Abstract: A power amplifier comprises an amplifier amplifying a high-frequency signal modulated by an input signal. An inverted envelope generates circuit generating an inverted envelope signal by using the input signal or the high-frequency signal The inverted envelope signal having an inverted envelope. A variable gain amplifier adjusts the amplitude of the inverted envelope signal, and a variable delay circuit adjusts a phase of the inverted envelope signal. A control circuit outputs a control signal to the variable gain amplifier and the variable delay circuit based on information about distortion or a signal level of the amplified high-frequency signal. The inverted envelope signal having been adjusted in amplitude or phase is injected to the high-frequency signal or the amplified high-frequency signal. The control circuit controls the variable gain amplifier or the variable delay circuit so that distortion or a signal level of the amplified high-frequency signal is minimum.

Abstract: A predistortion linearizer has signal dividing circuit dividing an input signal into two signals; signal adjusting circuit using one of the divided signals to execute predetermined adjustment and outputting a signal based on the adjustment; distortion signal generating circuit generating a distortion signal using the signal output from the signal adjusting circuit; signal synthesizing circuit synthesizing the other of the divided signals with the generated distortion signal; and signal amplifying circuit amplifying the synthesized signal and outputting an output signal, and wherein the signal adjusting circuit executes the predetermined adjustment such that there is a predetermined relationship between the level of a difference between the signal amplitudes of predetermined frequency components contained in a distortion signal and the level of a difference between the signal amplitudes of the predetermined frequency components contained in a distortion signal.

Abstract: A wireless communication base station system of the present invention includes a wireless key base station, an optical forward base station, and an optical transmitter which connects the wireless key base station and the optical forward base station to each other. An optical signal modulated by a signal component and that modulated by a distortion component are transmitted from the wireless key base station to the optical forward base station. In the optical forward base station, these optical signals are converted to high-frequency electrical signals, and the high-frequency signal consisting of the signal component is amplified. Thereafter, the amplified signal is combined with the high-frequency signal consisting of the distortion component with their phases opposite to each other, so that the distortion component include in the amplified signal is removed.

Abstract: A power amplifier capable of compensating for distortion by pre-distortion and achieving a large distortion suppressing effect even if IM3L components and IM3U components occurring at the power amplifier have a large level difference. A power amplifying circuit 117 amplifies an original signal. An envelope detector 119 generates an envelope signal having components identical to envelope components included in the original signal. Based on the original signal a distortion signal generating circuit 112 generates a distortion signal for canceling distortion components occurring while the original signal is amplified by the power amplifying circuit 117. In a power combiner 116, the envelope signal is injected to the original signal, thereby eliminating the asymmetric characteristic of the distortion components. In the power amplifying circuit 117, the distortion signal is injected to the original signal, thereby suppressing the distortion components.

Abstract: The conventional feedforward amplifier is unable to suppress distortion components efficiently. The present invention provides a feedforward amplifier wherein the vector adjustor is adjusted so that (1) suppression is performed on only the distortion component generated within a predetermined frequency range out of the range of frequencies to be suppressed in which distortion components to be suppressed occur or (2) the suppression of the distortion component generated within the predetermined frequency range is greater than the suppression of the distortion component generated within the frequency range other than the predetermined frequency range out of the range of frequencies to be suppressed, and the pre-distortion circuit is adjusted so that at least the distortion component generated within the frequency range other than the predetermined frequency range is suppressed.

Abstract: A power amplifier capable of compensating for distortion by pre-distortion and achieving a large distortion suppressing effect even if IM3L components and IM3U components occurring at the power amplifier have a large level difference. A power amplifying circuit 117 amplifies an original signal. An envelope detector 119 generates an envelope signal having components identical to envelope components included in the original signal. Based on the original signal a distortion signal generating circuit 112 generates a distortion signal for canceling distortion components occurring while the original signal is amplified by the power amplifying circuit 117. In a power combiner 116, the envelope signal is injected to the original signal, thereby eliminating the asymmetric characteristic of the distortion components. In the power amplifying circuit 117, the distortion signal is injected to the original signal, thereby suppressing the distortion components.

