Nec Corporation

Renesas Electronics Corporation

Nec Compound Semiconductor Devices, Ltd.

Iwatani Sangyo Kabushiki Kaisha (Iwatani International Corporation)

Akira Kuwano

Yoshitaka Murata

Yoshimasa Kidowaki

Noriyuki Shinohara

Yoko Kawasumi

To extend the transmission distance with the voltage supply source and improve the communication performance of PLCs Solution. The power supply circuit includes a step-down DC/DC converter to which a voltage supplied from the power line is input and to which an input voltage is stepped down and output, a step-up/down DC/DC converter to which a voltage output from the step-down DC/DC converter or a voltage supplied from the power line is input and to which the input voltage is stepped up or stepped down and output to the power line communication circuit, a switch circuit for connecting an input of the step-up/down DC/DC converter to an output of the step-down DC/DC converter or power line, a voltage monitoring circuit for monitoring a voltage supplied from the power line, and a control circuit for controlling connection of the switch circuit based on the voltage value of the voltage supplied from the power line.

Power supply circuit, power supply system, and control method

A voltage controlled oscillator circuit comprises a variable current generator to supply an operation current to a voltage controlled oscillator, the voltage controlled oscillator to include a resonance circuit having a variable capacitor and inductor, and to output an output signal having an amplitude based on a current generated by the variable current generator, and a first optimization circuit to which the output signal is inputted, the first optimization circuit generating and outputting a current setting signal based on an amplitude change of the output signal corresponding to a change of a current outputted by the variable current generator to the variable current generator.

Voltage controlled oscillator

In a phase locked loop type frequency synthesizer including a phase/frequency comparator for receiving an input signal, a charge pump circuit, a loop filter for generating a control voltage, a voltage control oscillator block including a plurality of voltage controlled oscillators controlled by the control voltage, and a frequency divider formed by a fixed frequency divider and a programmable frequency divider, a selecting circuit selects and activates only one of the voltage controlled oscillators, and counts a number of output pulses of the first frequency divider within a predetermined number of output pulses of the input signal while applying a bias voltage to the loop filter. Thus, the one of the voltage controlled oscillators being selected so that the number of the output pulses of the first frequency divider is brought close to an optimum value.

Wide lock range phase locked loop and method of operation

An orthogonal modulator capable of eliminating an offset component between an I signal and a Q signal. The orthogonal modulator includes a generation circuit for generating a plurality of base band signals such as voice signal, a mixing circuit for mixing the base band signals and a plurality of carrier waves, an extraction circuit for extracting each DC offset component generated by the generation circuit or the mixing circuit, a comparison circuit for comparing the DC offset components thus extracted with each other, an addition circuit for adding a plurality of comparison results with other comparison results, and an offset elimination circuit for eliminating the DC offset components included in a plurality of addition signals by subtracting the DC offset components from the base band signals before they are applied to the mixing circuit.

Orthogonal modulator, mobile terminal and communication system

There is disclosed a 90-degree phase shifter so configured that an input signal is supplied through a variable gain amplifying circuit and a phase adjusting circuit to a low pass filter and also supplied through another variable gain amplifying circuit and another phase adjusting circuit to a high pass filter, so that the low pass filter and the high pass filter generate output signals, respectively, which have a 90-degree phase difference therebetween. An amplitude error and a phase error between the output signals are detected, so that the variable gain amplifying circuits are gain-controlled by the detected amplitude error, and the phase shift amounts of the phase adjusting circuits are controlled by the detected phase error. Thus, the amplitude error and the phase error attributable to the variation in the device characteristics and the parasite component can be removed, so that it is possible to obtain the output signals having the 90-degree phase difference with no amplitude error and no phase error.

90-degree phase shifter

In a mold material for use in molding a titanium cast to be mounted into the mouth as a dental prosthesis, magnesia and phosphate are added as a binder to its main ingredient composed of alumina and zirconia.

Growing community of inventors

Tokyo, Japan

Akira Kuwano