Abstract: A predistortion distortion signal generating unit uses a signal to be amplified to generate a predistortion distortion signal including odd-order signal components of the signal. A delay time difference adjusting unit adjusts a delay time difference between a signal to be amplified and a distortion signal for predistortion such that an influence by the memory effect occurring in the amplifier can be reduced. A predistortion distortion signal giving unit gives a predistortion distortion signal to a signal to be amplified in a form that the delay time difference is adjusted.

Abstract: A peak limiter for use in a system for amplifying a multi-carrier signal receives a baseband signal of each carrier of the multi-carrier signal. The multi-carrier signal is computationally estimated to have carriers combined in an RF band, and obtains power information of the multi-carrier signal to limit an amplitude of the baseband signal based on the power information of the estimated multi-carrier signal to thereby provide peak-limited baseband signals. Thus, the distortion generated by performing the unnecessary peak limitation can be effectively prevented to thereby improve the reliability of the entire system.

Abstract: To update the control value to a value of higher precision in a predistortion type distortion compensation apparatus for compensating the distortion occurring in an amplifier for amplifying an input signal by the control using a control value corresponding to the level of the input signal.

Abstract: To provide an amplifying device with reduced size, weight and cost. The amplifying device delays input signals using digital delay sections in a main signal system, performs offset rotation processing of digital input signals in carrier offset sections and power detection in a power detecting section in a control system, matches phases of a multi-carrier signal of the main signal system and a power value signal of the control system in a phase control section, and gives distortion compensation in a predistorter for canceling a nonlinear characteristic generated in an amplifier.

Abstract: A memory effect distortion component compensating unit compensates for a distortion component caused by the memory effect of the amplifier by using a time difference of results from raising an input signal to even power.

Abstract: A distortion compensator that compensates for distortion arising in a main amplifier 10 that amplifies a signal effectively compensates for third order distortion which is unbalanced between the higher frequency band and lower frequency band. An amplitude detector 3 detects the level of a signal subject to amplification and a signal level change direction detection means 7 detects the direction of change in the level of the signal. A signal level change control means 4-8 stores the correspondence between the signal level and the mode of changing the signal in order to compensate for distortion for when the direction of change in the signal level is positive and when it is negative, and controls a signal change means 9 so that the amplitude and phase of the signal is changed in a mode of changing the signal corresponding to the detected direction of change in the signal level and the detected signal level.

Abstract: A distortion compensation circuit reduces an unbalance between higher and lower 3rd order distortions, the distortions being generated by an amplifier which amplifies an input signal having at least two frequency components. Amplitude modulation means, which includes an amplitude detector, an amplitude circuit, a phase circuit and another amplitude circuit, generates sideband signals corresponding to an instantaneous phase difference between the higher and lower 3rd order distortions, such that distortions generated by the amplifier can be cancelled. Further, sideband signal generating means, which includes an amplitude circuit, a delay circuit, an AM modulator, another amplitude circuit, another delay circuit and a PM modulator, performs AM and PM on the input signal to thereby generate sideband signals, such that distortions generated by the amplifier can be cancelled.

Abstract: This invention is intended to improve the efficiency of distortion compensation in a distortion compensator that compensates for distortion arising in an amplifier that amplifies a signal. Signal level detection means 1 detects the level of a signal amplified by the amplifier 5. Distortion compensation execution means 2-4 executes distortion compensation with respect to the signal amplified by the amplifier 5 by a mode of distortion compensation corresponding to the signal level detected by the signal level detection means based on a correspondence between signal levels and distortion compensation control values that determines the mode of distortion compensation. Distortion compensation control value correspondence update means 6 updates the correspondence between signal levels and distortion compensation control values used in the execution of distortion compensation by the distortion compensation execution means based on the signal amplified by the amplifier.

Abstract: A distortion reducing circuit compensates an upper side third-order distortion and a lower side third-order distortion produced by an amplifier for amplifying a fundamental signal including multiple frequency components. The distortion reducing circuit includes a second harmonic reflection coefficient regulation circuit, installed at an output side of the amplifier, for regulating reflection coefficients for multiple frequency components included in a second harmonic signal to have a constant value.

Abstract: There is provided a distortion canceling circuit for reducing an unbalance between a higher and a lower 3rd order distortion at frequencies of (2·f2−f1) and (2·f1−f2), respectively, the distortions being generated by an amplifier which amplifies an input signal having at least two frequency components, i.e., f1 and f2. Phase modulation control means supply a control signal, which has a difference frequency of (f2−f1), to phase modulation means, the control signal being generated based on the amplified input signal outputted from the amplifier. The phase modulation means performs phase modulation on the amplified input signal based on the supplied control signal to thereby generate a higher and a lower side-band signal having frequencies of (2·f2−f1) and (2·f1−f2), respectively, each of which has an identical amplitude and a phase difference of 180° with respect to each other.

Abstract: A distortion compensation amplification apparatus for compensating distortion generated while amplifying a signal, includes a distributor for distributing an input signal to provide a first and a second outputs, a first delay means for delaying the first output through the use of a surface acoustic wave element, a compensation value generation circuit, responsive to the second output, for determining amplitude and phase compensation values to be used in compensating the distortion, a second delay means for delaying the compensation values according to a delay time of the first delay means, and a predistortion circuit for compensating the output of the first delay means in response to the delayed compensation values. And the second delay means includes at least one type of circuit among the type of an analog delay circuit and a digital delay circuit.

