Abstract: A semiconductor device according to the invention of the present application comprises a first semiconductor layer, a first insulating layer formed over the first semiconductor layer, a second semiconductor layer formed over the insulating layer, a protective element formed over the second semiconductor layer, an electrode pad, and a plurality of series-connected through holes for connecting the electrode pad and the protective element. Thus, a surge voltage applied across a diffused resistor can be lightened and hence an oxide film placed below the diffused resistor can be prevented from destruction.

Abstract: The invention has been developed to find out a blemish on the surface of a disk (in particular, a stroke mark in the CSS area) without opening up a hard disk. Furthermore, the invention is intended not to cause extra labor or cost in fabrication of hard disks, and to be applicable to hard disk already in widespread use. To this end, with an acoustic inspection method of the invention, inspection of whether or not a blemish has been inflicted on the surface of a disk (in particular, a blemish in the CSS area) can be conducted without opening up the hard disk by detecting vibration occurring when a head of the hard drive comes into collision with the blemish on the disk from vibration propagating to a housing of the hard disk.

Abstract: A ferroelectric memory device in which an imprint is prevented, and a method of operating the ferroelectric memory device to prevent its characteristics from deteriorating due to an imprint. The ferroelectric memory device includes a sense amplifier having first and second transistors which connect first and third sub-bit lines to a ground in accordance with a sense amplifier control signal, third and fourth transistors which connect the first sub-bit line with a fourth sub-bit line and further connect the third sub-bit line with a second sub-bit line in accordance with a first switching control signal, and fifth and sixth transistors which connect the first sub-bit line with the second sub-bit line and further connect the third sub-bit line with the fourth sub-bit line in accordance with a second switching control signal.

Abstract: An input protection circuit capable of precisely bypassing a surge current to a power source terminal and protecting the gate of a protective transistor from an electrostatic surge. The input protection circuit has an input terminal which receives an input signal, a first power source terminal which receives a first power source electric potential, and a first protective power source potential line connected to the first power source terminal for supplying the first power source electric potential to an input protection circuit. The input protection circuit has a first input protection transistor of a first conductive type having a drain connected to the input terminal, a gate and a source connected to the first protective power source potential line.

Abstract: A tuning circuit includes an oscillator that receives an oscillating input signal and a control signal, and generates an oscillating output signal. The control signal is obtained from a frequency control circuit that compares the phases of the oscillating output signal and a reference signal. The control signal controls the transconductance of a transconductance element in the oscillator, thereby controlling the oscillator output frequency. The oscillating input signal is obtained from an amplitude control circuit that detects an amplitude limit of the oscillator output. The oscillator output amplitude is responsive to the oscillating input signal. Frequency control and amplitude control in this tuning circuit are mutually independent, so their respective control loops remain stable under all frequency and amplitude combinations.

Abstract: The speech synthesis apparatus of the present invention includes: a text analyzer operable to generate a phonetic and prosodic symbol string from character information of an input text; a word dictionary storing a reading and an accent of a word; an voice segment dictionary storing a phoneme that is a basic unit of speech; a parameter generator operable to generate synthesizing parameters including at least a phoneme, a duration of the phoneme and a fundamental frequency for the phonetic and prosodic symbol string, the parameter generator including a calculating means operable to obtain a sum of phrase components and a sum of accent components and to calculate an average pitch from the sum of the phrase components and the sum of the accent components, and a determining means operable to determine a base pitch from the average pitch; and a waveform generator operable to generate a synthesized waveform by making waveform-overlapping referring to the synthesizing parameters generated by the parameter generator a

Abstract: An apparatus has a head portion for holding a strip of filter, and a support portion for supporting the head portion. The head portion has a guide portion for guiding the filter, a pair of plate members disposed on both sides of the guide portion, with a space left between tips of the plate members and with vicinities of the tips provided at a given angle, and a pair of blades disposed on the tips of the plate members. When the head portion is pressed against a V-shaped channel by the support portion, elastic deformation occurs in the pair of plate members, narrowing the space between the edges of the pair of blades. When the head portion is moved off the V-shaped channel, the space between the edges of the pair of blades expands to an original width.

Abstract: A ferroelectric memory of the present invention comprises a memory cell which includes a select transistor whose control electrode, first electrode and second electrode are respectively connected to a word line, a bit line and a first node, a ferroelectric capacitor whose first electrode and second electrode are respectively connected to the first node and connected to a plate line through a second node, and a resistor connected between the first node and the second node.

Abstract: An antenna duplexer has a first filter and a second filter coupled to respective signal terminals and to a common node. The common node is coupled to an antenna terminal. The first filter has a higher-frequency passband than the second filter. A transmission-line circuit, inserted between the first filter and the common node, increases the impedance of the first filter in its lower stopband. The transmission-line circuit includes an internal node, a first transmission line coupling the internal node to the common node, a second transmission line coupling the internal node to the first filter, and a grounding circuit such as a capacitor coupling the internal node to ground. The grounding circuit further enhances the lower stopband impedance of the first filter.

Abstract: This invention provides an improved optical amplifier, which comprises a rare earth doped optical fiber for amplifying the optical signal, at least one pump laser for providing a pump signal to the rare earth doped optical fiber, a wavelength division multiplexer for extracting a backward amplified spontaneous emission (ASE) signal in the C-band wavelength (1525-1565 nm) differ from the L-band wavelength (1565-1610 nm) containing the optical signal to be transmitted, a gain controller for controlling a power level of the pump signal based on a received power of the backward ASE signal.

