Abstract: A semiconductor optical modulator having an electroabsorptive layer and a pair of modulating voltage electrodes also has a direct-current voltage electrode, from which an unmodulated electric field can be applied to the electroabsorptive layer to adjust the output optical power level. The output optical power level can thus be adjusted without the need for an external attenuator, and without shifting the modulating voltage away from the part of the extinction ratio characteristic having the best linearity. An optical multiplexing module using semiconductor optical modulators of this type can generate a multiplexed output signal with a uniform optical power level simply by controlling the direct-current voltages applied to the semiconductor optical modulators.

Abstract: In a clock switching circuit, a write address is generated based on a pre-switched clock, and the write address is employed to store input data in memory. Then, a read address is generated based on a post-switched clock, and the read address is employed to read data from memory, so that a clock synchronized with the data is changed. There are multiple pre-switched frequencies, and the frequency of a post-switched clock is higher than the frequency of a pre-switched clock. When the pre-switched clock frequency is lower than the post-switched clock frequency, the read address is updated in accordance with a ratio of the frequency of the pre-switched clock to the frequency of the post-switched clock.

Abstract: A semiconductor device has a drift region in which a drift current flows if it is in the ON mode and which is depleted if it is in the OFF mode. The drift region is formed as a structure having a plurality of first conductive type divided drift regions and a plurality of second conductive type compartment regions in which each of the compartment regions is positioned among the adjacent drift regions in parallel to make p-n junctions, respectively.

Abstract: In an aerostatic gas bearing, slot sections can be easily processed, bearing stiffness and a load capacity can be improved, and an amount of gas flow can be greatly reduced as compared with a conventional circular slot restriction bearing. A multiplicity of radial slots are formed on both the end surfaces of a bearing member. A bearing housing is assembled by fixing slot side plates on both the side surfaces thereof and accommodated in a casing, and a shaft having an outside diameter slightly smaller than the inside diameter of the bearing housing is inserted through the bearing housing. Gas is fed from a gas feed port and flown into a multiplicity of slots through a peripheral groove and fed-gas introduction path. The gas flows into the radial bearing clearance between the shaft and the inner peripheral surface of the bearing housing, thereby the shaft is rotatably supported.

Abstract: In a system in which a plurality of programs each enter an execution wait state at a given time point and they are sequentially executed in the order of their cutoff times, the execution completion time point of a program undergoing estimation of execution completion thereof is estimated based upon the average value of intervals representing the lengths of time to elapse before an execution request for a program present in the system arrives, the average value of the execution times of the individual programs in the system, the lengths of time to elapse between the execution request arrival time points and the cutoff times, the execution time of the program undergoing estimation of execution completion thereof and the execution request arrival time point of the program undergoing estimation of the execution completion thereof, thus achieving a structure that enables estimation of the response time of a program without necessitating a lengthy process such as an actual or simulated execution of the program.

Abstract: A picture coder divides a frame of coded picture data into a critical segment including information needed for decoding other segments in the frame, and at least one non-critical segment including only information needed for its own decoding. The critical segment is made smaller than the non-critical segments, by controlling the segment size directly, for example, or by controlling a quantization step size or a forced intra-coding rate. The small size reduces the probability of the loss of critical information during packet transmission of the coded data, when each segment is transmitted as a separate packet. Alternatively, the size of all segments is reduced when conditions on the communication path indicate a high probability of transmission errors.

Abstract: It is an object of the present invention to provide an optical filter which allows parameters to be easily adjusted, which allows birefringence and temperature dependence to be easily compensated for, and which is essentially free from dispersion. The optical filter includes an optical coupler that splits light into two beams, optical couplers connected to outputs of the optical coupler, a first group of two optical waveguide delay lines connected to the coupler, a second group of two optical waveguide delay lines connected to the coupler, an optical coupler that combines lights from the first group of the lines, an optical coupler that combines lights from the second group of the lines, and a multimode interference optical coupler that combines lights from the couplers together.

Abstract: A semiconductor device has a drift region in which a drift current flows if it is in the ON mode and which is depleted if it is in the OFF mode. The drift region is formed as a structure having a plurality of first conductive type divided drift regions and a plurality of second conductive type compartment regions in which each of the compartment regions is positioned among the adjacent drift regions in parallel to make p-n junctions, respectively.

Abstract: There is provided an optical fiber to be coupled to a laser diode light source. The optical fiber has a wedge-shaped lens for decreasing the influence of reflection light BR1 and returning reflection light BR2, whereby the laser diode light source can be operated with stability. The wedged and lensed optical fiber according to the present invention is arranged such that the optical fiber is formed to have a wedge-shaped lens at the tip end thereof, a ridge as a rooftop is made to include the center tip end of a core, the ridge is inclined by an inclination angle &bgr; with respect to a plane perpendicular to the optical axis of the optical fiber, and the ridge is formed into a semi-cylindrical surface or a conical surface.

Abstract: A positioning mark of a soft magnetic film is provided at the center of a master disk, and a beam from a light source irradiates the position of the mark. When a optical reception sensor using a CCD recognizes the mark, the recognizability of the positioning mark can be improved by using a wavelength selective filter or a laser as the light source. Additionally, the recognizability of the positioning mark can be improved by forming the positioning mark using a material other than a soft magnetic material.

Abstract: A semiconductor device has a drift region in which a drift current flows if it is in the ON mode and which is depleted if it is in the OFF mode. The drift region is formed as a structure having a plurality of first conductive type divided drift regions and a plurality of second conductive type compartment regions in which each of the compartment regions is positioned among the adjacent drift regions in parallel to make p-n junctions, respectively.

Abstract: A hub apparatus which has a plurality of ports for connecting a network portion including one or a plurality of communicating apparatuses and relays the transmission and reception of a communication packet between the communicating apparatuses through the ports. The hub apparatus has port information storing means for storing, every said port, port information regarding the network portion which includes at least information indicating whether the number of communicating apparatuses which the network portion connected to each port has is equal to 1 or a plural number, and means for determining communicating forms of transmission, non-transmission, and a state of the communication packet for transmitting on the basis of the port information corresponding to the port to which the communication packet is sent.

Abstract: An eccentric optical fiber connector ferrule according to the present invention comprises an optical fiber in which a coating at an end thereof is removed to expose the end of the fiber, a metallic coating bonded to a part of a side face at the end of the optical fiber in an axial direction, and a ferrule receiving the end of the optical fiber, to which the metallic coating is bonded, in a central hole, for supporting it while applying a specified eccentricity. By recessing the optical fiber end face of the eccentric optical fiber connector ferrule from the ferrule end face by 0.2 to 2.0 &mgr;m, the damage at the end of the optical fiber can be prevented.

Abstract: An optical device includes a transparent material layer having a desired curved surface configuration, a layer including a variable refractive index material having a dielectric constant anisotropy, at least two transparent electrodes arranged to sandwich the transparent material layer and the variable refractive index material, and a driving device supplying a voltage including driving frequencies f1 and f2 between the transparent electrodes. The difference &Dgr;∈ in the dielectric constant of the variable refractive index material due to the anisotropy is positive at one of the driving frequencies and negative at the other driving frequency.

Abstract: A bit position synchronizer including a sampling circuit which samples an input signal based on a plurality of phases of clock signals to obtain a plurality of sampled signals, a selector which selects one of the plurality of sampled signals, each of which is delayed for a short period, based on a selection signal and which outputs an output signal, a detection circuit which detects a first changing point and a second changing point of the sampled signals, a first register which stores a first value for the first changing point, a second register which stores a second value for the second changing point and a third register which stores an intermediate value between the first and second values and which outputs the selection signal.

Abstract: A transcoder converts data between a telephony data format and a packet data format. The transcoder comprises: a digital logic telephony data engine receiving telephony data for the transcoder and transmitting telephony data for the transcoder, the digital logic telephony data engine comprising a frame accumulation buffer; a digital logic packet engine receiving packet data for the transcoder and transmitting packet data for the transcoder; a digital signal processing complex coupled to the digital logic telephony data engine and the digital logic packet engine, the digital signal processing complex comprising an array of digital signal processors; and a host processor coupled to the digital logic telephony data engine and the digital logic packet engine, wherein the digital logic telephony data engine, the digital logic packet engine, and the digital signal processing complex perform media channel processing, wherein the host processor performs control channel processing.

Abstract: A wireless transmitter transmits data with at least two different levels of required quality on the same wireless channel. The transmitter has a multiplexer that multiplexes the data into frames, each frame containing data with at least two different levels of required quality, and a power controller that controls the transmitting power of each type of data separately within each frame, thereby avoiding the use of excess transmitting power.

Abstract: A semiconductor device has a drift region in which a drift current flows if it is in the ON mode and which is depleted if it is in the OFF mode. The drift region is formed as a structure having a plurality of first conductive type divided drift regions and a plurality of second conductive type compartment regions in which each of the compartment regions is positioned among the adjacent drift regions in parallel to make p-n junctions, respectively.

Abstract: According to the present invention, if an EMS110 needs to conduct control over a prescribed group of nodes 120 in the IP network 140 to exert a predetermined function, that is, to change the control mode, it creates, according to a control program, an active program AP which stores a control-subject address table and control contents of that group and then transfers it through a control network 150. At each node 120, if the active program executed by itself has normally ended, records this normal ending in the control-subject address table of the active program AP and also, based on this control-subject address table, transmits the active program to such a node 120 in the control-subject group that has not executed that program yet. If the active program AP has abended, on the other hand, it records this abending in the control-subject address table of the active program AP and also transmits the active program AP to the EMS110, thus suspending the control processing.