Abstract: A distortion compensator that compensates for distortion arising in a main amplifier 10 that amplifies a signal effectively compensates for third order distortion which is unbalanced between the higher frequency band and lower frequency band. An amplitude detector 3 detects the level of a signal subject to amplification and a signal level change direction detection means 7 detects the direction of change in the level of the signal. A signal level change control means 4-8 stores the correspondence between the signal level and the mode of changing the signal in order to compensate for distortion for when the direction of change in the signal level is positive and when it is negative, and controls a signal change means 9 so that the amplitude and phase of the signal is changed in a mode of changing the signal corresponding to the detected direction of change in the signal level and the detected signal level.

Abstract: A distortion compensation amplification apparatus for compensating distortion generated while amplifying a signal, includes a distributor for distributing an input signal to provide a first and a second outputs, a first delay means for delaying the first output through the use of a surface acoustic wave element, a compensation value generation circuit, responsive to the second output, for determining amplitude and phase compensation values to be used in compensating the distortion, a second delay means for delaying the compensation values according to a delay time of the first delay means, and a predistortion circuit for compensating the output of the first delay means in response to the delayed compensation values. And the second delay means includes at least one type of circuit among the type of an analog delay circuit and a digital delay circuit.

Abstract: A distortion reducing circuit compensates an upper side third-order distortion and a lower side third-order distortion produced by an amplifier for amplifying a fundamental signal including multiple frequency components. The distortion reducing circuit includes a second harmonic reflection coefficient regulation circuit, installed at an output side of the amplifier, for regulating reflection coefficients for multiple frequency components included in a second harmonic signal to have a constant value.

Abstract: A distortion compensation circuit reduces an unbalance between higher and lower 3rd order distortions, the distortions being generated by an amplifier which amplifies an input signal having at least two frequency components. Amplitude modulation means, which includes an amplitude detector, an amplitude circuit, a phase circuit and another amplitude circuit, generates sideband signals corresponding to an instantaneous phase difference between the higher and lower 3rd order distortions, such that distortions generated by the amplifier can be cancelled. Further, sideband signal generating means, which includes an amplitude circuit, a delay circuit, an AM modulator, another amplitude circuit, another delay circuit and a PM modulator, performs AM and PM on the input signal to thereby generate sideband signals, such that distortions generated by the amplifier can be cancelled.

Abstract: A distortion compensator for compensating for distortion produced in an amplifier that amplifies a signal includes a signal level detection means for detecting a level of a signal to be amplified and distortion compensation means for conducting distortion compensation based on the detection result separately for each frequency band signal of multiple frequency band signals contained in the signal to be amplified. The distortion compensator improves distortion compensation performance by reducing the effect of frequency characteristics that restrict the distortion compensation performance limit.

Abstract: To provide an amplifying device with reduced size, weight and cost. The amplifying device delays input signals using digital delay sections in a main signal system, performs offset rotation processing of digital input signals in carrier offset sections and power detection in a power detecting section in a control system, matches phases of a multi-carrier signal of the main signal system and a power value signal of the control system in a phase control section, and gives distortion compensation in a predistorter for canceling a nonlinear characteristic generated in an amplifier.

Abstract: To provide an amplifying device which is reduced in size, weight and cost and which can improve the distortion compensation performance. In the amplifying device, input signals are each subjected to digital orthogonal modulation using an IF and further to offset rotation processing in digital orthogonal modulators, then bifurcated into a main signal system and a control system, and detection of a power value is performed at an IF band in a power detecting section of the control system. Therefore, offset rotation processing of the input signals in the power detection is not required, so that a structure for matching phases of a multi-carrier signal and a power value signal is not required, resulting in improving the distortion compensation performance without using an analog delay line.

Abstract: A peak limiter for use in a system for amplifying a multi-carrier signal receives a baseband signal of each carrier of the multi-carrier signal. The multi-carrier signal is computationally estimated to have carriers combined in an RF band, and obtains power information of the multi-carrier signal to limit an amplitude of the baseband signal based on the power information of the estimated multi-carrier signal to thereby provide peak-limited baseband signals. Thus, the distortion generated by performing the unnecessary peak limitation can be effectively prevented to thereby improve the reliability of the entire system.

Abstract: There is provided a distortion canceling circuit for reducing an unbalance between a higher and a lower 3rd order distortion at frequencies of (2·f2−f1) and (2·f1−f2), respectively, the distortions being generated by an amplifier which amplifies an input signal having at least two frequency components, i.e., f1 and f2. Phase modulation control means supply a control signal, which has a difference frequency of (f2−f1), to phase modulation means, the control signal being generated based on the amplified input signal outputted from the amplifier. The phase modulation means performs phase modulation on the amplified input signal based on the supplied control signal to thereby generate a higher and a lower side-band signal having frequencies of (2·f2−f1) and (2·f1−f2), respectively, each of which has an identical amplitude and a phase difference of 180° with respect to each other.