Abstract: It is difficult that the impedance of the circuit part on the output side of an amplifying element at the frequency of a modulating wave is lower, and consequently, it is difficult to more effectively use the linearity of the amplifying element. The phase of a signal of the frequency of the modulating wave included in an amplified signal output from a FET is inverted by a difference frequency inverting circuit. The inverted signal of the frequency of the modulating wave and a signal of the frequency of a modulated wave included in an amplified signal output from a FET cancel each other out at the drain of the FET. At the drain end of the FET, the signal of the frequency of the modulating wave included in the amplified signal of the FET and a signal of the frequency of the modulating wave output from the FET cancel each other out.

Abstract: A power amplifier capable of compensating for distortion by pre-distortion and achieving a large distortion suppressing effect even if IM3L components and IM3U components occurring at the power amplifier have a large level difference. A power amplifying circuit 117 amplifies an original signal. An envelope detector 119 generates an envelope signal having components identical to envelope components included in the original signal. Based on the original signal a distortion signal generating circuit 112 generates a distortion signal for canceling distortion components occurring while the original signal is amplified by the power amplifying circuit 117. In a power combiner 116, the envelope signal is injected to the original signal, thereby eliminating the asymmetric characteristic of the distortion components. In the power amplifying circuit 117, the distortion signal is injected to the original signal, thereby suppressing the distortion components.

Abstract: A method of controlling a feedforward distortion compensation amplifier has steps of detecting a distortion component generated in a main amplifier by coupling a signal branched from a signal input to the main amplifier and containing a plurality of carriers of different frequencies to a signal branched from an output signal from the main amplifier so that the coupling causes the carrier components to cancel each other, recoupling the signal resulting from the coupling to the output signal from the main amplifier, and adjusting an amplitude and phase of at least one of the signals to be recoupled so that distortion components cancel each other upon recoupling, wherein a first and second pilot signals obtained from a first and second pilot signal sources are inserted into the input signal to or output signal from the main amplifier, parts of the signal resulting from the recoupling are taken out through branching, and the signals taken out through branching are mixed with the first and second pilot signals

Abstract: A power amplifier comprises an amplifier of amplifying a high-frequency signal modulated by an input signal, an inverted envelope generating circuit generating an inverted envelope signal by using the input signal or the high-frequency signal, the inverted envelope signal having an inverted envelope, a gain variable amplifier adjusting amplitude of the inverted envelope signal, a variable delay circuit adjusting a phase of the inverted envelope signal, and a control circuit outputting a control signal to the gain variable amplifier and the variable delay circuit based on information about distortion or a signal level of the amplified high-frequency signal. The inverted envelope signal having been adjusted in amplitude or phase is injected to the high-frequency signal or the amplified high-frequency signal, and the control circuit controls the gain variable amplifier or the variable delay circuit so that distortion or a signal level of the amplified high-frequency signal is minimum.

Abstract: The conventional feedforward amplifier is unable to suppress distortion components efficiently. The present invention provides a feedforward amplifier wherein the vector adjustor is adjusted so that (1) suppression is performed on only the distortion component generated within a predetermined frequency range out of the range of frequencies to be suppressed in which distortion components to be suppressed occur or (2) the suppression of the distortion component generated within the predetermined frequency range is greater than the suppression of the distortion component generated within the frequency range other than the predetermined frequency range out of the range of frequencies to be suppressed, and the pre-distortion circuit is adjusted so that at least the distortion component generated within the frequency range other than the predetermined frequency range is suppressed.

Abstract: Provided is a distortion-compensated amplifying circuit capable of suppressing distortion without attenuating a level of carrier components, and further obtaining a larger amount of suppression of distortion, which has not been achievable by conventional distortion-compensated amplifying circuit using a pre-distortion technique. A balanced type amplifying circuit is structured such that amplifiers 115 and 116 placed in parallel are sandwiched by 90-degree hybrid circuits 114 and 117. The 90-degree hybrid circuit 114 is supplied with an original signal including carrier components and a distortion signal including distortion equal in amplitude and opposite in phase (having a phase difference of 180 degrees) to distortion that occurs when the original signal is amplified by the amplifiers 115 and 116. The 90-degree hybrid circuit 114 performs a process of differential amplification with a phase difference of 180 degrees between the original signal and the distortion signal.

