3809828

Information

• Patent Grant
• 3809828

• References
• Source

• Patent Number

  3,809,828

• Date Filed

  Not available

• Date Issued

  Tuesday, May 7, 1974
  51 years ago

• CPC

  • H04R19/10 - signals being recorded or played back by vibration of a stylus in two orthogonal directions simultaneously
  • H04R19/01 - characterised by the use of electrets

• US Classifications

  • 307 - Electrical transmission or interconnection systems
  • 369 - Dynamic information storage or retrieval
  • 381 - Electrical audio signal processing systems and devices