Radio frequency tuner
US7558543B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 2006 |
| Grant date | Jul 7, 2009 |
| Priority date | — |
| Expiry date | Aug 25, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D3/009
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A radio frequency tuner includes a first quadrature frequency changer, I and Q filters which are electronically adjustable, and a second quadrature frequency changer. During alignment of the filters, an alignment controller connects a test tone generator to the input of the frequency converter and the generator supplies a sequence of test tones of different accurately known frequencies. The amplitude of the resulting signals at the output of one of the filters is measured by a level detector. The controller compares the measured levels with a desired frequency response and adjusts the filter accordingly. The controller then causes the generator to supply a sequence of two test tones of different frequencies and a differential phase detector measures the phase difference between the output signals of the mixers of the second frequency changer. The controller adjusts the response of the other filter and the test procedure is repeated until phase imbalances between the filters are substantially reduced or eliminated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.