Abstract: A method and system for screening international phone calls to reduce the number of phone calls which are made simply for the purpose of talking with international operators (prank phone calls) and to reduce the workload of the operators. When an international incoming phone call is placed from a calling terminal abroad, a database is used to determine, based on the calling country code of the incoming phone call, whether the call is from a prank phone call country. If the call is from a prank phone call country, an announcement for determining the intention of the caller is sent to the caller. If the caller provides a response to the announcement, a determination is made as to whether the response is valid. If the response is determined to be valid, the call is connected to the operator. If the response is invalid, the call is determined to be a prank call and is thus disconnected.

Abstract: An optical functional semiconductor element which performs ultrafast, high-contrast logic operation through utilization of the high speed of light velocity. A resonant-tunneling diode having a negative resistance characteristic is provided apart from a light absorbing layer formed by one of i-type layers of what is called a triangular barrier diode of an nipin or pinip structure, by which as the quantity of incident light increases, the quantity of transmitted current is switched from increase to decrease, the amount of change is made high-contrast and an ultrafast logic operation can be performed.

Abstract: Picture coded data that are obtained by coding at a coding rate R1 that is input via a coded data input terminal 1 are supplied to a variable length decoder. The variable length decoder decodes data for which variable length coding has been performed, and DCT coding information is transmitted to an inverse quantizer. A quantization controller calculates a quantization step that is necessary for re-quantization, and controls a quantizer. The DCT coding information for which the inverse quantization has been performed by the inverse quantizer is recovered into a DCT coefficient. The DCT coefficient is quantized again by a quantizer at quantization step Q that is determined by the quantization controller, and the result is transmitted to a variable length coder. The variable length coder performs variable length coding of the received data at a coding rate R2, and outputs the resultant picture coded data to a coded data output terminal.

Abstract: An optical transmission system which permits long-distance, ultrafast, high-capacity optical soliton transmission by suppressing timing jitter with simple means. In an optical transmission system which uses a transmission line composed of an optical fiber for transmitting therethrough a lightwave signal having digital information added to a return-to-zero lightwave pulse and a plurality of optical amplifying repeaters for compensating for losses by the optical fiber and in which the pulse compression effect by the nonlinear optical effect on the optical pulse and the pulse expansion effect by the dispersion effect are compensated, at least one optical band limited element which has a flat group delay characteristic near the center frequency is disposed in the transmission line at intervals of a period Z equal to the soliton period Z.sub.sol and the product, aB.sub.sol.spsb.

Abstract: A mobile communication system is disclosed which precludes the necessity for mobile station to perform processing for microcell zone switching even when it moves from one microcell zone to another and which permits high-speed microcell zone handover. The service area of mobile communication is split into a plurality of macrocells; the macrocells are each subdivided into a plurality of microcells; a microcell base station equipped with a transmitting and receiving antenna and a power amplifier is installed in each microcell; a different communication channel is assigned to individual mobile station in the macrocell; even when the mobile station moves from one microcell to another, no channel handover takes place; and only when the mobile station moves from one macrocell to another, a mobile network control center which supervises the macrocell base stations effects channel handover.

Abstract: An optical amplifying-repeating transmission system is disclosed which is composed of an optical fiber for transmitting a lightwave signal with digital information added to return-to-zero lightwave pulses and a plurality of optical amplifying repeaters inserted in the optical fiber for transmission use. The mean value of wavelengths at which the wavelength dispersion of the optical fiber is zero is smaller than the wavelength of the lightwave signal which is transmitted over the system. The accumulated wavelength dispersion value of the optical fiber tends to increase with the distance of transmission, from a macroscopic viewpoint. The optical fiber for transmission is divided into a plurality of sections.

Abstract: An optical transmitter which reverses the ON-OFF state of the optical intensity of a bright soliton lightwave and generates a dark soliton lightwave having an optical phase shift, an optical receiver for the dark soliton lightwave, and a superfast, high-capacity optical transmission system which is capable of increasing the soliton pulse array density while suppressing timing jitter. The optical transmission system is provided with the optical transmitter which transmits a dark soliton lightwave having digital information, the optical receiver which receives the dark soliton lightwave as a return-to-zero pulse and a transmission optical fiber interconnecting the transmitter and the receiver.

