Abstract: A fine-adjustment synthesizer includes a fractional phase-locked loop having a reference integer frequency divider, a phase comparator, a loop filter, a frequency variable oscillator, a mixer, a baud-pass filter, and a feedback path programmable fractional frequency divider. A coarse-adjustment synthesizer includes an integer-type phase-locked loop having a reference integer frequency divider, a phase comparator, a loop filter, a frequency variable oscillator, a band-pass filter, and a feedback path programmable integer frequency divider. An output of a reference signal source is input in parallel to both the fine-adjustment synthesizer and the coarse-adjustment synthesizer. An output of the frequency variable oscillator in the fine-adjustment synthesizer and an output of the frequency variable oscillator in the coarse-adjustment synthesizer are guided to the mixer and an output signal of the fine-adjustment synthesizer is guided to an output end.

Abstract: A fine-adjustment synthesizer includes a fractional phase-locked loop having a reference integer frequency divider, a phase comparator, a loop filter, a frequency variable oscillator, a mixer, a hand-pass filter, and a feedback path programmable fractional frequency divider. A coarse-adjustment synthesizer includes an integer-type phase-locked loop having a reference integer frequency divider, a phase comparator, a loop filter, a frequency variable oscillator, a band-pass filter, and a feedback path programmable integer frequency divider. An output of a reference signal source is input in parallel to both the fine-adjustment synthesizer and the coarse-adjustment synthesizer. An output of the frequency variable oscillator in the fine-adjustment synthesizer and an output of the frequency variable oscillator in the coarse-adjustment synthesizer are guided to the mixer and an output signal of the fine-adjustment synthesizer is guided to an output end.

Abstract: It is an object to attain both high gain and a broad band (that is, to attain both reduction in a gate-drain capacitance and reduction in a source-drain capacitance). Provided is a semiconductor device, including: a GaN channel layer (3) through which electrons travel; a barrier layer (4) which is provided on the GaN channel layer in order to form two-dimensional electron gas in the GaN channel layer and which contains at least any one of In, Al, and Ga and contains N; a gate electrode (8), a source electrode (6), and a drain electrode (7); and a plate (20) formed of a material having polarization, which is provided between the gate electrode (8) and the drain electrode (7), the plate being held in contact with a part of the barrier layer (4).

Abstract: A variable frequency amplifier includes a main amplifier system 4 for amplifying one of signals into which an input signal is split by a directional coupler 3 to output the amplified signal, and an injection amplifier system 9 for adjusting at least one of the amplitude and phase of the other one of the signals into which the input signal is split by the directional coupler 3 according to a setting provided thereto from outside the variable frequency amplifier, and for amplifying the other signal and injecting this amplified signal into an output side of the main amplifier system 4.

Abstract: Provided is a low distortion amplifier which can satisfy both securement of a setting space in a vicinity of a transistor and low impedance. The low distortion amplifier includes a short stub having a leading end thereof short-circuited with a high-frequency short-circuit element and a low-frequency short-circuit element, in which the short stub is connected to a vicinity of at least one of a gate terminal and a drain terminal of the transistor, and includes a plurality of branched lines, the plurality of branched lines each having a leading end thereof short-circuited with the high-frequency short-circuit element and the low-frequency short-circuit element.

Abstract: A directional coupler capable of improving a directionality of a directional coupler body including four terminals. The directional coupler includes a directional coupler body including the four terminals of an input port, an output port, a coupling port, and an isolation port; and a combiner for combining powers of an output signal of the coupling port and an output signal of the isolation port of the directional coupler body; and a directionality improving circuit for amplifying or attenuating at least one of the output signal of the coupling port and the output signal of the isolation port before outputting the same, and the combiner combines powers of the output signals amplified or attenuated by the directionality improving circuit.

Abstract: A variable frequency amplifier includes a main amplifier system 4 for amplifying one of signals into which an input signal is split by a directional coupler 3 to output the amplified signal, and an injection amplifier system 9 for adjusting at least one of the amplitude and phase of the other one of the signals into which the input signal is split by the directional coupler 3 according to a setting provided thereto from outside the variable frequency amplifier, and for amplifying the other signal and injecting this amplified signal into an output side of the main amplifier system 4.

