Digital FM modulator using direct digital synthesizer
US5272454A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Aug 14, 1992 |
| Grant date | Dec 21, 1993 |
| Priority date | — |
| Expiry date | Aug 14, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03C3/00
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A digital FM modulator includes an A/D converter, a multiplier, an adder, a direct digital synthesizer, and an addition data output circuit. The A/D converter digitally encodes an input modulation signal. The multiplier multiplies an output from the A/D converter and multiplication data input from an external circuit. The adder adds output data from the multiplier to addition data. The direct digital synthesizer changes an oscillation frequency on the basis of output data from the adder with respect to a reference frequency of a reference oscillator. The addition data output circuit changes the addition data to prevent a center frequency from changing in accordance with the multiplication data and outputs the addition data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.