Abstract: A digitized image is encoded by detecting edges in the image, encoding the position and sharpness of the detected edges, filtering the image by a low-pass filter to generate a low-frequency image, and encoding the low-frequency image. A digitized image encoded in this way is reconstructed by generating a horizontal edge image and a vertical edge image from the encoded edge position and sharpness information, synthesizing a pair of high-frequency images by filtering the horizontal and vertical edge images with an edge synthesis filter, decoding the low-frequency image, and performing an inverse wavelet transform on the decoded low-frequency image and the high-frequency images.

Abstract: A lightwave system comprises an optical signal bus; an input/output interface including a first, a second and a third port, an optical signal inputted to the first port being outputted from the second port, an optical signal inputted to the third port being outputted from the first port; an optical tap, through which the optical signal which is outputted from the second port of the input/output interface is sent to the optical signal bus; a variable wavelength filter, through which an optical signal having a designated wavelength is outputted from the optical signal bus, thereby being sent to the third port of the input/output interface; and a controller which designates the wavelength of the optical signal which is to be sent from the optical signal bus through the variable wavelength filter.

Abstract: An optical directional coupler includes a first waveguide, a second waveguide and a plurality of bridge waveguides connecting the first waveguide and the second waveguide.

Abstract: A method of fabricating an optical waveguide device has the steps of forming a Bragg grating by applying ultraviolet light to an optical waveguide to generate photoinduced refractive index changes, and adjusting characteristics of the Bragg grating by applying ultraviolet light for trimming to the optical waveguide. The Bragg grating forming step is executed by applying ultraviolet light to the optical waveguide through a phase mask, and the adjusting step is executed by applying ultraviolet light for trimming to the optical waveguide not through the phase mask.

Abstract: A spread-spectrum communication apparatus transmits and receives packets of data preceded by reference signals used in demodulating the packets of data. A control unit in the communication apparatus estimates channel conditions, and varies the length of the transmitted packets, hence the intervals between reference signals, using longer packets under better channel conditions. Configuration information indicating the packet length may also be transmitted. Excessive overhead can thus be avoided without impairing the accuracy of channel estimates used in demodulating the received data.

Abstract: Decoded image converting circuitry includes a display image compression circuit to which image data are input in the form of consecutive macroblocks. The compression circuit compresses each macroblock, a sequence of sixteen horizontal image data at a time, with a preselected compression ratio. The compressed image data representative of an I (Intra coded) picture and a P (Predictive coded) picture are written to a first memory while the compressed image data representative of a B (Bidirectionally predictive coded) picture are written to a second memory. The image data stored in the first and second memories each is read out at a preselected timing allowing raster scan data to be formed. A display image expansion circuit expands the compressed I and P pictures and B picture and thereby outputs raster scan data. An apparatus including the decoded image converting circuitry and a method practicable with the apparatus are also disclosed.

Abstract: An electromagnetic wave amplifier and an electromagnetic wave generator operate using electron beams in a vacuum environment. The amplifier, arranged in a vacuum environment, comprises an electron emitting section for emitting electron beams and an amplifying section for amplifying an inputted electromagnetic wave in one direction by utilizing energy received from an electron beam emitted from the electron emitting section and traveling in the vacuum along a dielectric waveguide having a wave-shaped form. The generator, also arranged in a vacuum environment, comprises an electron emitting section for emitting electron beams and an oscillating section for generating an electromagnetic wave by utilizing electron beams emitted from the electron emitting section and travelling in the vacuum along a dielectric waveguide having a composite wave-shaped form.

Abstract: A serial communication circuit sends or receives a large amount of data speedily. A buffer 2a is connected to a serial interface circuit 1a, and a buffer 2b is connected to a serial interface circuit 1b. One end of a switch 4 is connected to the serial interface circuit 1a or the serial interface circuit 1b, and another end to a serial port 3. Switching the switch 4 sequentially to the serial interface circuit 1a and to the serial interface circuit 1b makes it possible to use the two buffers for sending data to, or receiving data from, one serial port 3.

Abstract: In an optical transmission system, an optical output control device for an optical wavelength multiplexer includes a wavelength generation circuit for generating wavelength data representative of a wavelength &lgr;1 or &lgr;2 and implemented by a decimal number or a binary number. A wavelength administrative byte generation circuit receives the &lgr;1 or &lgr;2 wavelength data and transfers it to a wavelength administrative byte insertion circuit and a wavelength administrative byte detection circuit. The wavelength administrative byte insertion circuit inserts the &lgr;1 or &lgr;2 wavelength data in the positions of bytes D1 and D2 of a high-speed signal, transforms the resulting multiplex signal to a corresponding optical signal, and delivers the optical signal to an optical multiplexing circuit. The multiplexing circuit multiplexes high-speed optical signals respectively having the wavelengths &lgr;1 and &lgr;2 and feeds the resulting multiplex high-speed optical signal to an optical amplifier.

Abstract: An optical filter is manufactured by placing a photosensitive optical fiber in a spiral arrangement on a fiber holder, preferably having a spiral groove for holding the fiber, and exposing the fiber to ultraviolet light through a phase mask having a spiral diffraction grating, forming an in-fiber Bragg grating. The fiber can be conveniently scanned by an ultraviolet beam as the fiber holder and phase mask turn on a rotating stage. The fiber can be compactly packaged between the fiber holder and a cover. The fiber holder and cover can be formed by coating a substrate with layers of polymer material, the spiral groove being formed by photolithographic patterning of one of the layers.