Common mode signal attenuation for a differential duplexer
US7848713B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 2007 |
| Grant date | Dec 7, 2010 |
| Priority date | — |
| Expiry date | Apr 16, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/18
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Techniques for attenuating undesired signal components from a differential duplexer are described. The duplexer provides a differential received signal at RX+ and RX− ports. This differential received signal includes an undesired common mode signal, which may come from a transmit signal. The common mode signal is attenuated with a common mode trap in an impedance matching network coupled to the RX+ and RX− ports. The matching network includes a first passive circuit coupled between the RX+ port and a first node, a second passive circuit coupled between the RX− port and a second node, and the common mode trap coupled between the first and second nodes. In one design, the common mode trap includes a first inductor coupled between the first node and a common node, a second inductor coupled between the second node and the common node, and a capacitor coupled between the common node and circuit ground.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.