3909549

Information

• Patent Grant
• 3909549

• References
• Source

• Patent Number

  3,909,549

• Date Filed

  Not available

• Date Issued

  Tuesday, September 30, 1975
  49 years ago

• CPC

  • H03H11/1295 - Parallel-T filters
  • H03H11/1217 - using a plurality of operational amplifiers
  • H04Q1/46 - comprising means for distinguishing between a signalling current of predetermined frequency and a complex current containing that frequency

• US Classifications

  • 375 - Pulse or digital communications