TASK
Your task is to design, implement and evaluate a signal filtering system that applies a linear-phase low-pass filter to a square wave to turn it into a sinusoidal waveform. The square wave should be made with the Simulink 'Pulse Generator'. It should be set to a frequency of 1 KHz. It should be set to use the sample-based pulse type. Set the sample time to be the reciprocal of the frequency. The square wave harmonics higher than 1 kHz should be reduced by 80 dB by the filter. Use the scope and spectrum scope to assess input and output waveforms as appropriate. If you need to input two waveforms to the spectrum scope use the matrix concatenate block. The sampling frequency should be 48 kHz. Set this in the configuration parameters, the FDAtool and in the pulse generator.
This system should be tested just with Simulink's input-output facilities. As above, these input-output facilities include the pulse generator, the spectrum scope and the time scope. It is not required to use the signal processing lab. The standard Matlab copy in the normal open access computer rooms contains all the resources you need. Use the ver command to check that the signal processing toolbox is present. Remember to use the dspstartup command before entering Simulink to set up the parameters for dsp processing.
Your report must use theory from textbooks and/or electronic sources, with references.
REPORT
a. Introduction - outline the major areas of theory in relationship to low-pass filter design in Matlab (up to two pages).
b. Describe by reference to paper and electronic sources the theoretical analysis you have done to choose low-pass filter parameters that will be entered into Simulink.
c. You need to describe your Simulink design in detail, including the square wave oscillator and the low-pass filter. Describe the test methodology being used. Produce tables and graphs of results. Spectral analysis of input and output signals will be necessary. Explain important features from the tables and graphs. Send copies of the Simulink .mdl file to the module's CUOnline site.
d. Write conclusions about your exercises. Refer back to your results to prove the task requirements were met.