Image-rejection receiver
US6516186B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1999 |
| Grant date | Feb 4, 2003 |
| Priority date | — |
| Expiry date | Sep 22, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D3/007
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
In an image-rejection receiver having a first frequency conversion stage (1, 2, 9) having a pair of frequency mixers (1,2) each supplied external radio frequency signal (RF) and first local frequency signal (LOCAL1) with quadrature phase relations (9), a second frequency conversion stage (3-6, 10) having two pairs of frequency mixers (3-4, 5-6) at each output of each first stage mixer and second local frequency signal (LOCAL2) with quadrature phase relations (10), and an adder (7) and a subtractor (8) for providing sum and difference of amplitude of outputs of said second frequency conversion stage to provide inphase component (BBI) and quadrature-phase component (BBQ), no filter is used for removing an undesirable image signal which is generated in frequency conversion. A control circuit (11) is provided to keep accurate quadrature phase relations for said first local frequency signal, and said second local frequency signal, by measuring D.C. component of a product of outputs of two of mixers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.