Time-varying Viterbi detector for control of error event length
US5280489A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 15, 1992 |
| Grant date | Jan 18, 1994 |
| Priority date | — |
| Expiry date | Apr 15, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M13/31
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for detecting spectral null sequences of a spectrally-constrained code on a noisy communications channel. From a Viterbi detector with a trellis structure comprising a plurality of states and edges, predetermined ones of the states and edges in the trellis structure are deleted at preselected times modulo N, such as times .phi. modulo N and/or at intermediate times m modulo N, where m=.phi., thereby to create a time-varying trellis structure for limiting the maximum length of dominant error events. The deleted edges are generally those edges which would have entered or emanated from the deleted states if they were not deleted. The trellis structure may be a so-called systolic structure, in which case the spectral null sequences are preferably DC-free or Nyquist free.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.