Impedance matching circuit in transmitter circuit and control method thereof
US5862458A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 17, 1996 |
| Grant date | Jan 19, 1999 |
| Priority date | — |
| Expiry date | Apr 17, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/18
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In an impedance matching circuit used in a transmitter circuit, an occurrence of a reflection wave in an antenna is suppressed. The impedance matching circuit in a transmitter circuit includes a modulating circuit for modulating an input signal to output a modulation signal, a power amplifying circuit for power-amplifying the modulation signal, an antenna for outputting the signal power-amplified by the power amplifying circuit, a demodulating circuit for demodulating the signal power-amplified by the power amplifying circuit to output a demodulation signal, a band-outside-component detecting circuit for detecting a band-outside-component of the demodulation signal, a control circuit for outputting a control signal based upon the signal derived from the band-outside-component detecting circuit, and an impedance matching circuit for matching an input impedance of the antenna with an impedance of the power amplifying circuit by changing an impedance of the impedance matching circuit based upon the control signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.