Digital frequency shift key modulator
US3991389A · kind A · utility
17Cited by
6References
2Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 18, 1974 |
| Grant date | Nov 9, 1976 |
| Priority date | — |
| Expiry date | Sep 18, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03C3/00
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A frequency shift key modulator producing sine wave output signals of different frequencies for mark (1) and space (0) signal levels on an input "send data" lead including a counter which divides the frequency of an input oscillator by different denominators for the mark and space signals and the output of which is synthesized to produce a stepped output approximating a sine wave and a final filter for smoothing the steps out of the output. In cases in which the mark and space output frequencies are approximately in the ratio of 1 to 2, a frequency divider is used for the mark output frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.