Abstract: A multi-carrier signal received by an antenna is converted into a signal of an IF band by an RX, and converted into an I signal and a Q signal by an quadrature detector. The I signal and the Q signal as multi-carrier signals are converted into digital signals by an A/D converter, and input to complex filters. The complex filters extract a complex signal having a specified carrier. Then, complex filters shift the center frequency of the extracted complex signal into 0 Hz. The obtained base band signal is input to a finger, and despread and demodulated. The despread and demodulated signal is RAKE synthesized by a synthesis unit, and transmitted to a signal discrimination unit.

Abstract: The present invention is directed to a path searching device and a CDMA receiver employing the same, having a reduced circuit scale and operating to carry out a smaller number of operations. For a direct spreading CDMA communication system, a CDMA receiver includes a reception demodulator including an antenna, a high-frequency amplifier a band-pass filter, demodulators, etc. The CDMA receiver also has despreading units, a determination unit, and a path search device. The path search device has a sampling unit for sampling an input signal by low-speed oversampling based on an integer multiple of a chip rate and by high-speed oversampling that is faster than the low-speed oversampling, a first circuit for finding a correlative value between a spreading code and a signal provided by the low-speed oversampling and finding timing corresponding to a maximum correlative value.

Abstract: The present invention relates to a demodulator which receives a signal transmitted via phase modulation or multivalue QAM modulation, and decides transmitted data based on the received signal. The present invention enhances a transmission-line estimate by using tentatively decided data symbols as pilot symbols and in estimating a transmission line without a decrease in accuracy of transmission-line estimate even when an error rate of the tentatively decided data symbols is increased. The demodulator includes a pilot-based transmission-line estimation unit for estimating transmission-line characteristics by using pilot symbols. A tentative-data-decision unit for tentatively deciding data symbols based on the pilot-based transmission-line estimate. A data-based transmission-line estimation unit for estimating the transmission-line characteristics by using the tentatively decided data.

Abstract: An amusement system is provided wherein a variation of light intensity transmitted through a living body which reflects a metabolite concentration or concentration variation in the living body reflecting a mental state or brain activity, is measured, and the measurement result is reflected in an object displayed on a screen. By bringing a light illumination device and light detector in contact with the skin of a subject, the intensity of the light propagated in the subject is detected, and the detection result is transmitted to an electronic calculator. The position, shape or color of the object displayed on the screen is made to vary according to the variation of this detected intensity. Thus, human thought can be measured and the state of the object on the screen controlled without using an existing input device such as a mouse, joystick or handle.

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: In a semiconductor device having, at least, a first semiconductor layer which contains substantially no impurity, a second semiconductor layer which has a band gap greater than that of the first semiconductor layer and which contains an impurity, an interface between the first and second semiconductor layers forming a heterojunction, at least one pair of electrodes which are electronically connected with the first semiconductor layer, and means to control carriers developing at the heterojunction interface; a semiconductor device characterized in that the first semiconductor layer is a Ge layer, while the second semiconductor layer is a group III-V compound semiconductor layer.

Abstract: The semiconductor device of this invention consists at least of a laminate of a semi-insulating or p-type first semiconductor layer having a forbidden band width E.sub.g1, an undoped or p.sup.- -type second semiconductor layer having a forbidden band width E.sub.g2 and an n-type third semiconductor layer having forbidden band width E.sub.g3. The laminate is deposited on a predetermined semiconductor substrate and the forbidden band width has the relation E.sub.g2 <E.sub.g1, E.sub.g3. A pair of electrodes are so formed as to come into contact at least with the interface between the second and third semiconductor layers, and a control electrode, which forms a Schottky junction with the third semiconductor layer, is formed at a predetermined position interposed between the pair of electrodes. The semiconductor device has excellent pinch-off characteristic.

Abstract: A semiconductor laser having high efficiency of luminescence can be obtained by forming a spatial fluctuation of potential so that the potential differs from position to position inside a plane perpendicular to a current flowing direction and electrons and holes or excitons formed by a combination of them can be localized not only in the current flowing direction but also inside the plane perpendicular to the current flowing direction. More definitely, corrugations or ruggedness having a mean pitch of below 100 nm and a level difference of from 1/10 to 1/2 of the mean thickness of an active layer are formed on the surface of the active layer of the semiconductor laser.

Abstract: A semiconductor laser device comprises a semiconductor layer stack consisting of a first clad layer, an active layer, and a second clad layer which are successively stacked on a semiconductor substrate, and a light absorbing layer and a current blocking layer which are stacked on the second clad layer; the semiconductor assembly including a stripe shaped groove which extends from the surface of the semiconductor layer stack to the surface or interior of the second cladding layer, and another semiconductor layer having a forbidden band width greater than the active layer and the same conductivity type as the second clad layer which is embedded into the groove by chemical vapor deposition method.

Abstract: A semiconductor laser device is provided with an optical confinement region constituted by first, second, third and fourth semiconductor layers provided on the upper part of a predetermined semiconductor substrate in contact with each other successively. The first and fourth semiconductor layers are smaller in refractive index than the second and third semiconductor layers, and the third semiconductor layer is larger in refractive index than the second semiconductor layer. On the other hand, the second and fourth semiconductor layers are larger in forbidden bandwidth than the third semiconductor layer. At least the first and fourth semiconductor layers are opposite in conductivity type to each other. In addition to this, the optical confinement region is formed into a mesa-stripe, and both side walls of this mesa-stripe which are substantially parallel to the traveling direction of a laser beam are embedded with a fifth semiconductor layer.

