MSK digital data synchronization detector
US4028490A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 14, 1975 |
| Grant date | Jun 7, 1977 |
| Priority date | — |
| Expiry date | Nov 14, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/22
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Baudot code characters each having start and stop bits are transmitted in the form of a MSK digital data signal having a stop-start triangle corresponding to adjacent stop and start bits of two adjacent Baudot characters. The MSK signal is correlated with MSK correlation waveforms to produce first and second correlation signals. Each of the first and second correlation signals are coupled to a different one of two delay lines each having three output taps separated by one bit time. The output signals from the output taps at a given time are appropriately summed to provide inphase and quadrature triangle signals. These triangle signals are operated on by an arithmetic unit to calculate many time and phase conditions of the MSK signal at one time and to produce third, fourth and fifth correlation signals as a function of assumed bit times. These third, fourth and fifth correlation signals are operated on by a ratio calculator to produce a ratio signal proportional to the ratio of a minimum magnitude squared to a maximum magnitude squared for all carrier phase angles for each of the assumed bit times. A synchronization detected signal is produced when the ratio signal value is less th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.