Abstract: An elliptic beam antenna easy to design and simple in structure. To generate elliptic beams of about the same size regardless of the kind of polarized waves for excitation, a horn antenna or waveguide structure intended for radiating out radio waves into space features the provision of diamond aperture, modified from the conventional circular, elliptical, square or rectangular one and excitation of radio waves in diagonal directions.

Abstract: In picture decoding from compressed data, noise component is predicted for each pixel, and noise-free original picture data is predicted from the predicted noise component and the decoded picture data, thus permitting picture quality improvement to be obtained.Horizontal and vertical picture noise reduction circuits are provided such that they are the same in the process contents and are different in the direction of data processing. An activity calculation circuit derives the activity of block-based decoded picture data, and a block mean noise prediction circuit predicts block mean noise according to the activity obtained in the activity calculation circuit. A pixel noise prediction circuit derives predicted noise in each pixel from the predicted block mean noise obtained in the block mean noise prediction circuit and the activity obtained in the activity calculation circuit. A filter coefficient determining circuit determines filter coefficients.

Abstract: The present invention provides a wavelength division multiplexed optical fiber transmission equipment which can increase the number of channels of the WDM signal by reducing a required bandwidth of optical signals while suppressing an interference between signals caused by four-wave mixing. A WDM optical transmitting terminal comprises five or more optical transmitters and the wavelengths of optical signals from the optical transmitters are set such that the spacing between the wavelengths of two signals is re-used as the spacing between the wavelengths of other two signals separated by the above signals by two or more waves and there is no periodicity in the channel spacing s. For instance, the wavelengths of the optical signals are set as shown in FIG. 1. As the result, deterioration in the transmission characteristics of the optical signals can be effectively reduced and, at the same time, the maximum number of channels of the WDM signal can be increased.

Abstract: An apparatus for measuring optical transmission characteristic, which has an input unit of data signal and of clock pulses, a signal decision unit, a display unit and a control unit. The signal decision unit comprises a plurality of signal decision circuits. A Q value employed as a parameter for the evaluation of the transmission characteristic of an optical communication system can be obtained in real time since bit error rates necessary for the calculation of the Q value can be simultaneously obtained by the plurality of signal decision circuits.

Abstract: The international direct dialing booking system of the present invention enables the circuit between a calling party and the other party to be connected by calling the other party on behalf of the calling party and calling back the calling party if the circuit with the other party is not connected in an international direct dialing for the reason that the circuit is busy, or the other party is talking with another person on the telephone or makes no response. In addition, the international direct dialing booking system enables the booking of an international telephone call by the use of an international direct dialing.

Abstract: A moving picture encoder which is able to improve the encoding efficiency wherein a controller controls an inter/intra mode switch for generating intra and inter signals Y2 and Y4, these signals being stored in a memory. A combining unit generates a combination pattern from the intra and inter signals Y2 and Y4 stored in the memory. An information amount estimator estimates the information amounts concerning the signals Y2 and Y4 and combination pattern. A minimum information amount determining unit determines the minimum one of the estimated information amounts. The controller causes a selector to select the signal or combination pattern that corresponds to the minimum information amount for quantizing and transmitting the result to a succeeding stage.

Abstract: An optical amplifying transmission system is disclosed in which a large quantity of optical fiber whose zero dispersion wavelength is longer than the wavelength of the lightwave signal is introduced to provide an RZ lightwave signal transmission system. In this system, the average zero dispersion wavelength by the optical fiber is shorter than the wavelength of the lightwave signal, the zero dispersion wavelength by the optical fiber whose length is in the range of one-thirds to two-thirds of the entire length of the optical fiber is longer than the wavelength of the lightwave signal, and the absolute value of the wavelength dispersion is larger than one-half the absolute value of the average wavelength dispersion value over the entire length of the optical fiber.

