3690144

Information

• Patent Grant
• 3690144

• References
• Source

• Patent Number

  3,690,144

• Date Filed

  Not available

• Date Issued

  Tuesday, September 12, 1972
  52 years ago

• CPC

  • G04D1/063 - provided with a pick-up means
  • G04D7/002 - Electrical measuring and testing apparatus
  • H04R1/46 - Special adaptations for use as contact microphones
  • H04R17/02 - Microphones

• US Classifications

  • 073 - Measuring and testing
  • 968 - Horology