Abstract: In a semiconductor laser device of the type which includes at least one laminate of a first dielectric layer and a second dielectric layer on at least one of the two facets of a resonator and in which the refractive index of the first dielectric layer is lower than that of the second dielectric layer, the improvement wherein the second dielectric layer consists of an amorphous material containing silicon and hydrogen at its essential constituent elements.

Abstract: This specification discloses a self-aligned manufacturing method of a Schottky gate FET. This method comprises the steps: forming a gate metallic layer on a semiconductor substrate and a mask overhanged on the metallic layer; ion-implanting impurity ions into the semiconductor substrate using the mask to form a source/drain region; depositing an insulator on the gate metallic layer side surface and the other surface below the mask; directionally etching said deposited insulator using the mask to expose the source/drain region; depositing a source/drain electrode using the mask; and removing the mask.

Abstract: Herein disclosed is a field effect transistor fabricating method comprising: the step of forming a surface portion of a semiconductor substrate with an impurity region for a channel; the step of forming a first material layer, which has a width substantially equal to that of a gate electrode, in such a position on said semiconductor substrate and is to be formed with said gate electrode, a second material layer, which has a width larger than that of said first material layer, above said first material layer, and source and drain regions by an ion implantation using said first and second material layers thus formed as a mask; the step of forming source and drain electrodes in contact with said source and drain regions; the step of forming a third material layer, which has a selectivity with said first material layer in its etched characteristics, on the semiconductor body thus far prepared by the foregoing steps; the step of forming at least an aperture by removing said first material layer in a state using sa

Abstract: Disclosed is a semiconductor laser device comprising a semiconductor assembly which serves to effect laser oscillation and in which first, second and third semiconductor layers are successively stacked on a predetermined semiconductor body, at least the first and third semiconductor layers being small in the refractive index relative to the second semiconductor layer and great in the forbidden band gap relative thereto and having conductivity types opposite to each other, and means to spread depletion regions within at least a part of a current path for effecting the laser oscillation and in a manner to intersect with the current path. A small-sized semiconductor laser device capable of fast modulation can be realized.

Abstract: A buried-heterostructure semiconductor laser including a mesa-shaped optical confinement region having an active layer and a clad layer and disposed on a semiconductor substrate; a burying layer burying both side surfaces of the region; and at least one p-n junction so formed inside the burying layer in parallel to the active layer as to be brought under the reversely biased state during the operation of the laser; wherein surface protection semiconductor layers are formed on the mesa-shaped optical confinement region and on the burying layer, respectively, for protecting the semiconductor assembly in the arrangement such that these surface protection semiconductor layers do not come into direct contact with each other.

Abstract: A semiconductor laser device of this invention has a built-in passive guiding mechanism along the junction plane by growing planar double hetero (DH) layers on a grooved or projected substrate. It operates stably in the lowest transverse mode and provides light-output versus current characteristics free of either kinks or any anomalies.

Abstract: Disclosed is a semiconductor laser device comprising a layered semiconductor region capable of laser oscillation and including at least an optical confinement region consisting of stacked semiconductor layers, means for injecting current into the optical confinement region, and means for constructing an optical resonator; switching means for supplying the layered semiconductor region capable of laser oscillation with a current having a value near a threshold current value for the laser oscillation; and switching means for feeding a current to be superposed on the current supplied to the layered semiconductor region capable of laser oscillation, this switching means being capable of controlling the current to be superposed through an external input thereof.

Abstract: Disclosed herein is a semiconductor laser device including at least an active region consisting of a semiconductor material and a semiconductor region consisting of a material having a different composition from that of the active region and confining the active region, wherein at least one p-n junction is formed inside the confining region in parallel to the active region and a current flowing through the active region at a field strength below an electric field causing degradation of the semiconductor laser device is allowed to flow through regions other than the active region via the p-n junction by controlling the impurity concentration of the region having the p-n junction. The semiconductor laser device does not undergo catastrophic degradation even when applied with a current higher than a rated value.

Abstract: A semiconductor laser light emitting element comprises a semiconductor substrate, a laminate region of semiconductor layers having at least a first, a second and a third semiconductor layer formed over the substrate and having a p-n junction defined therein. The first and third semiconductor layers have smaller refractive indices and greater forbidden band gaps than the second semiconductor layer and are opposite in conductivity type to each other. Provided are on the substrate a field effect transistor section having first and second electrodes and a gate electrode disposed between the first and second electrodes, a means for serving as an optical resonator for emitting light in the lengthwise direction of the p-n junction.

Abstract: A semiconductor laser element is disclosed which includes a film of an amorphous material deposited on at least an optical output facet of the laser element and contains silicon and hydrogen as the indispensable components. The thickness of the amorphous film is preferably selected in the vicinity of (.lambda./4).multidot.m where .lambda. represents wavelength of laser light in the amorphous film and m represents an odd integer. A film of a transparent insulation material can be deposited over the amorphous film thereby to constitute a composite film. With the disclosed structure of the semiconductor laser element, increasement in a threshold current of the laser element can be suppressed to a minimum, while a maximum optical output power can be increased.