Method and apparatus for transmitting binary data signals by frequency shift keying
US4724534A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 1986 |
| Grant date | Feb 9, 1988 |
| Priority date | — |
| Expiry date | Jul 7, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/122
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A modulator for modulating binary data signals by frequency shift keying (FSK), in which a binary data level 1 is represented by a first frequency (f.sub.1) and the binary data level 0 is represented by a second frequency (f.sub.2) is provided. The modulator addresses a first addressing input of a programmable memory with the binary data signals, in which half the periods of the two frequencies (f.sub.1, f.sub.2) are marked in two memory regions (I, II) of the programmable memory addressed by the first addressing input. The modulator further controls other address inputs with a driven counter; and generates a pulse resetting the counter and controlling a 2:1 frequency divider having an output delivering one of the frequencies (f.sub.1, f.sub.2), when addressing a storage cell, in which one of the halfperiods is marked.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.