Understanding Fourier Transform

An Introduction to Digital Signal Processing

Introduction

  • Explanation of the need to understand basic principles before diving into signal processing algorithms.
  • The beauty of mathematics and its role in digital signal processing.
  • Overview of the types of oscillations in nature.
  • Introduction to the laboratory setup.
  • Personal experience and motivation for learning math analysis.
  • Explanation of the graphs and coordinate systems used in the presentation.

Fourier Transform

  • Explanation of how Fourier transform is essential in digital signal processing.
  • Introducing the concept of complex plane and its representation of complex numbers.
  • Visual representation of the amplitude of oscillations on a graph.
  • Demonstration of the transformation process using a rotating line on the complex plane.
  • Relating the length of the line on the complex plane to the amplitude of the signal.

Frequency Analysis

  • Explanation of how frequency analysis helps understand the periodicity of a signal.
  • Finding the period of oscillation and calculating the frequency.
  • Demonstration of the movement of the center of mass on the complex plane.
  • Relating the position of the center of mass to the number of oscillation cycles.
  • Observing the behavior of the signal as the frequency of rotation matches the signal frequency.

Zero Frequency

  • Exploring the significance of zero frequency in signal rotation.
  • Demonstrating the representation of zero frequency on the complex plane.
  • Visualizing the behavior of the signal when the frequency of rotation is zero.
  • Understanding the influence of negative signal values on the rotation.
  • Observing the change in the shape of the signal when the frequency of rotation matches the signal frequency.

Multiple Frequencies

  • Exploring the decomposition of a signal with multiple frequencies.
  • Demonstration of a signal with two different frequencies.
  • Observation of the decomposition process and extraction of individual components.
  • Incorporation of an additional frequency component in the signal.
  • Confirmation of the successful decomposition of multiple frequencies.

Fourier Transform Formula

  • Introduction to the mathematical formulas for the Fourier transform.
  • Deriving the discrete Fourier transform formula.
  • Relating the rotation of the complex plane to the functions representing the horizontal and vertical coordinates.
  • Conversion of the discrete formula to the integral form.
  • Comparison to the classical definition of the Fourier transform.