Tuner and portable device using the same
First Claim
1. A tuner comprising:
- an input terminal operable to receive a high-frequency signal, the high-frequency signal including a first high-frequency signal and a second high-frequency signal, the second high-frequency signal having a level larger than a level of the first signal;
a first filter having an input port coupled to the input terminal, the first filter allowing a signal having the first frequency to pass therethrough and attenuating a signal having the second frequency;
a high-frequency amplifier coupled to an output port of the first filter;
a second filter having an input port coupled to an output of the high-frequency amplifier, the second filter allowing a signal having the first frequency to pass therethrough and attenuating the signal having the second frequency;
a local oscillator;
a mixer for mixing the output of the high-frequency amplifier with an output of the local oscillator;
an intermediate-frequency filter having an input port coupled to an output of the mixer; and
an output terminal for receiving an output of the intermediate-frequency filter.
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Accused Products
Abstract
A tuner includes an input terminal operable to receive a high-frequency signal including a first high-frequency signal and a second high-frequency signal. The second high-frequency signal has a level larger than that of the first signal. The tuner further includes a first filter having an input port coupled to the input terminal for allowing a signal having the first frequency to pass therethrough and for attenuating a signal having the second frequency, a high-frequency amplifier coupled to an output port of the first filter, a second filter having an input port coupled to an output of the high-frequency amplifier for allowing a signal having the first frequency to pass therethrough and for attenuating the signal having the second frequency, a local oscillator, and a mixer for mixing the output of the high-frequency amplifier with an output of the local oscillator. This tuner has a high receiving sensitivity even when the tuner receives a high-power interference signal near a receiving range thereof and in a weak electric field.
13 Citations
15 Claims
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1. A tuner comprising:
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an input terminal operable to receive a high-frequency signal, the high-frequency signal including a first high-frequency signal and a second high-frequency signal, the second high-frequency signal having a level larger than a level of the first signal; a first filter having an input port coupled to the input terminal, the first filter allowing a signal having the first frequency to pass therethrough and attenuating a signal having the second frequency; a high-frequency amplifier coupled to an output port of the first filter; a second filter having an input port coupled to an output of the high-frequency amplifier, the second filter allowing a signal having the first frequency to pass therethrough and attenuating the signal having the second frequency; a local oscillator; a mixer for mixing the output of the high-frequency amplifier with an output of the local oscillator; an intermediate-frequency filter having an input port coupled to an output of the mixer; and an output terminal for receiving an output of the intermediate-frequency filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A portable device comprising:
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an antenna operable to receive a high-frequency signal, the high-frequency signal including a first high-frequency signal and a second high-frequency signal, the second high-frequency signal having a level larger than a level of the first signal, a tuner including an input terminal coupled to the antenna, a first filter having an input port coupled to the input terminal, the first filter allowing a signal having the first frequency to pass therethrough and attenuating a signal having the second frequency, a high-frequency amplifier coupled to an output port of the first filter, a second filter having an input port coupled to an output of the high-frequency amplifier, the second filter allowing a signal having the first frequency to pass therethrough and attenuating the signal having the second frequency, a local oscillator, a mixer for mixing the output of the high-frequency amplifier with an output of the local oscillator, an intermediate-frequency filter having an input port coupled to an output of the mixer, and an output terminal for receiving an output of the intermediate-frequency filter; and a transmitter section for transmitting the second high-frequency signal. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification