Abstract: The capacitance of the capacitor with the constant capacitance is equivalently reduced in the capacitance of a resonant capacitor in a voltage control oscillator to increase the variable amount of the capacitance of the resonant capacitor, and to expand an oscillation frequency range. There are provided a differential negative conductance generator circuit having two resonation nodes for differential output, a differential resonant circuit having a variable capacitance that is controlled by voltage control and an inductance connected in parallel to each other, and a differential negative impedance circuit. A resonant circuit and a negative impedance circuit are connected between the resonation nodes. The capacitor with the constant capacitance that occurs between the resonation nodes is reduced by the negative impedance of the negative impedance circuit.

Abstract: There is provided not only a radio frequency power amplifier using an SiGe HBT subject to a little amplification distortion, but also a communication system using the same. A conventional radio frequency power amplifier provides base bias paths of transistors Q1 through QN (SiGe HBT) with bias resistors R11 through R1N having resistance values three to five times higher than those of a ballast resistor attached to each transistor's base. A coil LB is provided in parallel with the bias resistor as a means for compensating a voltage drop due to direct current component IDC flowing through the bias resistor. Addition of the bias resistor suppresses non-linearity of low-frequency variations in an output current. Addition of the coil compensates for voltage drop. Accordingly, the maximum linear output power can be improved. As a result, it is possible to provide the power amplifier subject to a little amplification distortion within a wide output range.

Abstract: The object of the invention is to provide a frequency generator which is composed of an oscillator and a frequency doubler and in which difference in amplitude between differential outputs of the frequency doubler can be equalized at low power consumption without adjustment. To achieve the object, the amplitude of differential outputs of the frequency doubler is detected and the delay time of a variable delay circuit is controlled. Owing to this configuration, in case a frequency of the oscillator varies or in case delay time by the delay circuit used in the frequency doubler varies by process variation and others even if the frequency is fixed, the amplitude of the differential outputs of the frequency doubler can be also equalized in the frequency generator.

Abstract: There are provided a variable inductor with little degradation in quality factor, and an oscillator and a communication system using the variable inductor. An inductance controller comprising a reactance device with a variable device value, such as, for example, a variable capacitor, is connected to a secondary inductor, magnetically coupled to a primary inductor through mutual inductance. The inductance controller is provided with an inductance control terminal for receiving a control signal for controlling capacitance of the variable capacitor. Inductance of the primary inductor is varied by varying the capacitance by the control signal.

Abstract: Semiconductor devices provided with high performance high-frequency circuits that reduce interference caused by inductors are provided. In the semiconductor device including a modulator circuit to modulate a carrier wave by a base band signal to output an RF signal and a demodulator circuit to demodulate the RF signal by use of the carrier wave to gain the base band signal and a local oscillator to generate the carrier wave, inductors respectively having a closed loop wire are adopted. Interference caused by mutual inductance is reduced by the closed loop wire. For example, where inductors are adopted in the modulator circuit, a closed loop wire is disposed around the outer periphery of the inductors.

Abstract: The object of the invention is to provide a frequency generator which is composed of an oscillator and a frequency doubler and in which difference in amplitude between differential outputs of the frequency doubler can be equalized at low power consumption without adjustment. To achieve the object, the amplitude of differential outputs of the frequency doubler is detected and the delay time of a variable delay circuit is controlled. Owing to this configuration, in case a frequency of the oscillator varies or in case delay time by the delay circuit used in the frequency doubler varies by process variation and others even if the frequency is fixed, the amplitude of the differential outputs of the frequency doubler can be also equalized in the frequency generator.

Abstract: A frequency generator which can perform stable frequency oscillation unaffected by temperature variation. A frequency generator having a differential amplifier (1) having an LC resonance circuit (10) as a load and buffer circuits (21, 22) feeding back an output of the differential amplifier to its input, wherein a temperature coefficient converter (5) converting an output voltage of a reference voltage generator (4) and its temperature dependence to a voltage having a predetermined voltage and temperature coefficient and outputting it is provided to control bias currents IEF of emitter follower circuits to be in proportion to temperature variation. There are a characteristic in which delay time of the emitter follower circuits constructing the buffer circuits is in inverse proportion to a transconductance of transistors and a characteristic in which the transconductance is in inverse proportion to temperature and is in proportion to the bias currents IEF.

Abstract: The present invention provides an optical transmitter using a multiplexer which can maintain a timing margin between a clock and data as an operating reference at an optimal value when data transmission speed, or data rate to be handled is changed.

Abstract: A large time constant is caused due to parasitic capacitance at an anode terminal of a photodetector of an optical receiver. Therefore, an optical receiver wherein a variable negative capacitor mainly including an NPN-type transistor operable at high speed is configured and is connected to the input terminal of a preamplifier to which the output of the photodetector is input so that parasitic capacitance caused in the photodetector and due to packaging is equivalently reduced and the fluctuation of parasitic capacitance caused due to manufacturing dispersion is also compensated is provided.

Abstract: There is provided not only a radio frequency power amplifier using an SiGe HBT subject to a little amplification distortion, but also a communication system using the same. A conventional radio frequency power amplifier provides base bias paths of transistors Q1 through QN (SiGe HBT) with bias resistors R11 through R1N having resistance values three to five times higher than those of a ballast resistor attached to each transistor's base. A coil LB is provided in parallel with the bias resistor as a means for compensating a voltage drop due to direct current component IDC flowing through the bias resistor. Addition of the bias resistor suppresses non-linearity of low-frequency variations in an output current. Addition of the coil compensates for voltage drop. Accordingly, the maximum linear output power can be improved. As a result, it is possible to provide the power amplifier subject to a little amplification distortion within a wide output range.

