Method and apparatus for code conversion of binary of multilevel signals
US4528550A · kind A · utility
51Cited by
7References
2Claims
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Key dates
| Filing date | Oct 31, 1983 |
| Grant date | Jul 9, 1985 |
| Priority date | — |
| Expiry date | Oct 31, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/4919
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Apparatus for converting binary to quaternary-level signals in which the symbols of selected words are inverted in order to eliminate the d-c component of the signal. In order to reduce the power spectral density at frequencies close to d-c and increase the power spectral density at frequencies close to the Nyquist rate, one word of each frame is selectively inverted relative to another in order to maximize the summation of all the numerical values of the differences between adjacent symbol levels. Thereafter both words of the frame are selectively inverted in order to minimize the running digital sum of the signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.