Abstract: First, a digital section constituting a linearizer is activated. Then, a feedback loop for updating a distortion compensation coefficient is opened. Then, the analog section on the antenna side is activated from an ADC, including a PA, etc., or a DAC. Then, both the ATT value of an ATT installed in a feedback route for updating the distortion compensation coefficient and the signal delay amount of a signal delay unit are adjusted to make a state such that the distortion compensation coefficient can be accurately updated. Then, the feedback loop is closed, a distortion compensation table having the distortion compensation coefficient as an entry is generated and after the generation is completed, the operation shifts to the normal operation.

Abstract: Disclosed is a method of controlling direction of radio-wave emission of a base-station transmitter which emits radio waves upon providing the radio waves with directivity in the direction of a receiver. Two antennas of a base station that are disposed at different positions transmit first and second signals that have been spread by mutually orthogonal spreading codes. A mobile station has a phase detector for receiving the first and second signals transmitted from respective ones of the antennas and obtaining a phase difference between these signals, and a direction estimator for calculating the direction of the mobile station, as seen from the base station, based upon the phase difference and for feeding back a signal representing the calculated direction from the mobile station to the base station. The transmitter of the base station transmits data toward the receiver in the calculated direction using a directional antenna.

Abstract: Disclosed is a distortion compensating apparatus for correcting the size of a distortion compensation coefficient in such a manner that a transmit signal that has undergone distortion compensation will not exceed the dynamic range of a DA converter. Specifically, before a distortion compensation coefficient hn+1(p) that has been calculated by a calculation unit is stored in a coefficient memory, an assumption is made that distortion compensation will be performed using the distortion compensation coefficient hn+1(p). Then it is determined beforehand whether a signal x(t)*hn+1(p) that will be obtained by this distortion compensation will exceed the limit of a DA converter. If the limit will be exceeded, the size of the distortion compensation coefficient is reduced by a correction unit, the corrected distortion compensation coefficient is stored in the memory and the transmit signal is corrected using the stored distortion compensation coefficient.

Abstract: A distortion compensating apparatus for compensating for a distortion of a transmission power amplifier. A delay time decision unit calculates the correlation between a transmission signal and a feedback signal fed back from the output side of the transmission power amplifier while varying phase difference between both signals, and decides the total delay time caused in the transmission power amplifier and a feedback loop on the basis of the phase difference in which the correlation is the maximum. A delay unit delays the transmission signal before a distortion compensation processing by the total delay time, and inputs the delayed signal into a distortion compensating apparatus arithmetic unit, which calculates and stores a distortion compensation coefficient on the basis of the transmission signal and the feedback signal fed back from the output side of the transmission power amplifier.

Abstract: There are disclosed a radiocommunication apparatus and a radiocommunication system. There are provided a receiving section capable of receiving a plurality of types of signals which have been spread through use of different spread code information according to a CDMA scheme in a transmitting-side radiocommunication apparatuses; and a spread demodulation section which carries out despread processing for the common signal portions of the plurality of types of signals received by the receiving section through use of a composite spread code formed from a plurality of spread codes. Accordingly, it becomes possible to significantly improve the quality of received signals.

Abstract: A mobile station is provided which does not cause a reduction in the speech transmission capacity. Branches receive radio signals from base stations and operate independently of one another. A branch operation control section controls the operation of the individual branches to detect a destination-side base station based on the reception levels of signals from surrounding base stations, to cause part of the branches to establish synchronization of spreading code and carrier frequency with respect to the destination-side base station while causing the other part of the branches to maintain communication with a departure-side base station after the destination-side base station is detected, and to cut off the communication with the departure-side base station after the synchronization is established.

Abstract: A code multiplexing transmitting apparatus spread-spectrum modulates transmission data of a plurality of channels by spreading codes that differ from one another, combines the spread-spectrum signals of each of the channels and transmits the resultant spread-spectrum modulated signal. A spread-spectrum modulating unit for each channel includes a phase shifter for shifting, by a predetermined angle channel by channel, the phase of a position vector of the spread-spectrum modulated signal of each channel. As the result of such phase control, the phases of pilot signal portions of the spread-spectrum modulated signals of the respective channels are shifted relative to one another so that the peak values of the code-multiplexed signal can be suppressed.

Abstract: Disclosed is a radio apparatus in which modulating signals (I, Q signals) from an arithmetic/control unit are converted to analog signals, which are then applied to an orthogonal modulator. A modulated wave for transmission, which has been produced by orthogonally modulating a reference carrier wave by the modulating signals, is demodulated by the orthogonal detector. The arithmetic/control unit compares the modulating signals and the demodulated signals and, based upon the comparison, updates distortion compensation coefficients and applies pre-distortion processing to the modulating signal using the distortion compensation coefficients. Leakage carrier produced due to offset of the orthogonal modulator is detected and the arithmetic/control unit adjusts the level of the modulating signals or shifts the phase of the reference carrier wave in such a manner that the leakage carrier (offset) becomes zero.

Abstract: A radio receiver includes a plurality of demodulating units for demodulating a received radio wave received via a plurality of paths so as to produce respective demodulated signals, and combining units for executing a combination process of synchronizing and combining the demodulated signals produced by the plurality of demodulating units, the combining units correlating the demodulated signals produced by the plurality of demodulating units and excluding from a combination process a demodulated signal that meets a predetermined condition based on a predetermined algorithm.

