Center frequency control of an integrated phase rotator band-pass filter using VCO coarse trim bits
US7421252B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 2005 |
| Grant date | Sep 2, 2008 |
| Priority date | — |
| Expiry date | Sep 5, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2001/0433
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A phase rotator for a Cartesian feedback power amplifier in a transmitter final stage contains an integrated voltage controlled tunable resonant circuit accomplishing band-pass filtering at a center frequency selected by local oscillator (LO) coarse trim control signals. The voltage controlled tunable resonant circuit attenuates input signal harmonic levels at large fractional bandwidths for the downconverter in the feedback LO path without setting a large number of poles in the band-pass filter. The binary-weighted course trim value for controlling the gain of the LO sets a bank of voltage-variable capacitors (VVC) in the voltage controlled tunable resonant circuit to control the center frequency in each of two 2-pole band-pass filters, creating a composite 4-pole band-pass filter at the input of a poly-phase quadrature generation circuit in the feedback LO path.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.