Quadrature oscillator with phase error correction
US6891440B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Dec 21, 2000 |
| Grant date | May 10, 2005 |
| Priority date | — |
| Expiry date | Oct 27, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2027/0016
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A quadrature oscillator with phase error correction including a local oscillator that generates a single-ended clock signal, a single-ended to differential converter that converts the clock signal to a differential clock signal, a quadrature generator that converts the differential clock signal into I and Q carrier signals, a phase error detector that measures a phase error between the I and Q carrier signals, and a feedback amplifier that modifies the differential clock signal based on measured phase error. The feedback amplifier applies the measured phase error as a DC offset to an AC differential clock signal. A transconductor converts the differential clock voltage signal into two pairs of differential current clock signals, where the quadrature generator generates I and Q current signal outputs from the two pairs of differential current clock signals. The phase error detector generates a phase error voltage, and the feedback amplifier includes a transconductance stage that converts phase error voltage into a DC correction current and that adds the correction current to each of the two pairs of AC differential current clock signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.