Abstract: A superconducting signal transmission apparatus provided with a vacuum container 11, a superconducting electronic device 12 provided in the vacuum container 11, an input side transmission line 13 and output side transmission line 14 for connection to the superconducting electronic device 12 through the vacuum container 11, and a cooling mechanism (15, 16, 17) for cooling the superconducting electronic device 12 and further having a heat cutoff signal transmission unit 20 inserted at least at part of the input side and output side transmission lines 13 and 14. The heat cutoff signal transmission unit 20 is comprised of a substrate 31 and a flat circuit body 30 provided with a signal transmission line 32 and ground layer (33, 33-1, 33-2). The substrate 31 is comprised of a dielectric material having a small heat conductivity. The conductor portions forming the signal transmission line 32 and the ground layer are formed with thin thicknesses enabling suppression of the inflow of heat from the outside.

Abstract: The purpose of the present invention is to compensate the distortion of an amplifier by a predistorter which compensates the distortion of a power amplifier even when a frequency amplitude deviation exists. The predistorter comprises a distortion compensation coefficient storage unit for storing a distortion compensation coefficient corresponding to the reference value using the characteristic quantity of the envelope of a transmission signal before being inputted to the power amplifier as a reference value; and a reference value conversion unit for converting the characteristic quantity into a predetermined value according to the size of the characteristic quantity, and when the characteristic quantity is, for example, the amplitude value of an envelope and the amplitude value is small, that value is rounded up, for example, to an upper-limit value within a linear range of the amplifier.

Abstract: The distortion compensator which compensates the nonlinearity of a power amplifier in a radio communication device stops the operation of updating the automatic phase adjustment, automatic delay adjustment, equalizer adjustment, and distortion compensation table when something wrong is detected in the input to a distortion compensation unit such as a reference signal, feedback signal, address of the distortion compensation table, and phase value so that the distortion compensation coefficients may not be improperly updated.

Abstract: The present invention relates to superconductive filter technology. According to the arrangement of the superconductive filter (1), a columnar resonating member (23) having a superconductive material formed on the surface thereof is attached at one of its ends thereof to an inner wall (22) of a filter housing (21) so that a space is interposed between the columnar resonating member and each of connectors (27a, 27b) which are connectable to a signal input/output cables (5a, 5b), respectively. According to this arrangement, heat conduction from the outside can be suppressed as far as possible, and the superconductive condition can be created with stability, with the result that a stable filtering characteristic can be created.

Abstract: Disclosed is an adaptive control apparatus having an error calculation unit for calculating the difference between a reference signal and a feedback signal, and an adaptive controller for applying adaptive control so as to diminish the difference and causing the result of adaptive control to be reflected in the reference signal. The adaptive control apparatus has a delay unit for delaying at least one of the reference signal and feedback signal by a set delay time in such a manner that the reference signal and feedback signal will be input simultaneously to the arithmetic unit; a frequency-component detecting unit for detecting a frequency component of the reference signal; a delay-time acquisition unit for acquiring delay time conforming to the frequency component; and a delay-time setting unit for setting the acquired delay time in the delay unit.

Abstract: A distortion compensating apparatus calculates a distortion compensation coefficient in such a manner that a difference signal between a reference signal, which is a transmit signal, and a feedback signal will be diminished, updates an old distortion compensation coefficient by the calculated distortion compensation coefficient and applies distortion compensation to the transmit signal based upon this distortion compensation coefficient. In this apparatus, a phase correcting interval, which is for correcting the phase difference between the reference signal and the feedback signal, and a distortion compensation coefficient updating interval are generated alternately, a correction is applied so as to null the phase difference in the phase correcting interval, and the distortion compensation coefficient is updated in the distortion compensation coefficient updating interval.

Abstract: A superconducting microstrip filter capable of achieving an improvement of power resistance without enlarging the overall size and while maintaining steep cut characteristics. This filter has a resonator section including at least one resonator. This resonator forms a current density reduction part in one part of its line pattern. Also, the filter has an input line section arranged adjoining the resonator of an initial stage. Current density reduction parts are formed in one part of this input line section. Alternatively, the input line section is comprised of a normal conductor.

Abstract: A radio comprises a power amplifier for amplifying a signal to be transmitted; a distortion compensation table storing distortion compensation coefficients for compensating a distortion of the power amplifier; a computing unit for updating the distortion compensation coefficient based on a difference between a transmission input signal and a transmission output signal; a bias voltage controller for applying a bias voltage to the power amplifier, said bias voltage determined based on a transmit control signal so as to maximize a power efficiency of the power amplifier.

Abstract: An input complex base band signal x(t) is complex-multiplied by a distortion compensation coefficient h(p), quadrature-modulated by a quadrature modulator QMOD, and input into a power amplifier AMP. A part of the output from the power amplifier AMP is input into a band pass filter BPF, the band pass filter BPF extracts an adjacent channel leakage power band, and a power detector detects an adjacent channel leakage power value. A distortion compensation coefficient arithmetic unit GA using a genetic algorithm computes a distortion compensation coefficient based on an adjacent channel leakage power value on an adjacent channel leakage power ratio and an input complex base band signal x(t), and outputs a distortion compensation coefficient h(p) as a function of a power value p of the input complex base band signal.

