Phase-locked loop methods and structures for generating modulated communication signals with nonconstant envelopes
US6693969B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 11, 2000 |
| Grant date | Feb 17, 2004 |
| Priority date | — |
| Expiry date | Jan 9, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/20
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Phase-locked loop methods and structures are provided for generating modulated communication signals with nonconstant envelopes. These methods and structures realize the improved communication performance of nonconstant-envelope modulations with the upconversion advantages of phase-locked loops. The structures include transmitters in which a phase-locked loop is augmented with first and second feedforward paths that substantially restore phase and amplitude information to a transmit signal that is generated by a voltage-controlled oscillator of the phase-locked loop. The first feedforward path is configured to realize a path transfer function of s/Kv wherein the voltage-controlled oscillator has a transfer function of Kv/s. The second feedforward path extracts an envelope-correction signal from the modulated intermediate-frequency signal and a variable-gain output amplifier amplifies the transmit signal with a gain that responds to the envelope-correction signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.