Abstract: An optical receiver generates a voltage signal having a predetermined swing from a current signal, and feeds the voltage signal to a decision circuit. An optical receiving element receives the input optical signal, converts the optical signal to a current signal, and provides the current signal to a preamplifier, which converts the input current signal into a voltage signal. The voltage signal is input to an amplifier having a limiting function, which linearly amplifies the voltage signal when the swing of the voltage signal is smaller than a predetermined value, and limitedly amplifies the voltage signal when the voltage signal is greater than the predetermined value. An automatic-gain-control amplifier receives the output from the amplifier with the limiting function, and amplifies the input voltage signal to a voltage signal having a constant swing.

Abstract: The invention provides a partially protected trisphenol having the general formula (I) wherein R1 is an alkyl group of 1-4 carbons or an alkoxyl group of 1-4 carbons, R2 is an alkyl group of 1-6 carbons or a cycloalkyl group of 5 or 6 carbons, X1 is a hydrogen atom, an alkoxycarbonylmethyl group wherein the alkyl group has 1-4 carbons, an alkoxycarbonyl group wherein the alkyl group has 1-4 carbons or a tetrahydropyranyl group, X2 is a hydrogen atom, an alkoxycarbonylmethyl group wherein the alkyl group has 1-4 carbons, an alkoxycarbonyl group wherein the alkyl group has 1-4 carbons or a tetrahydropyranyl group, provided that when X1 is a hydrogen atom, X2 is not a hydrogen atom, and when X2 is a hydrogen atom, X1 is not a hydrogen atom; and m is an integer of 0, 1 or 2, and n is an integer of 0, 1, 2 or 3.

Abstract: An optical receiver generates a voltage signal having a predetermined swing from a current signal, and feeds the voltage signal to a decision circuit. An optical receiving element receives the input optical signal, converts the optical signal to a current signal, and provides the current signal to a preamplifier, which converts the input current signal into a voltage signal. The voltage signal is input to an amplifier having a limiting function, which linearly amplifies the voltage signal when the swing of the voltage signal is smaller than a predetermined value, and limitedly amplifies the voltage signal when the voltage signal is greater than the predetermined value. An automatic-gain-control amplifier receives the output from the amplifier with the limiting function, and amplifies the input voltage signal to a voltage signal having a constant swing.

Abstract: An optical receiver generates a voltage signal having a predetermined swing from a current signal, and feeds the voltage signal to a decision circuit. An optical receiving element receives the input optical signal, converts the optical signal to a current signal, and provides the current signal to a preamplifier, which converts the input current signal into a voltage signal. The voltage signal is input to an amplifier having a limiting function, which linearly amplifies the voltage signal when the swing of the voltage signal is smaller than a predetermined value, and limitedly amplifies the voltage signal when the voltage signal is greater than the predetermined value. An automatic-gain-control amplifier receives the output from the amplifier with the limiting function, and amplifies the input voltage signal to a voltage signal having a constant swing.

Abstract: Disclosed is a static type memory cell with high immunity from alpha ray-induced soft errors. The memory cell has a coupling capacitance C.sub.c between two data storage nodes 1 and 2. The p-well (or p-substrate) in which the driver-MOS transistors MN3, MN4 and the transfer MOS transistors MN1, MN2 are formed is connected to a V.sub.bb generator. The voltage V.sub.bb is set lower than the low level V.sub.L of the memory cell signal potential. Even when the potential variation .DELTA.V.sub.L of the low-voltage side node 2 is large, the parasitic diode present between the n-type diffusion layer corresponding to the source or drain of MN1-MN4 and the p-well (or p-substrate) does not turn on. Erroneous operations can therefore be prevented.

Abstract: A semiconductor memory device has a primary memory cell array, a primary decoder having a first circuit producing an intermediate signal from an address signal and a second circuit producing a first cell selection signal from the intermediate signal for selectively driving a word line and a bit line, an auxiliary memory cell array having a plurality of memory cells, each being used for a defective memory cell found in the primary memory cell array, an auxiliary decoder connected to the primary decoder to receive the intermediate signal, a non-volatile memory for storing first information indicating that the primary memory cell array contains a defective memory cell from which a cell defect signal is produced and for storing second information indicating an address of the defective memory cell from which a defective cell address signal is produced, and a control circuit responsive to the cell defect signal and the defective cell address signal for producing a first control signal to be supplied to the second c

Abstract: An inter-network connection system wherein a local signaling network including gateway offices of at least two signaling networks to be interconnected is configured between the signaling networks to be interconnected, and the inter-network connection is carried out through the local signaling network.

Abstract: The invention discloses a connector for printed circuit board comprising a first contact piece with a spring contactor, a second contact piece with a spring contactor, and a body in which these spring contactors can be arranged at their positions deviated from each other in lengthwise direction and a printed circuit board can be inserted in and out obliquely between contact points of the spring contactors, characterized in that when the printed circuit board inserted obliquely in the body is situated in substantially horizontal state, the printed circuit board is tightly contacted with the contact points of the spring contactors, thereby electrical connection between the printed circuit board and the first and second contact pieces being exactly and appropriately insured over a long period irrespective of frequency in insertion in and out of the printed circuit board.

Abstract: The invention relates to a method of manufacturing a jack comprising a step of punching a sheet metal by which a plurality of contact piece elements to be individual contact pieces of a jack are formed into a state of being partially connected to one another and arranged in parallel, a step of bending both ends of each contact piece element downward, a step of cutting off each contact piece element arranged in parallel by a cutter to form individual contact pieces, and a step of forcedly incorporating each contact piece into a jack body positioned right under a punching stroke of the cutter positioned right under a punching stroke of the cutter used in the cutting step whereby a complete automatization of the manufacturing is attained, considerably increasing productivity and decreasing an equipment cost as much.