Abstract: A sync controller 14 controls an amount of delay of a delay part 15 so that original video data entered from a video source 1 is synchronized with reproduced video data which is compressed and reproduced by a system to be evaluated. A first OT calculator 17 orthogonally transforms a reproduced image, a second OT calculator 21 orthogonally transforms an original image and a subtractor 19 obtains a difference value of the same order coefficients in one block. A WSNR calculator 22 weights the difference with a weighting function which varies with a position of a coefficient of orthogonally transformed data and a magnitude of an AC power in the block after orthogonal transform of the original image and subsequently obtains an average weighted S/N ratio of each video frame or a plurality of video frames. Finally, a subjective evaluation value calculator 23 calculates a subjective evaluation value (deterioration percentage) according to the average weighted S/N ratio.

Abstract: An accurate motion vector is locally estimated in a moving image, and motion compensation is performed on the image in the immediately preceding frame based on the motion vector obtained. Next, a low pass filter is applied between the current frame and the immediately preceding frame that has been motion compensated. By controlling the filter coefficient in pixel units when the filter is applied, blurring of a moving image is suppressed to a minimum while noise is largely reduced.

Abstract: It is the object of the present invention to optimize the degradation due to the four-wave mixing of wavelength multiplexed signals and the distortion due to the chromatic dispersion, thereby to provide a wavelength division multiplexed optical fiber transmission equipment having good transmission characteristics. A WDM transmitting terminal consists of four transmitters of channels 1 to 4, and a wavelength-division multiplexer. Further, a WDM receiving terminal consists of an equalization optical fiber, a wavelength-division demultiplexer, and four receivers of the channels 1 to 4. The WDM transmitting terminal and the WDM receiving terminal are interconnected by transmission optical fibers and an optical amplifier. The equipment is designed so that the wavelengths .lambda..sub.1, .lambda..sub.2, .lambda..sub.3 and .lambda..sub.4 of the optical signals output from the transmitters all lie on the short-wavelength side with respect to the average zero-dispersion wavelength .lambda..sub.0.

Abstract: A quantizer designed by using human visual sensitivity is disclosed, in which when postprocessing is done after inverse quantization an optimum visual sensitivity function for a system involving the postprocessing is obtained for doing quantization by using that visual sensitivity function.Where the postprocessing that is executed after the inverse quantization consists of a filtering process with a characteristic L(.omega.) (.omega. being the frequency) and a 1:2 interpolation process, denoting the optimum visual sensitivity as the output result by W(.omega.) as shown in FIG. 2, the optimum equivalent sensitivity function W'(.omega.) is given asW'(.omega.)=1/2[L(.omega./2)W(.omega./2)+L(.omega./2+.pi.)W(.omega./2+.pi.) ].By using this equivalent sensitivity function W'(.omega.) for the quantizer, it is possible to obtain a visually optimum quantizer designed by using human visual sensitivity.

Abstract: In the present invention, by performing a control so that the I-coding modes of the encoders of a plurality of respective channels do not overlap each other, the amount of generated encoded information for the total system can be reduced without reducing the allowed amount of information of each encoder. Further, the bit rate Ri (i=1, 2, 3, . . . ) which minimizes the mean square error (E) is determined, on condition that the total bit rate (R) is constant, and informed the encoder. The encoder encodes a video signal at the specified bit rate. This allows the total performance of the plurality of encoders to be increased under a predetermined total bit rate.

Abstract: A system for determining and registering the location of mobile terminals in a mobile communication system using non-geosynchrous satellites, in which each land earth station transmits its identification information via spot beams of satellites or together with identification information of a spot beam and that of satellite. A mobile terminal thus receives identification information, and transmits the received identification information together with information on time of reception and the terminal identifying information to the terrestrial network for registering the latest location information. Since the latest location information of mobile terminal is registered in the terrestrial network as mentioned above, a call can be connected to the mobile terminal simply by sending a call announcement message by referring the registered location information. This leads to reduction of the number of circuits that are needed for sending call announcement messages.