DSP Blockset

Signal Dimension Nomenclature

The DSP Blockset fully supports Simulink's matrix format, which is described in "Working with Signals" in the Simulink documentation. The nomenclature used for vectors and matrices in the DSP Blockset is described below.

Matrices.   A Simulink matrix is the same as a MATLAB matrix, a two-dimensional (2-D) array of values, organized as rows and columns. As in MATLAB, a matrix can be indexed by one or two values. The size of a matrix is described by the number of rows M and the number of columns N. In the DSP Blockset, matrix size is usually denoted by the compact expression M-by-N or MxN, and occasionally by the MATLAB notation [M N].

For instance, a 2-by-3 matrix, like matrix u below, has two rows and three columns.

This matrix can be represented in MATLAB notation as

u = [1 2 3;4 5 6]        % A 2-by-3 matrix

In the online help, matrix elements are indexed using either subscript notation or MATLAB notation. For example, u₂₃ and u(2,3) both refer to the element in the third column of the second row. The number of channels in a frame-based matrix is the number of columns, N. More information about matrices can be found in Multichannel Signals.

Vectors.   Strictly speaking, a Simulink vector is a one-dimensional (1-D) array of values, an ordered list that has no row or column orientation. For convenience, the DSP Blockset help uses the plain term vector to refer to any of the following three entities:

• One-dimensional array, also called a 1-D vector
• 1-by-N matrix, also called a row vector
• M-by-1 matrix, also called a column vector

The size or length of a vector, M for a column vector or N for a row vector, is the number of elements that it contains. There is no MATLAB equivalent for a 1-D Simulink vector (i.e., all MATLAB vectors have either a row or column orientation), and most blocks in the DSP Blockset treat a 1-D vector as a column vector.

Arrays.   The number of pages, P, of a three-dimensional array in the MATLAB workspace refers to the size of its third dimension

A(:,:,1) = [1 2 3;4 5 6]     % The first page of a 3-page array
A(:,:,2) = [7 8 9;0 1 2]     % The second page
A(:,:,3) = [3 4 5;6 7 8]     % The last page

Array size is frequently denoted by the compact expression M-by-N-by-P or MxNxP.

Technical Conventions

Frame-Based Signal Nomenclature