Tuning circuit with amplitude attenuation function and integrated circuit for radio communication apparatus
US7330708B2 · kind B2 · utility
5Cited by
6References
9Claims
0Family size
Assignees
Inventors
Key dates
| Filing date | Nov 30, 2004 |
| Grant date | Feb 12, 2008 |
| Priority date | — |
| Expiry date | Mar 7, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J5/246
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
There is disclosed a tuning circuit having a coil and a capacitor comprises a resistance-adjustment circuit connected in parallel with the coil and the capacitor. The resistance-adjustment circuit changes a resistance of the tuning circuit when resonant. The resistance-adjustment circuit comprises a series circuit of a resistor and a switching element having an ON-resistance smaller than the resistance of the resistor, and turning on/off the switching element causes the resistance of the tuning circuit when resonant to change.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.