Variable rate modulator
US6870429B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 25, 2003 |
| Grant date | Mar 22, 2005 |
| Priority date | — |
| Expiry date | Jul 6, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/362
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Clock signals and digital data signals at a variable frequency are introduced to the input of a FIFO and are passed from the FIFO at a second (or intermediate) frequency controlled by a numerically controlled oscillator. To regulate the frequency of the signals from the numerically controlled oscillator, the phases of the clock signals at the variable frequency are compared in a phase detector with the phases of the signals from the numerically controlled oscillator to generate an error signal. The error signals and the signals at a fixed sampling frequency higher than the intermediate frequency regulate the frequency of the signals from the numerically controlled oscillator and thus the frequency of the digital data signals from the FIFO. The digital data signals from the FIFO are converted to a pair of signals at the second frequency. The pair of signals at the second frequency have individual ones of a plurality of analog levels dependent upon a code indicated by successive pairs of the digital data signals. The signals at the second (or intermediate) frequency modulate a pair of trigonometrically related signals at the fixed sampling frequency. The modulated signals at the fixe…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.