Apparatus for detecting the rhythm of an NRZ message
US4029905A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 17, 1975 |
| Grant date | Jun 14, 1977 |
| Priority date | — |
| Expiry date | Nov 17, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/033
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The device comes within the branch of digital transmission and refers more particularly to the problem of the recognition of a message coded in the "no return to zero" code, which is usually rhythmed by a given frequency. According to the invention, a phase-locked loop is provided for reconstituting the original rhythm from the message, and a phase shifter having an instantaneous action is additionally provided in that loop. The analysis of the reaction of the loop after that phase shift, by means of integrators, gives a statistical data information on the existence of a message. The invention applies more particularly to very noisy NRZ transmission lines.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.