Abstract: To reduce the size of a multi-carrier transmitter circuit for a mobile communication base station, by suppressing instantaneous peak output power to a small value with respect to a wide-band signal of a few MHz to tens of MHz so that the peak factor of a multi-carrier signal is reduced.

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: A balun design incorporating the functions of a splitter (combiner) which can be employed in a high power amplifier circuit configuration. The balun is formed of a dielectric multilayer board with conductor patterns on each conductor pattern layer. The balun includes the propagation of a half of an input signal to an in-phase output terminal, and also propagating a fourth of the input signal to first and second opposite-phase output terminals, the signal propagated to the first and second opposite-phase output terminals lagging 180 degrees behind the signal propagated to the in-phase output terminal. The balun provides the output signals at the first and second opposite-phase output terminals 180° out of phase employing through holes in the main line and coupling lines for promoting electromagnetic coupling therebetween.

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: The invention relates to a high frequency switch used in a communication apparatus or the like, such as a portable terminal. The switch includes a first signal terminal, a first diode, the cathode of which is directly or indirectly connected to the first signal terminal, a bias controlling device having an end which is connected to the anode of the first diode, a second signal terminal directly or indirectly connected to the anode of the first diode, an impedance converting device having an end which is directly or indirectly connected to the first signal terminal, a serial circuit having a high frequency voltage dividing device and a second diode, the serial circuit being connected to the other end of the impedance converting device, and a third signal terminal directly or indirectly connected to the other end of the impedance converting device.

Abstract: A feedforward amplifier has

Abstract: (Object)

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

Abstract: A delay circuit in which amplitude characteristic and delay time characteristic of the output signals do not have any ripple relative to the length of the transmission line is provided. The delay circuit includes a circuit that makes a part of signals distributed into two parts by the power divider (103) to be identical in amplitude and inverse in phase relative to the component of signals outputted from the terminal-a directly to the terminal-c of the circulator (104). By composing with the power combiner (107) both signals are offset each other at the output terminal. As a result, only the signals that are inputted from the input terminal (101) and transmitted through the circulator (104) and the open-ended transmission line (105) are outputted to the output terminal (102).

Abstract: A predistortion linearizer has

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 high power amplifier has a first balun propagating a half of an input signal to an in-phase output terminal, and also propagating a fourth of the input signal to first and second opposite-phase output terminals, the signal propagated to the first and second opposite-phase output terminals lagging 180 degrees behind the signal propagated to the in-phase output terminal; first and second power amplifier circuits connected to the first and second opposite-phase output terminals of the first balun and having the same characteristics;a third power amplifier circuit connected to the in-phase output terminal of the first balun and having output power substantially twice as much as the output power of the first or second power amplifier circuit; and a second balun having first and second opposite-phase input terminals for receiving the outputs of the first and second power amplifier circuits, having an in-phase input terminal for receiving the output of the third power amplifier circuit, combining the outputs of th

Abstract: The present invention concerns a radio circuit including a local oscillator, a first receive frequency converter, a frequency divider and a demodulator. A receive signal and an output of the local oscillator are input to the first receive frequency converter. The receive signal is converted into a first intermediate signal by the first receive frequency converter, and the first intermediate frequency signal is input to the demodulator. The output of the local oscillator is frequency-divided by the frequency divider and also input to the demodulator. The signal converted into the first intermediate frequency is demodulated into a baseband signal by the demodulator.

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 power amplifier has an input terminal; an output terminal; an N number of bypassable amplification circuits which are connected directly or indirectly in a sequential manner between the input terminal and the output terminal; an impedance conversion circuit which is connected directly or indirectly between the amplification circuit of a final stage and the output terminal; and a bias control circuit which controls the amplification circuits, each of the amplification circuits is configured by a high-frequency switch circuit, and an amplifier which is connected directly or indirectly to the switch circuit, and the bias control circuit controls power source voltages of the amplifiers and controls status of the switch circuit.

Abstract: An amplitude frequency characteristic adjustment circuit 106 is provided downstream of and connected to a distortion generation circuit 105. An amplitude difference between low-frequency-side and high-frequency-side distortion voltages is adjusted by the amplitude frequency characteristic adjustment circuit 106, and then their amplitudes and phases are adjusted by a vector adjustment circuit 107. This configuration makes it possible to suppress simultaneously both of low-frequency-side and high-frequency-side distortion voltages of a distortion generated by a wide-band class-AB power amplifier even if they are different in amplitude and phase.

Abstract: A feedforward amplifier includes a power divider for dividing the input signal into first and second signals. The first signal is processed in a first path that includes, in sequence, a first vector adjuster, a main amplifier, a directional coupler and a delay circuit. The second signal is delayed in a second path that includes, in sequence, another delay circuit, a first power combiner and an auxiliary amplifier block. The first power combiner combines the first signal, by way of a coupling port from the directional coupler, with the second signal to provide a combined signal into the auxiliary amplifier block. The auxiliary amplifier block further divides the second signal into two divided signals, each having a respective non-overlapping frequency band. The two divided signals are respectively vector adjusted, amplified, and then recombined. The recombined signal is then recombined with the processed signal in the first path to provide the desired output signal.

Abstract: According to the configuration the present power splitter, it is possible to reduce the characteristic impedance of a transmission line constituting a directional coupler by setting the impedance of a first terminal pair constituted of an input port 7a and a second output port 7d of a 6-dB branch-line-shaped directional coupler 7 to a value smaller than a reference impedance Z0 (50 &OHgr; in general) and setting the impedance of a second terminal pair constituted of an isolation port 7b and a first output port 7c of the directional coupler 7 to Z0. Therefore, it is possible to increase the number of splits and reduce loss, as compared with conventional cases.

Abstract: A predistortion circuit has