Method of and system for power line carrier communications
US4968970A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 26, 1989 |
| Grant date | Nov 6, 1990 |
| Priority date | — |
| Expiry date | Apr 26, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY04S40/121
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The transmitter in a power line communications system applies to the power line encoded logical-one and logical-zero bit signals consisting of signals formed respectively of predetermined different sequences of frequencies. The receiver, coupled to the power line, includes a first homodyne, non-coherent, quadratic demodulator for demodulating the logical-one bits and a second for demodulating the logical-zero bits. The first demodulator produces, locally, and in first and second channels, respectively, a first reference signal that is a replica of the logical-one bit sequence of frequencies and a second reference signal that is the replica in quadrature. The second demodulator produces, locally, and in third and fourth channels, respectively, cooresponding third and fourth reference signals for the logical-zero bit sequence. Each of the four reference signals is applied to a corresponding analog multiplier for multiplication by the input signal in each channel. The output of each multiplier is applied to a low pass filter that passes only the dc component of the product signal which in turn is squared. The resultant signals in the first and second channels are summed to provide a f…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.