| Communications Toolbox | |
Technical Conventions
This section mentions some technical conventions that this guide uses.
Polynomials as Vectors
MATLAB represents a polynomial in one variable x using a vector that lists the polynomial's coefficients, arranged according to the powers of x. Descending order means that the coefficient of the highest power of x appears first and that the polynomial's constant term appears last. Ascending order is the opposite. The table below illustrates the conventions for functions in this toolbox and for built-in MATLAB functions.
| Category of Functions |
Vector That Represents the Polynomial 1+2x+3x2 |
| Error-control coding or Galois field computations |
[1, 2, 3] (ascending order) |
| Modulation/demodulation, e.g., when using filters |
[3, 2, 1] (descending order) |
Built-in MATLAB, e.g., roots, poly, polyval |
[3, 2, 1] (descending order) |
Matrices
Matrix dimensions are described by listing the number of rows and the number of columns of the matrix in that order, as below.
u = [1 2 3;4 5 6] % A 2-by-3 matrix
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