Description

Matlab provides a user-friendly programming environment with great flexibility, very well-suited to modeling, analyzing physiological data and developing biomedical signal processing algorithms. In this lab we will become familiar with handling and plotting discrete-time signals in the Matlab environment – both theoretical signals we generate with equations, and real data.

Part I: mathematical function plotting Say you want to generate a sinusoid of a certain frequency, and plot it. Matlab, not being a live thinking entity, has no clue what you want to do so you need to specify EVERYTHING to it. Let’s say you want to plot a 5-Hz sinusoid over a 2-second time frame beginning at 0. We want it to have an amplitude of 2 and have a cosine phase (begins at its peak/maximum at time 0). We are trying to construct a signal that is a function of time, so we should therefore define ‘time.’ And it’s a discrete-time signal so we need a value of the signal only at discrete – usually evenly-spaced – times. Let’s choose a ‘sampling rate’ of 200 Hz, in other words, choose to evaluate the function in discrete 5-ms steps: