1768211

Information

• Patent Grant
• 1768211

• References
• Source

• Patent Number

  1,768,211

• Date Filed

  Not available

• Date Issued

  Tuesday, June 24, 1930
  94 years ago

• CPC

  • H04R21/023 - with more than one granular chamber

• US Classifications

  • 381 - Electrical audio signal processing systems and devices