UTPA STEM/CBI Courses/Communication Theory/Noise

Course Title: Communication Theory

Lecture Topic: Noise

Instructor: Jae Sok Son

Institution: University of Texas-Pan American

Backwards Design

Course Objectives

• Primary Objectives- By the next class period students will be able to:
  • Learn effects of noise in communication
  • Learn various types of noise
  • Learn how to suppress the noise

• Sub Objectives- The objectives will require that students be able to:
  • Identify the noise from signal
  • Generate various types of noise using a computer

• Difficulties- Students may have difficulty:
  • Distinguishing between noise and fricative sound
  • Determining probability formula(s) for noise generation

• Real-World Contexts- There are many ways that students can use this material in the real-world, such as:
  • Implementing noise suppression for audio records
  • Creating cell phone noise cancellation for improved call quality

Model of Knowledge

• Concept Map
  • Identify common noisy situations in communication applications
  • Relate the time domain noise to the frequency domain noise
  • Relate the time domain signal to the frequency domain signal

• Content Priorities
  • Enduring Understanding
    • Understand the filter design
    • Understand the sampling principle
    • Understand the characteristics of noise and signal in a frequency domain
  • Important to Do and Know
    • Difference between the digital filter and analog filter
    • Knowledge of filter design coefficients
  • Worth Being Familiar with
    • Audio systems
    • Amplifiers
    • Speech processing

Assessment of Learning

• Formative Assessment
  • In Class (groups)
    • Record several voices from students and show the recorded sounds with PowerPoint.
    • Discuss which part of the recording is noise and which part is signal.
    • Discuss what the differences between fricatives and noises are.
  • Homework (individual)
    • Record an individual voice and suppress the noise using computer
    • Find the best filter coefficients to suppress the noise
• Summative Assessment
  • Exam on lecture and homework problems
  • Quiz on theoretical filter coefficients

Legacy Cycle

OBJECTIVE

By the next class period, students will be able to:

• Generate various type of noises

The objectives will require that students be able to:

• Understand the probability characteristics of noise

THE CHALLENGE

An electrical engineer must design a cell phone that suppresses the background noise.

GENERATE IDEAS

What kinds of background noises are present?

MULTIPLE PERSPECTIVES

Lecture on the probability mathematical model of noise and sound

RESEARCH & REVISE

Examine the differences between the noise and signal characteristics in a frequency domain. If identifying the signal is easier than identifying the noise, suggest that students pass the signals rather than suppress the noise.

TEST YOUR METTLE

Programming assignment for noise generation from the mathematical model and it add to the signal

GO PUBLIC

Quiz and Exam about noise characteristics and filter design.

Pre-Lesson Quiz

1. What probability distribution function (PDF) can model the fricative sound?
2. Most of the time, Gaussian PDF is used to model the natural sound. Explain why the Gaussian PDF is the most popular method for the simulation purpose.
3. What kind of filter is most likely used to filter out the noise in verbal communication?

Test Your Mettle Quiz

1. Gaussian, Alpha, Gamma or Weibull PDFs are used mostly to model voiced and voiceless fricatives.
2. Gaussian distribution is used due to its mathematical simplicity and ease of implementation in hardware.
3. Low pass filter will pass the voiced signal and filter out the noise.