×

Active noise reduction system

  • US 4,985,925 A
  • Filed: 06/24/1988
  • Issued: 01/15/1991
  • Est. Priority Date: 06/24/1988
  • Status: Expired due to Term
First Claim
Patent Images

1. An earplug for placement in an ear canal with communication capability provided by a speaker, comprising:

  • a speaker for converting an electrical signal into an acoustical output;

    a summing microphone;

    an external active noise reduction circuit;

    a cable connecting the speaker and the summing microphone to said external active noise reduction circuit;

    an enclosure for supporting said speaker, said summing microphone, and said cable;

    a hollow earplug adapter, the enclosure being mounted inside of said hollow earplug adapter, the enclosure and said earplug adapter having openings allowing close acoustical coupling among the speaker, the summing microphone, and the ear canal; and

    said hollow earplug adapter forming an acoustical seal between the enclosure, a concha fossa and/or an ear canal wall, thereby acoustically isolating a small volume of the ear canal from ambient noise providing a quiet zone for active noise reduction.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×