Abstract: A feedforward amplifier includes a first power splitter for dividing an input signal into two paths. The first path, in sequence, includes a first vector adjuster, a main amplifier, a second power splitter and a delay circuit. The second path, in sequence, includes a delay circuit, a distortion detecting power combiner, a second vector adjuster and an error amplifier. The distortion detecting power combiner combines a portion of a signal from the first path with a signal in the second path. Each vector adjuster adjusts amplitude and phase of a signal in each path. A distortion suppression power combiner synthesizes a signal in the first path with a signal in the second path. Control is included for stopping operation of the error amplifier or main amplifier based on a predetermined condition.

Abstract: A wireless communication base station system of the present invention includes a wireless key base station, an optical forward base station, and an optical transmitter which connects the wireless key base station and the optical forward base station to each other. An optical signal modulated by a signal component and that modulated by a distortion component are transmitted from the wireless key base station to the optical forward base station. In the optical forward base station, these optical signals are converted to high-frequency electrical signals, and the high-frequency signal consisting of the signal component is amplified. Thereafter, the amplified signal is combined with the high-frequency signal consisting of the distortion component with their phases opposite to each other, so that the distortion component include in the amplified signal is removed.

Abstract: A power amplifier capable of compensating for distortion by pre-distortion and achieving a large distortion suppressing effect even if IM3L components and IM3U components occurring at the power amplifier have a large level difference. A power amplifying circuit 117 amplifies an original signal. An envelope detector 119 generates an envelope signal having components identical to envelope components included in the original signal. Based on the original signal a distortion signal generating circuit 112 generates a distortion signal for canceling distortion components occurring while the original signal is amplified by the power amplifying circuit 117. In a power combiner 116, the envelope signal is injected to the original signal, thereby eliminating the asymmetric characteristic of the distortion components. In the power amplifying circuit 117, the distortion signal is injected to the original signal, thereby suppressing the distortion components.

Abstract: It is difficult that the impedance of the circuit part on the output side of an amplifying element at the frequency of a modulating wave is lower, and consequently, it is difficult to more effectively use the linearity of the amplifying element. The phase of a signal of the frequency of the modulating wave included in an amplified signal output from a FET is inverted by a difference frequency inverting circuit. The inverted signal of the frequency of the modulating wave and a signal of the frequency of a modulated wave included in an amplified signal output from a FET cancel each other out at the drain of the FET. At the drain end of the FET, the signal of the frequency of the modulating wave included in the amplified signal of the FET and a signal of the frequency of the modulating wave output from the FET cancel each other out.

Abstract: Provided is a distortion-compensated amplifying circuit capable of suppressing distortion without attenuating a level of carrier components, and further obtaining a larger amount of suppression of distortion, which has not been achievable by conventional distortion-compensated amplifying circuit using a pre-distortion technique. A balanced type amplifying circuit is structured such that amplifiers 115 and 116 placed in parallel are sandwiched by 90-degree hybrid circuits 114 and 117. The 90-degree hybrid circuit 114 is supplied with an original signal including carrier components and a distortion signal including distortion equal in amplitude and opposite in phase (having a phase difference of 180 degrees) to distortion that occurs when the original signal is amplified by the amplifiers 115 and 116. The 90-degree hybrid circuit 114 performs a process of differential amplification with a phase difference of 180 degrees between the original signal and the distortion signal.

Abstract: An antenna for mobile wireless communications in which two built-in antennas 101, 102 having a bisymmetric shape arranged in an axi-symmetric location of a ground plate 105 and, by feeding both of the antennas by using a balanced-to-unbalanced conversion circuit 106 at the same amplitude and the phase difference of 180 degrees, balanced operations are performed.

Abstract: A power amplifier that reduces intermodulation distortion generated by the amplifier while reducing the number of parts is provided. A power amplifier comprises a first balun, to which a combined signal combining two signals of different frequencies is inputted, and which outputs, based on the combined signal, the first and the second signal whose phase are opposite; a first amplifier that outputs the first amplified signal containing the differential frequency component comprising the difference of the frequencies of two signals from the first signal; a second amplifier that outputs the second amplified signal containing the component comprising the difference of the frequencies of two signals from the second signal; and a second balun that outputs the combined signal of the first and the second amplified signals. The component contained in the first and the second amplified signal are inputted via the second and the first amplifier, respectively, to reduce the component.

Abstract: A method of controlling a feedforward distortion compensation amplifier has steps of