Abstract: In order to linearize the input/output characteristic of a power amplifier, a pre-distortion is performed using a pre-distortion function obtained from the inverse function of the input/output characteristic, in which the inclination of the highly linear low power part of this input/output characteristic is maintained. When the pre-distortion function is digitized and stored in a table, a differential between the pre-distortion function and a function of y=x is obtained, and a function table indicating this differential is stored. Since the gently inclined part of the pre-distortion function equals a function y=x, it is sufficient if only the difference between the input signal and function y=x is digitized, thereby realizing the reduction of the quantization error.

Abstract: Disclosed is a superconducting filter apparatus having a refrigerator for cooling the superconducting filter to cryogenic temperatures, a pilot signal generator for generating a pilot signal that is outside the pass band and inputting the pilot signal to the superconducting filter together with an antenna receive signal, and a discriminating unit for discriminating abnormality in the refrigerator. If the refrigerator malfunctions and temperature of the superconducting filter rises, the pass band of the superconducting filter shifts to the low-frequency side and crosses the frequency of the pilot signal. The pilot signal passes through the superconducting filter at this time. The discriminating unit discriminates abnormality in the refrigerator based upon the pilot signal contained in the output of the superconducting filter.

Abstract: An input complex base band signal x(t) is complex-multiplied by a distortion compensation coefficient h(p), quadrature-modulated by a quadrature modulator QMOD, and input into a power amplifier AMP. A part of the output from the power amplifier AMP is input into a band pass filter BPF, the band pass filter BPF extracts an adjacent channel leakage power band, and a power detector detects an adjacent channel leakage power value. A distortion compensation coefficient arithmetic unit GA using a genetic algorithm computes a distortion compensation coefficient based on an adjacent channel leakage power value or an adjacent channel leakage power ratio and an input complex base band signal x(t), and outputs a distortion compensation coefficient h(p) as a function of a power value p of the input complex base band signal.

Abstract: A distortion compensation apparatus and method for a power amplifier enable accurate distortion compensation, even if frequency amplitude deviation and group delay error are present in the power amplifier. A reverse distortion coefficient is read from a reverse distortion coefficient table. A distortion compensation process is performed on an incoming signal using the read reverse distortion coefficient. The distortion compensated signal is amplified and transmitted by the power amplifier, and the reverse distortion coefficient table is updated based on the incoming signal before distortion compensation, and the output signal of the power amplifier. The relation between the phase of the time difference value and the reverse distortion coefficient is obtained from the reverse distortion coefficient corresponding to a linear operation domain of the power amplifier.

Abstract: In the mobile communication, a distortion compensation amplifying apparatus is provided.

Abstract: A superconducting microstrip filter capable of achieving an improvement of power resistance without enlarging the overall size and while maintaining steep cut characteristics. This filter has a resonator section including at least one resonator. This resonator forms a current density reduction part in one part of its line pattern. Also, the filter has an input line section arranged adjoining the resonator of an initial stage. Current density reduction parts are formed in one part of this input line section. Alternatively, the input line section is comprised of a normal conductor.

Abstract: A superconducting signal transmission apparatus provided with a vacuum container 11, a superconducting electronic device 12 provided in the vacuum container 11, an input side transmission line 13 and output side transmission line 14 for connection to the superconducting electronic device 12 through the vacuum container 11, and a cooling mechanism (15, 16, 17) for cooling the superconducting electronic device 12 and further having a heat cutoff signal transmission unit 20 inserted at least at part of the input side and output side transmission lines 13 and 14. The heat cutoff signal transmission unit 20 is comprised of a substrate 31 and a flat circuit body 30 provided with a signal transmission line 32 and ground layer (33, 33-1, 33-2). The substrate 31 is comprised of a dielectric material having a small heat conductivity. The conductor portions forming the signal transmission line 32 and the ground layer are formed with thin thicknesses enabling suppression of the inflow of heat from the outside.

Abstract: In the mobile communication, a distortion compensation amplifying apparatus is provided.

Abstract: Distortion compensation coefficients for correcting distortion of a transmission power amplifier are stored in a memory beforehand, a distortion compensation coefficient conforming to powers or amplitudes of a present transmit signal and a past transmit signal is read out of the memory, and distortion compensation processing is applied to the transmit signal using this distortion compensation coefficient. The transmit signal thus subjected to distortion compensation processing is then amplified by the transmission power amplifier and the amplified signal is transmitted, and the distortion compensation coefficient is updated based upon the transmit signal before distortion compensation and an output signal from the transmission power amplifier.

Abstract: The present invention relates to superconductive filter technology. According to the arrangement of the superconductive filter (1), a columnar resonating member (23) having a superconductive material formed on the surface thereof is attached at one of its ends thereof to an inner wall (22) of a filter housing (21) so that a space is interposed between the columnar resonating member and each of connectors (27a, 27b) which are connectable to a signal input/output cables (5a, 5b), respectively. According to this arrangement, heat conduction from the outside can be suppressed as far as possible, and the superconductive condition can be created with stability, with the result that a stable filtering characteristic can be created.

Abstract: In a predistorter, an input signal to be inputted into an amplifier is in advance modified by a reverse characteristic of an input-to-output characteristic of the amplifier. The predistorter determines correction coefficients corresponding to one or both of a differential and an integral of the input signal so as to further modify the input signal into a final predistortion signal according to the modified input signal and the correction coefficients.