Abstract: Co-channel interference may be prevented even if data having different transmission rates are concurrently multiplied to a same frequency band width with a different spreading factors.

Abstract: SIR measurement for measuring S/N ratio, which is the ratio of a desired signal power to noise power, or S/I ratio, which is the ratio of desired signal power to interference signal power, uses a signal-point position altering unit for taking absolute values of an I component (in-phase component) and Q component (quadrature component) of a received signal to convert the received signal to a signal in the first quadrant of an I-Q orthogonal coordinate system, and for squaring the average value of the converted signal to obtain first average power (desired power) S, a received-power arithmetic unit for calculating the average value of the square of the received signal to obtain second average power, and for subtracting the desired power S from the received power to obtain noise power or interference power I, and a SIR arithmetic unit for calculating S/N ratio or S/I ratio from the desired signal power S and noise power or interference signal power I, and for outputting the ratio calculated.

Abstract: A plurality of chips generated by spectrum spreading from each of the bits constituting transmission information are distributed along the time axis, and transmitted. At the receiving end, the transmission information is recovered while integrating information of the chips distributed along the time axis. In a first aspect of the present invention, the transmission information is repeated multiple times, and then the resulting information is spread by a spreading code to generate the transmission data. In a second aspect of the present invention, the transmission information is first spread by a spreading code and then interleaved to generate the transmission data.

Abstract: A code multiplexing wireless apparatus for amplifying a code-multiplexed signal and then transmitting the amplified signal includes the following to reduce output back-off, improve the efficiency of a power amplifier and suppress broadening of the frequency spectrum: (1) a code-multiplexed signal generator for multiplying each item of transmission data by a spreading code sequence and combining spread-spectrum modulated signals to generate a code-multiplexed signal, (2) a signal-peak suppressing unit for holding the envelope of the code-multiplexed signal below a set level, and (3) a power amplifier for amplifying the code-multiplexed signal and transmitting the amplified code-multiplexed signal from an antenna.

Abstract: A amplifier having distortion compensation is employed as a power amplifier for amplifying a linear modulated signal or a low noise amplifier for amplifying a linear modulated signal. The amplifier having distortion compenssation includes an amplifier circuit for amplifying an input signal; an error detecting circuit for obtaining an error signal between the input signal to and an output signal from the amplifier circuit; a coefficient generating circuit for generating compensation coefficients to compensate distortion components of characteristics of the amplifier circuit, based on the error signal according to an adaptive type algorithm; a first outputting circuit for outputting a generated compensation coefficient corresponding to the input signal; and a multiplying circuit for multiplying the generated compensation coefficient to the input signal and inputting a multiplied coefficient to the amplifier circuit.

Abstract: A waveform equalizer for equalizing a distorted signal, contains a sampling unit, a time series generating unit, and an equalization neural network unit. The sampling unit samples the level of a distorted signal at a predetermined rate. The time series generating unit serially receives the sampled level and outputs in parallel a predetermined number of the levels which have been last received. The equalization neural network unit receives the outputs of the time series generating unit, and generates an equalized signal of the distorted signal based on the outputs of the time series generating unit using a set of equalization network weights which are preset therein. The waveform equalizer may further contain a distortion characteristic detecting unit, an equalization network weight holding unit, and a selector unit. The distortion characteristic detecting unit detects a distortion characteristic of the distorted signal.

Abstract: An FSK demodulation circuit which receives as input an FSK modulated reception signal, obtains two quadrature pulse trains, i.e., a first pulse train and a second pulse train, from a phase detection circuit, is provided with at least two sampling means which use the edge of one of the pulse trains and sample the logic of the other pulse train, produces two or more sample outputs at different timings, and determines the logic of the reproduced data from a combination of the logics "1" and "0" of the sample outputs.

Abstract: A catalyst for hydrotreating a heavy hydrocarbon oil which comprises a porous refractory inorganic oxide carrier component and at least one hydrogenating active metal component selected from nickel, cobalt and the like, the metal component concentration in the cross-section of the catalyst being the highest between the center of the cross-section and the periphery thereof.

Abstract: The present invention provides a method for removing an iron content in a petroleum series mineral oil therefrom which comprises treating a petroleum series mineral oil fraction containing 5 ppm or more of the iron content by the use of a high gradient magnetic separator under conditions of the strength of a magnetic field being from 500 to 25,000 gauss, a temperature being from room temperature to 400.degree. C., and a linear velocity being 0.1 to 50 cm/second.

Abstract: The present invention provides a catalyst for hydrotreatment of heavy oils in which at least one active metal component for hydrogenation selected from the Groups Vb, VIb and VIII of the periodic table is supported in a porous refractory carrier, the catalyst being characterized in that a distribution of the metal concentrative in each catalyst satisfies the relation of Cr.sub.1 <Cr.sub.2 in the case of R.sub.1 >R.sub.2 in the sectional surface of said catalyst, and a method for preparing the catalyst.

Abstract: A process for catalytic reaction of heavy oils and a particulate solid medium, which comprises withdrawing a part or the whole of the used medium from the reactor, separating the withdrawn particles into the particles which have been rendered magnetic by the deposition thereon of nickel, vanadium, iron and copper originally contained in the heavy oils, and non-magnetic particles, using a high gradient magnetic separator which is so designed that a ferromagnetic matrix is placed in a uniform high magnetic field, and returning the non-magnetic particles of the medium into the reactor for re-use.