FFT analysis in Simulink - Mini Project: Build & Apply

FFT analysis in Simulink

📖 Scenario: You are working on analyzing signals in Simulink. You want to learn how to perform a Fast Fourier Transform (FFT) analysis to see the frequency components of a signal.

🎯 Goal: Build a Simulink model that generates a sine wave signal, configures FFT analysis parameters, applies the FFT block to the signal, and displays the frequency spectrum.

📋 What You'll Learn

Create a sine wave source block with specific frequency and amplitude

Add a variable to set the FFT length

Use the FFT block to analyze the sine wave signal

Display the FFT output using a Spectrum Scope block

💡 Why This Matters

🌍 Real World

FFT analysis is used in engineering and science to understand the frequency content of signals, such as audio, vibration, or communication signals.

💼 Career

Knowing how to perform FFT analysis in Simulink is useful for engineers working in signal processing, control systems, and embedded system design.

1

Create a sine wave signal source

In your Simulink model, add a Sine Wave block. Set its Amplitude parameter to 1 and Frequency parameter to 50 Hz. This will create a sine wave signal to analyze.

Simulink

% Add a Sine Wave block with Amplitude 1 and Frequency 50 Hz
% Your code here

Hint

Use the Simulink library browser to find the Sine Wave block. Double-click it to set the amplitude and frequency.

2

Set FFT length parameter

Create a variable called fftLength in the MATLAB workspace and set it to 256. This variable will be used to configure the FFT block length.

Simulink

% Add a variable called fftLength and set it to 256
% Your code here

Hint

In the MATLAB command window or script, type fftLength = 256;

3

Add FFT block and configure it

In your Simulink model, add an FFT block from the DSP System Toolbox. Set its FFT length parameter to the variable fftLength. Connect the output of the Sine Wave block to the input of the FFT block.

Simulink

% Add an FFT block and set its FFT length to fftLength
% Connect Sine Wave output to FFT input
% Your code here

Hint

Use the DSP System Toolbox to find the FFT block. Set the FFT length parameter to fftLength by typing fftLength in the parameter field.

4

Display FFT output with Spectrum Scope

Add a Spectrum Scope block from the DSP System Toolbox. Connect the output of the FFT block to the input of the Spectrum Scope block. Run the simulation and observe the frequency spectrum of the sine wave.

Simulink

% Add a Spectrum Scope block
% Connect FFT output to Spectrum Scope input
% Run the simulation
% Your code here

Hint

Find the Spectrum Scope block in DSP System Toolbox and connect it to the FFT output. Run the simulation to view the spectrum.