Sampling sinusoidal signals in matlab in signal processing, sampling is the reduction of a continuoustime signal to a discretetime signal. In simulations, we may require to generate a continuous time signal and convert it to discrete domain by appropriate sampling. Matlab program for sampling theorem and aliasing effect 09. Mireille boutin fall 2016 1 introduction the purpose of this lab is to illustrate the properties of continuous and discrete time signals using digital computers and the matlab software environment. Matlab or any other simulation softwares process everything in digital i. A continuous time signal can be processed by processing its samples through a discrete time system. Simulink models can process both discretetime and continuoustime signals. Sampling and recovery using matlab signal processing. Functions this script demonstrates nyquists sampling theorem, by sampling a continuoustime sinusoidal signal of a frequency f 50 hz to 3. A discretetime signal is a sequence of values that correspond to particular instants in time. A continuous time signal can be represented by its samples and can be. The internal state includes but is not limited to continuous and discrete states that are logged.
This is because, the signals are represented as discrete samples in computer memory. Interactive demo of nyquists sampling theorem file. You can create a sampling vector tsample every 2ms which corresponds to f500hz and then get the value of your signal at this points. Converting it to a continuoustime signal would require that you pass it through an appropriatelydesigned. Do not confuse the simulink usage of the term sample time. Models built with dsp system toolbox software are often intended to process discretetime signals only. Discrete and continuoustime signals purdue engineering. The signal will remain a sampled signal in your computer because that is the only way signals can be represented in computers. Discretetime or continuoustime sample and hold input signal.
The simulink signal generator and constant blocks are examples of continuoustime source blocks. Sampling and reconstructing signals in matlab stack overflow. The sample period for continuoustime source blocks is set internally to zero. Has sliders to change the amplitude, theta, and frequency.
Original signal sampling impulse train sampled signal. Source blocks are those blocks that generate or import signals in a model. Sampling and reconstruction of signal in matlab signal processing. Your signal was likely sampled using a zeroorderhold. Lets assume the length is 1 second and the units are in us. Therefore, we cannot generate a real continuoustime signal on it, rather we can generate a continuouslike signal by using a very very high sampling rate. This set of lectures discusses sampling of continuous time signals. This introduction video outlines the different topics that will be covered i.
Basic continuoustime and discretetime signals gui mathworks. Sampling and manipulating a signal in matlab and downsampling. This information can be found other places as well but i will step through it here using matlab. Reconstruct a sampled signal with zoh matlab answers. The time instants at which the signal is defined are the signals sample times.
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