if we want to define a row matrix or a column matrix whose components will all be 0, we can define the matrix using the function
zeros
as follows:where the values
(5,1)
indicate the dimension of the array . In this case, it is a row matrix with 5 rows and 1 column .Example