Abstract: A steel joined body includes a plurality of steels joined together, the plurality of steels including a joint interface having a carbon concentration of 0.20 mass % or more and 2.10 mass % or less, and the steel joined body including a concentration gradient layer having a carbon concentration decreasing with distance from the joint interface.

Abstract: A steel joined body includes a plurality of steels joined together, the plurality of steels including a joint interface having a carbon concentration of 0.20 mass % or more and 2.10 mass % or less, and the steel joined body including a concentration gradient layer having a carbon concentration decreasing with distance from the joint interface.

Abstract: A direction indicating device according to an embodiment includes: an orientation sensor that detects an orientation; a wireless communication device that receives orientation information; and a light emitting device. Furthermore, the direction indicating device includes a processor that controls the direction of light, generated by the light emitting device, in accordance with the angle that is formed by the detected orientation and the direction that is indicated by the received orientation information.

Abstract: A modulation mixer includes a low cost circuit for reducing a carrier frequency leak. An orthogonal modulator including the modulation mixer may be formed on a single silicon substrate and does not need to be connected to an external transformer to suppress carrier frequency leak.

Abstract: A double balanced mixer which may be used in communications devices, such as portable or cellular telephones. The mixer includes a first differential amplifier having a first transistor pair whose emitters are connected together, a second differential amplifier having a second transistor pair whose emitters are connected together, and a third differential amplifier having a third transistor pair whose emitters are connected together by way of a resistor. A first constant current source is connected between the emitter of one of the transistors of the third transistor pair and ground. A second constant current source is connected between the emitter of the other transistor of the third transistor pair and ground. A gate circuit is connected to one of the first and second current sources for selectively activating the one connected current source. By selectively activating the current source, the mixer has low power consumption.

Abstract: A semiconductor device having multiple circuit elements capable of performing different functions and that operate at a high frequency includes island regions on which the circuit elements are located and isolation regions that surround the island regions and thus, the circuit elements. The island regions electrically separate the circuit elements from each other. A capacitor is connected between a substrate portion of the semiconductor device and ground. The isolation regions include a conductive region with a conductivity type opposite to the conductivity type of the substrate portion, such that a parasitic capacitor is formed between the substrate portion and the conductive region. The parasitic capacitor prevents signal leakage between the circuit elements and the island regions.

Abstract: A phase shifter that may be used in a quadrature modulator or an image suppression mixer. The phase shifter includes a low pass filter that receives an input signal and generates a first carrier signal. A high pass filter also receives the input signal and generates a second carrier signal. A phase difference detection circuit connected to the high and low pass filters receives the first and second carrier signals and generates a control signal based on the phase difference between the carrier signals. The control signal is fed back to at least one of the low pass filter and the high pass filter to compensate for phase errors caused by parasitic capacitance. The phase shifter has a small circuit area and is very accurate, allowing it to be used in communications devices.

Abstract: A modulator that effectively suppresses carrier leakage is disclosed. The modulator includes a frequency multiplier, a phase shifter and an orthogonal modulator. The frequency multiplier outputs complementary signals whose frequencies are twice the frequency of a first carrier signal. The phase shifter divides the frequencies of the output signals of the frequency multiplier to produce a plurality of second carrier signals whose phases are shifted by 90 degrees from one another. The orthogonal modulator receives an input signal and the second carrier signals from the phase shifter and outputs signals obtained by combining the input signal with the second carrier signals. The frequency multiplier has an input circuit section including a differential circuit. The differential input section receives complementary signals as the first carrier signal. The orthogonal modulator has an output circuit section including a differential circuit.