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US 6,643,497 B1Granted
Portable telephone compensable for change of antenna impedance
AssigneeNEC Corporation
InventorNaoyuki Kouyama
Life of this patent
Estimating the term…
Abstract
A portable telephone is provided, which eliminates or effectively suppresses the change of the antenna impedance due to approach or contact of a human body with the telephone. The telephone operates without using sensing detection devices for recognizing the actual approach or contact of a human body with the phone. The device insures the desired antenna characteristics with a simple and low-cost configuration. Different impedance values of an impedance matching subsystem are switched so as to be interlocked with a start and stop of a talking state of the portable telephone.
Claims20
A portable telephone comprising:
- an antenna;
- a radio section for processing a radio-frequency reception signal received by said antenna and for processing a radio-frequency transmission signal to be transmitted and sending said radio-frequency transmission signal thus processed to said antenna;
- a control section for controlling said radio section;
- and
- an impedance matching subsystem for matching an impedance of said antenna with an impedance of said radio section;
- said impedance matching subsystem comprising different impedance values,
- wherein the different impedance values of said impedance matching subsystem are switched with a start and stop of a talking state of said telephone, and
- wherein the start and stop of said talking state of said telephone is determined by a start and stop of audio information in said radio-frequency reception signal.
5 more elements
A portable telephone comprising:
- an antenna;
- a radio section for processing a radio-frequency reception signal received by said antenna and for processing a radio-frequency transmission signal to be transmitted and sending said radio-frequency transmission signal thus processed to said antenna;
- a control section for controlling said radio section;
- an impedance matching subsystem for matching an impedance of said antenna with an impedance of said radio section;said impedance matching subsystem being designed to have different impedance values;
- the different impedance values of said impedance matching subsystem being switched so as to be interlocked with start and stop of a talking state of said telephone;
- and
- an at least one additional antenna, wherein the different impedance values of said impedance matching subsystem are changed between said antenna and the at least one additional antenna to compensate for the influence of a human body.
4 more elements
A portable telephone comprising:
- an antenna;
- a radio section for processing a radio-frequency reception signal received by said antenna and for processing a radio-frequency transmission signal to be transmitted, and sending said radio-frequency transmission signal thus processed to said antenna;
- a control section for controlling said radio section, wherein said control section comprises a reception signal processing circuit;
- said reception signal processing circuit including an audio-frequency signal amplifier circuit for amplifying an audio-frequency signal generated by demodulating said radio-frequency reception signal;
- and
- an impedance matching subsystem for matching an impedance of said antenna with an impedance of said radio section;
- said impedance matching subsystem being designed to have different impedance values, the different impedance values of said impedance matching subsystem being switched so as to be interlocked with start and stop of a talking state of said telephone;
- wherein the start and stop of said talking state of said telephone is detected by detecting start and stop of operation of said audio-frequency signal amplifier circuit, thereby switching the different impedance values of said impedance matching subsystem.
5 more elements
A portable telephone, comprising:
- an antenna;
- a radio section for processing a radio-frequency reception signal received by said antenna and for processing a radio-frequency transmission signal to be transmitted and sending said radio-frequency transmission signal thus processed to said antenna;
- a control section for controlling said radio section;
- and
- an impedance matching subsystem for matching an impedance of said antenna with an impedance of said radio section;
- said impedance matching subsystem being designed to have different impedance values;
- the different impedance values of said impedance matching subsystem being switched so as to be interlocked with start and stop of a talking state of said telephone,
- wherein a first one of the different impedance values of said impedance matching subsystem is set at a value that optimizes impedance matching between said antenna and said radio section without taking an influence of a human body into consideration;
- the first one of the different impedance values being selected when said telephone is not in the talking state;
- and
- wherein a second one of the different impedance values of said impedance matching subsystem is set at a value that optimizes impedance matching between said antenna and said radio section with taking an influence of a human body into consideration;
- the second one of the different impedance values being selected when said telephone is in the talking state.
9 more elements
A portable telephone, comprising:
- an antenna;
- a radio section for processing a radio-frequency reception signal received by said antenna and for processing a radio-frequency transmission signal to be transmitted and sending said radio-frequency transmission signal thus processed to said antenna;
- a control section for controlling said radio section;
- and
- an impedance matching subsystem for matching an impedance of said antenna with an impedance of said radio section;
- said impedance matching subsystem being designed to have different impedance values;
- the different impedance values of said impedance matching subsystem being switched so as to be interlocked with start and stop of a talking state of said telephone,
- wherein a return loss of said antenna seen from said radio section is minimized at a first frequency when said telephone is in the talking state and at a second frequency when said telephone is not in the talking state;
- the first frequency being higher than the second frequency;
- and
- wherein the first frequency is changed to a frequency equal or near the second frequency due to the influence of a human body.
8 more elements
A portable telephone comprising:
- a radio section comprising a reception signal processing circuit, wherein said reception signal processing circuit includes an audio-frequency signal amplifier circuit for amplifying an audio-frequency signal generated by demodulating a radio-frequency reception signal;
- and
- an impedance matching subsystem for matching an impedance of said antenna with an impedance of said radio section, said impedance matching subsystem being designed to have different impedance values,
- wherein the different impedance values of said impedance matching subsystem are changed according to the start and stop of a talking state of said telephone, and
- wherein the start and stop of said talking state of said telephone is detected by detecting start and stop of operation of said audio-frequency signal amplifier circuit, thereby switching the different impedance values of said impedance matching subsystem.
2 more elements
Dependencies are inferred from the claim text.