Transmitter
First Claim
1. A transmitter comprising:
- modulated signal generating means for generating a modulated signal;
amplitude extracting means for extracting an amplitude component from the modulated signal generated by the modulated signal generating means;
amplitude amplifying means having a feedback circuit and for amplifying the amplitude component extracted by the amplitude extracting means;
voltage converting means for voltage-converting the amplitude component amplified by the amplitude amplifying means;
control means for outputting a control signal according to a signal related to a level of the amplitude component of the modulated signal generated by the modulated signal generating means;
voltage adjusting means for outputting the amplitude component voltage-converted by the voltage converting means, said amplitude component being changed by the control signal from the control means; and
a radio-frequency power amplifier where the modulated signal is inputted to a radio-frequency modulated signal input terminal, the amplitude component outputted from the voltage adjusting means is inputted to a supply voltage terminal, and a modulated wave is outputted as a result, wherein of the amplitude component returning from an output terminal of the radio-frequency power amplifier to the amplitude amplifying means through the voltage adjusting means and the feedback circuit, a high frequency component that affects a characteristic of a closed loop by the feedback circuit of the amplitude amplifying means is suppressed by the voltage adjusting means according to the control signal.
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Accused Products
Abstract
In a transmitter of the present invention, a modulated signal is separated into an amplitude component and a phase component which are inputted to a radio-frequency modulated signal input terminal and a supply voltage terminal of a radio-frequency power amplifier. A voltage adjustment circuit is provided between an output terminal of the radio-frequency power amplifier and an amplitude amplification circuit having a feedback circuit. The voltage adjustment circuit changes the amount of isolation in accordance with the voltage level of the amplitude component. By this, the amplitude component of the radio-frequency modulated wave attenuates the level inputted to the feedback circuit of the amplitude amplification circuit through the supply voltage terminal of the radio-frequency power amplifier.
27 Citations
10 Claims
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1. A transmitter comprising:
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modulated signal generating means for generating a modulated signal;
amplitude extracting means for extracting an amplitude component from the modulated signal generated by the modulated signal generating means;
amplitude amplifying means having a feedback circuit and for amplifying the amplitude component extracted by the amplitude extracting means;
voltage converting means for voltage-converting the amplitude component amplified by the amplitude amplifying means;
control means for outputting a control signal according to a signal related to a level of the amplitude component of the modulated signal generated by the modulated signal generating means;
voltage adjusting means for outputting the amplitude component voltage-converted by the voltage converting means, said amplitude component being changed by the control signal from the control means; and
a radio-frequency power amplifier where the modulated signal is inputted to a radio-frequency modulated signal input terminal, the amplitude component outputted from the voltage adjusting means is inputted to a supply voltage terminal, and a modulated wave is outputted as a result, wherein of the amplitude component returning from an output terminal of the radio-frequency power amplifier to the amplitude amplifying means through the voltage adjusting means and the feedback circuit, a high frequency component that affects a characteristic of a closed loop by the feedback circuit of the amplitude amplifying means is suppressed by the voltage adjusting means according to the control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification