Abstract: A dispersion compensation device and an optical transmission system are capable of simultaneously compensating a dispersion value and dispersion slope in a single-mode optical fiber in a high-speed long-distance optical transmission system and a wavelength division optical transmission system. The dispersion compensation device includes N number of component optical fibers arranged in a serial fashion, N being a positive integer more than one, wherein each of the component optical fiber has a different dispersion value per a unit length, a dispersion slope per a unit length, and a different length.

Abstract: A power on/off control device having a first power supply outputs a predetermined first electric power upon receiving input power and a second power supply outputs a main electric power to operate the computer upon power-on, which is turned on and off according to power driving signals of a first level or a second level. A power switch outputs a first level while the power switch is being pressed down, and a second level while not pressed down. A power driving signal output outputs power driving signals of the first level or of the second level alternatively according to inputted pulse signals from a microprocessor, the microprocessor has a first port connected with the power switch and a second port coupled with the power driving signal output, for controlling power on/off according to signal levels from the first port and the second port. A data output forwards data outputted from the microprocessor to a system data bus. A data input sends data inputted through the system data bus to the microprocessor.

Abstract: A duplex board system comprises two functionally identical processing boards, one of the boards being in an active state and the other being in a stand-by state, each of the boards generating a state signal depicting the state thereof, wherein the stand-by state board succeeds the active state board when the state of the active state board becomes deactivated; and two cancelling units, each coupled between the two boards for receiving the state signal from one of the boards, suppressing a glitch period from the state signal generated at said one of the boards, the glitch period representing an unstable signal level transition of the state signal, and outputting the glitch suppressed state signal to the other board.

Abstract: A program selection driving device for a personal computer is provided, through which a user can executes a desirous program simply by operating a specified button, comprising a button panel 712 having a plurality of selecting buttons on an outside of a main computer 71 and a remote signal receiver 711 for inputting a specified remote control signal. A CPU 20 executes a corresponding program the user wants when a specified selecting signal is inputted from the button panel 712 and the remote signal receiver 711. And a hard disk of the computer includes a first memory region storing a program for the program selection driving and a second memory region storing directory information and execution file names related to selectable programs registered. A program can be registered in the second memory region, in execution of a program stored at the first memory region, by a drag and drop function.

Abstract: An apparatus for monitoring selected one of multiple channels comprises a counting unit for increasing a count value when an up mode is selected and for decreasing the count value when a down mode is selected, wherein the count value corresponds to a channel number of the multiple channels; a mode selecting unit for selecting one of the up and the down modes; a unit for inputting a channel number; a unit for generating a count value corresponding to the channel number from the inputting unit and a write-enable signal; a source selecting unit for selecting one of the count values from the counting unit and from the generating unit; a signal generating unit for generating a channel selecting signal corresponding to the count value; a converting unit for extracting data from a channel depicted by the channel selecting signal and converting transmission rate of the data; and an analyzing unit for monitoring the data from the converting unit to check whether or not the data is transferred properly.

Abstract: A method effectively stores data onto each of buffers included in a storage device of a processor, wherein the data is data being communicated between the processor and each of devices coupled thereto. It is first checked whether or not a flag is set to a target buffer among the buffers. If not, it is further checked whether or not a length of the data to be stored is larger than a predetermined length based on head information of the data. The data and the head information are stored onto the target buffer if the data length is not larger than the predetermined length and a flag is set to the target buffer. But, if the data length is larger than the predetermined length, the data is processed to store it onto two or more buffers.

Abstract: A method generates an authentication key to be used in an authentication algorithm at position at which a mobile station's subscriber is located. First, when there is a request to create the authentication key by a customer service center (CSC), at an authentication center module (ACM), a first type of parameters are issued and transmitted to a mobile station (MS). At the MS, a reference key to be used in creating the authentication key is then obtained on the basis of the first type of parameters to send the reference key to the ACM. A second type of parameter is derived by using the first type of parameters when the reference key is received from the MS and then transmitted to the MS at the ACM. At the MS, the authentication key is generated by using the first type of parameters, the second type of parameter and the reference key and a key generation complete message is transferred to the ACM.

Abstract: A bidirectional optical fiber amplifier includes a first and a second transmitters for generating a first and a second signal lights, respectively, a first and a second receivers for receiving the first and the second signal lights, respectively, a fiber amplifier for amplifying the first and the second signal lights, a first optical circulator for transmitting the first signal light from the first transmitter to the fiber amplifier and for transmitting the second signal light from the fiber amplifier to the second receiver, a second optical circulator for transmitting the first signal light from the fiber amplifier to the first receiver and for transmitting the second signal light from the second transmitter to the fiber amplifier and a pair of optical pumps for pumping the fiber amplifier.

Abstract: A terminal assembly for an optic cable equipped with terminal connectors is provided with a housing having a small through-hole and a large through-hole. A plug for keeping optical fibers within the housing to prevent the optical fibers from getting entangled with one another is mounted within the housing. Through the use of a nut member fixed to the cable, the housing is fixed to the cable. A flexible cap member for enclosing the optical fibers and the terminal connectors is combined with the housing to enclose them.

Abstract: A constant envelope quadrature amplitude modulation system is provided for solving the bandwidth efficiency problem resulting from a lack of frequency resources by implementing the constant envelope characteristic for a non-linear communication system, based on a 16-QAM (Quadrature Amplitude Modulation) system. The system limits the data, which will be modulated and transmitted, to 3-bit data and adds a parity bit to make the data have a constant envelope within the 16-QAM system, which modulates data to be transmitted in the unit of 4-bit. The data value of the parity bit is selected to satisfy the condition of a constant envelope in accordance with the QAM signals.

Abstract: The present invention relates to an apparatus for tilting a keyboard of portable computer, in a manner that a rear end of the keyboard is raised up to a predetermined height by opening its cover, so that the user can operate keys of the keyboard more conveniently. The apparatus for tilting the keyboard of a portable computer of the invention can radiate heat generated from various electric components on a main PCB of a base, during operating the computer, through a ventilation space formed between a keyboard cage on the top side of the base and a bottom side of the keyboard when opening the cover. The apparatus in accordance with the present invention comprises: a keyboard of which both sides of a front portion are rotatably joined by hinge means to a front portion of a keyboard cage formed on a base. A cover is rotably engaged with the base by hinge means mounted within an interior of a rear side portion of the base to be engaged with at least a protruding member of the cover.

Abstract: An optical amplifier for amplifying signal lights propagating in two opposite directions comprises a 1st and a 2nd transmitters for generating a 1st and a 2nd signal lights, respectively, a 1st and a 2nd receivers for receiving the 1st and the 2nd signal lights, respectively, a fiber amplifier for amplifying the signal lights, a 1st optical device including a 1st and a 2nd wavelength division multiplexing(WDM) couplers, a 1st and a 2nd isolators, a 2nd optical device including a 3rd and a 4th WDM couplers, a 3rd and a 4th isolators and a pair of light sources for pumping the fiber amplifier. In the optical amplifier, the 1st WDM coupler selectively transmits the 1st signal light from the 1st transmitter to the fiber amplifier via the 1st isolator and the 2nd WDM coupler, and the 2nd WDM coupler selectively transmits the 2nd signal light from the 2nd transmitter to the 2nd receiver via the 2nd isolator and the 1st WDM coupler.

Abstract: A data processing system having a CPU (central processing unit), a system bus and a main memory connected to the system bus, comprises a cache memory connected to the system bus for storing a predetermined part of data stored at the main memory, a first path unit for coupling the CPU with the cache memory, a second path unit for connecting the CPU to the system bus, and controller for enabling one of the first and the second path units. In the data processing system, the main memory is accessed only if a cache miss occurs while the first path unit is enabled, and the main memory and the cache memory are accessed simultaneously while the second path unit is enabled.

Abstract: A feedback-type optical fiber amplifier using hybrid pumping light beams disclosed, including: an optical line through which an optical signal is propagated; a plurality of rare-earth-doped fibers, doped with a predetermined rare earth ion, being coupled to the optical line in series; a plurality of pumping light sources for outputting pumping light beams having wavelengths different from each other; a plurality of optical coupling means for coupling the pumping light beams to the optical line; and feedback means for dividing the pumping light beam outputted through at least one of the rare-earth-doped fibers, and looping it back to corresponding rare-earth-doped fiber as its input. Therefore, the length of fiber constructing the optical fiber amplifier is reduced, and the amplification efficiency is improved.

Abstract: A bus architecture for use in a data communication system provides a communication path between processors and one or more external devices including (M+1) hierarchical processors. Each of the processors is categorized into one of N hierarchies with M and N being a positive integer larger than 1, respectively, and N is smaller than (M+1). The bus architecture includes a bus having N buses, each of the buses coupled to one or more processors of a hierarchy and (N-1) linking means, and each of the linking means for coupling a bus of a hierarchy to a bus of a next hierarchy.