DSP Blockset

Signals

Signals in Simulink can be real or complex valued and represented with data types such as single, double, and fixed point. Signals can be either sample based or frame based. You can typically specify the frame status (frame based or sample based) of any signal that you generate using a source block (from the DSP Sources library). Most other DSP blocks generally preserve the frame status of an input signal, but some do not.

Sample-Based Signals

A signal is sample based if it is propagated through the model sample-by-sample. If there is only one independent sequence of numbers, the signal is a single-channel signal. Sample-based multichannel signals are represented as matrices. An M-by-N sample-based matrix represents M*N independent channels, each containing a single value. Each matrix element represents one sample from a distinct channel. In order to represent multiple values from multiple channels, you must create a three dimensional matrix. The third dimension of this matrix represents the sequential values of the sample-based signal in the channels.

Frame-Based Signals

A frame of data is a collection of sequential samples from a single channel. In Simulink, a length-M frame of data is represented by an M-by-1 matrix (column vector). A single frame can be propagated through the model at one time, thus improving computational time. Frame-based multichannel signals are also represented as matrices. An M-by-N frame-based matrix represents M consecutive samples from each of N independent channels. In other words, each matrix row represents one sample (or time slice) from N distinct signal channels, and each matrix column represents M consecutive samples from a single channel.

Definitions and Nomenclature

Sampling