Transmitting signals over alternating current power networks
Patent 4307380 Issued on December 22, 1981. Estimated Expiration Date: 
December 22, 1998. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
December 22, 1998. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3445814 Signal time compression or expansion system Transversal frequency filter Pulse-code modulation communication system Patent #: 4005274 InventorApplicationNo. 05/863467 filed on 12/22/1977US Classes:340/538.11, Modulation technique178/66.1, Alternating or pulsating current340/310.12, Modulation technique340/310.13, Noise reduction (e.g., filtering)340/538.12, Noise reduction (e.g., filtering)375/272, Frequency shift keying704/500AUDIO SIGNAL BANDWIDTH COMPRESSION OR EXPANSIONExaminersPrimary: Groody, James J.Attorney, Agent or FirmInternational ClassesH04B 3/54 (20060101)H02J 13/00 (20060101) Foreign Application Priority Data1977-05-17 CHAbstractThis invention relates to communication systems of the type particularly useful in power line communications. Signals to be transmitted, which can be in the form of short, fixed frequency signals, are expanded in time and/or bandwidth to provide a longer signal with a variable frequency. At the receiver, power line noise, which is typically either short wideband noise or long narrowband noise, is removed and the remaining expanded signal is detected. The expanded signal can then be compressed in time and/or bandwidth to reproduce the original signal. | |
