Quick Start

Hopefully, a person could start using the MATLAB Strobe Demo tool without any need to read these help files. Features were designed to be intuitive and familiar to those with basic computer experience.

For those who like to read the manual, this section will give you the minimum you need to get started and be comfortable with the use of the GUI.

First, if you have not already done so, follow the information given in the Installation section to install and start the MATLAB Strobe Demo tool.

  1. To begin with, set the motor's frequency, this will determine the angular frequency of the arrow. You can set the frequency in Hz by using the Motor Frequency (Hz) edit-box. Another way to set the motor's frequency is, you can use the Motor rotations/min slider/edit-box to set the motor frequency in revolutions per minute. You should be able to see change in Samples plot and the corresponding Spectrums.
  2. You can also set the strobe's flashing rate at which the disk's arrow is sampled. This can be done using the Flash Frequency (Hz) edit-box at bottom-right of the GUI, which sets the sampling frequency in Hz. The flashing rate can be alternatively specified in flashes per minute by using the Flashes/min slider/edit-box.
  3. Once the motor frequency and the strobe's flashing frequency has been set, you can use keyboard keys k and l to change the flashing rate and observe changes made to Samples and Spectrums plots. If the flashing frequency selected is less than the Nyquist rate (2*Motor Frequency), then you will see the text ALIASING! displayed in the Discrete Time Spectrum plot, indicating aliasing.
  4. You can also toggle the Fine radio button to change the step-size when advancing the sliders.
  5. Another useful feature of the Demo is its color-coded plots.
    • If the frequency of the motor lies within the range indicated by the 'yellow' strip, then the arrow is not aliased.
    • Un-aliased frequency components are marked in 'blue' and the aliased components are marked in 'red', in the spectrum plots.
    • When Aliasing occurs, such that the rotation of the arrow appears to reverse its direction, then the text ALIASING! is displayed in the Discrete Time Spectrum plot axis.

That's it!  You now understand the basics of how to use the MATLAB Strobe Demo tool; For a more in depth description of the theory behind Strobe Demonstration see the Theory section. The Controls and Menus sections provide a description of the various elements in the user interface.