Frequency Hopping Spread Spectrum (FHSS) and Hedy Lamarr

Hedy Lamarr publicity photo for the film The Heavenly Body, 1944 from Wikipedia
Hedy Lamarr publicity photo for the film The Heavenly Body, 1944 from Wikipedia

Sending coded messages is important in our modern world from wifi, cell phones, to satellites.  How to keep the information from being intercepted is key. In this unit we look at how jump frequencies to create a hacker-proof encoding process.  We also look at the how these technologies created from Hedy Lamarr and George Antheil work made our modern communications possible.

Goal

  • Convey knowledge and understanding of frequency hopping spread spectrum (FHSS) and Hedy Lamarr’s role in the development.

How actress Hedy Lamarr helped to invent frequency hopping – The Telegraph

Frequency Hopping Graphic
Image from The Telegraph video explaining Frequency Hopping and Hedy Lamarr

Frequency-hopping Spread Spectrum Terms and Concepts

  • Place them here…

Product

  • Create a blog post with embedded media from SoundCloud, YouTube, and Flickr of … Include notes, definitions, and explanations and key terms, concepts and processes.

Examples

  • Coming soon…

Steps

  • Day 1 – Create Blog Post, Add Section Headings, Listen to Podcast and Take Notes
    • Create blog post titled, Frequency-hopping Spread Spectrum
    • Copy and paste the headings below
      • Summary
      • Frequency-hopping Spread Spectrum in History
      • Frequency-hopping Spread Spectrum
      • Frequency Hopping Exercise
      • What I Learned and Problems I Solved
    • Under the Frequency-hopping Spread Spectrumin History heading:
  • Day 2 – Phasing Sound Terms and Concepts
  • Day 3-4 – Create Two Sound Tracks: One in Phase and One Out of Phase
    • Review terms from yesterday
    • Record an audio track in Audacity
    • Duplicate the region of audio so that it plays twice in the track
    • Duplicate the track
    • Invert the second region of the duplicated track
    • Play the tracks
    • Listen for the difference in the regions
    • Export as a mp3, upload to SoundCloud, and embed under the Sound Waves – In and Out of Phase heading
    • Explain what you learned under the What I Learned and Problems I Solved heading
  • Day 5-6 – Create Two Tracks: One with Voice and One as an Encryption Key ‘Noise’ Track
    • Track 1: Record a voice track in Audacity
    • Track 1: Duplicate the voice region of audio so that there are three instances of it on this track
    • Track 2: Record a second track of noise, generated by Audacity or another source,  underneath the second region of the voice track
    • Track 2: Copy and paste the noise region under the third region of voice
    • Track 3: Copy and paste the noise region from track 2 under the third voice region
    • Track 3: Invert the noise region
    • Play the tracks
      • Listen for the difference in the regions
      • You should hear the voice region, then the noise encrypted voice region, then finally the decoded noise and voice region
    • Export as a mp3, upload to SoundCloud, and embed under the Encoding and Decoding with Sound Waves heading
    • Explain what you learned under the What I Learned and Problems I Solved heading
  • Day 7 – Finish Work and Publish Blog Post
    • Under the What I Learned and Problems I Solved heading
      • Explain what you learned and at least one problem you overcame
      • Include a link to a tutorial you used and
      • Describe how you used it
    • Under the Summary heading
      • Write a brief description overview of the whole project
  • Day 8
    • Present sound files

Tools

  • Audacity
  • Soundcloud
  • YouTube
  • Flickr

Resources

Feedback Form

  • Frequency-hopping and Hedy Lamarr Project Feedback Form (PDF) – COMING SOON!

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