Module 3-1: Seeing Voices and Digitization

  • Due Sep 24, 2024 by 12:30pm
  • Points 0

Module 3-1

     See Your Voice

    Voice signals start out as a pressure wave (which we can hear with our ears). Then they are converted to a voltage using a piezoelectric microphone. We can look at that voltage on an oscilloscope, which we will do today (cool!). 

    Humans can hear from about 30-30,000 Hz, but the sound waves for speech (and therefore the voltage measured by a microphone) have frequencies primarily between 300 Hertz (Hz) and 3000 Hz (or 3 kHz - 3 kilohertz). 

    But modern cell phones do something else to the voice voltage signal before modulating it with the carrier wave. They convert it to a digital signal and then modulate it with the carrier wave, which is even easier for the receiver in your friend's phone to pick up. We'll talk about this sampling and digitization process, and what a digital signal is.

    Learning Objectives

    • What is a sound wave, and how is it converted to a voltage?
    • How is a voltage signal digitized

    Pre-Class Assignment

    • Download an app on your phone that will let you see your voice. PhyPhox is a good one for iphone.Windows computers can use the sound recorder app.  Many other programs exist.  

    NOTE: We will provide a number of online resources, some of which may be corporate sites that are advertising services or products. Using these sites as our references should IN NO WAY imply that we are promoting these companies. In some cases, we will even provide conflicting or debatable sites for the purpose of generating thought and discussion.

    In Class Activities

    Extra Resources

    Homework

     

    1727202600 09/24/2024 12:30pm