Abstract: Provided is a power amplification device including: a DC power supply that outputs a drain voltage; a Doherty amplifier including a carrier amplifier and a peak amplifier, which are connected in parallel, and amplifies an RF signal; a voltage control circuit that outputs a first instruction to output a low voltage when an output power is equal to or lower than a given value, and outputs a second instruction to output a high voltage when the output power is larger than the given value; and a voltage converter circuit that converts the drain voltage to a voltage lower than the drain voltage and applies the converted voltage to drain terminals of the carrier amplifier and the peak amplifier according to the first instruction, and applies the drain voltage directly to the drain terminals of the carrier amplifier and the peak amplifier according to the second instruction.

Abstract: Provided is a low distortion amplifier which can satisfy both securement of a setting space in a vicinity of a transistor and low impedance. The low distortion amplifier includes a short stub having a leading end thereof short-circuited with a high-frequency short-circuit element and a low-frequency short-circuit element, in which the short stub is connected to a vicinity of at least one of a gate terminal and a drain terminal of the transistor, and includes a plurality of branched lines, the plurality of branched lines each having a leading end thereof short-circuited with the high-frequency short-circuit element and the low-frequency short-circuit element.

Abstract: A directional coupler capable of improving a directionality of a directional coupler body including four terminals. The directional coupler includes a directional coupler body including the four terminals of an input port, an output port, a coupling port, and an isolation port; and a combiner for combining powers of an output signal of the coupling port and an output signal of the isolation port of the directional coupler body; and a directionality improving circuit for amplifying or attenuating at least one of the output signal of the coupling port and the output signal of the isolation port before outputting the same, and the combiner combines powers of the output signals amplified or attenuated by the directionality improving circuit.

Abstract: Provided is a power amplification device including: a DC power supply that outputs a drain voltage; a Doherty amplifier including a carrier amplifier and a peak amplifier, which are connected in parallel, and amplifies an RF signal; a voltage control circuit that outputs a first instruction to output a low voltage when an output power is equal to or lower than a given value, and outputs a second instruction to output a high voltage when the output power is larger than the given value; and a voltage converter circuit that converts the drain voltage to a voltage lower than the drain voltage and applies the converted voltage to drain terminals of the carrier amplifier and the peak amplifier according to the first instruction, and applies the drain voltage directly to the drain terminals of the carrier amplifier and the peak amplifier according to the second instruction.

Abstract: When an input signal level is small, the electrical length of a phase line 21 and the electrical length of a phase line 23 are set in such a manner that the impedance seen by looking into the output side from an impedance reference point 11 at the output side of a carrier amplifier 3 becomes 2R+? (where R is a load resistance and ? is positive), and the electrical length of a phase line 22 is set at a difference between the electrical length of the phase line 21 and the electrical length of the phase line 23.

Abstract: When an input signal level is small, the electrical length of a phase line 21 and the electrical length of a phase line 23 are set in such a manner that the impedance seen by looking into the output side from an impedance reference point 11 at the output side of a carrier amplifier 3 becomes 2R+? (where R is a load resistance and ? is positive), and the electrical length of a phase line 22 is set at a difference between the electrical length of the phase line 21 and the electrical length of the phase line 23.

Abstract: A linearizer changes a gain characteristic to a valley characteristic in which a gain reduces and then increases. The linearizer includes: a signal path in which an RF signal input terminal an input side bias blocking capacitor, a diode pair, including diodes having opposite polarities to each other, an output side bias blocking capacitor and an RF signal output terminal in series in the stated order; a bias circuit in which a resistor is provided between and a signal path formed between the input side bias blocking capacitor and the diode pair and a bias terminal; an RF short-circuiting capacitor whose one end is connected with the bias circuit between the bias terminal and the resistor and whose other end is grounded; and a DC feed inductor whose one end is connected with the signal path between the diode pair and the output side bias blocking capacitor and whose other end is grounded.

Abstract: A T-type circuit having series resistors and a parallel resistor is arranged on the outside of an amplifier, a signal is amplified in the amplifier while stabilizing the signal by using the T-type circuit functioning as a stabilizing circuit, and the amplified signal is output. In this case, values of the series resistors and the parallel resistor of the T-type circuit are determined so as to set an output load impedance obtained by seeing the output side of the high-frequency amplifier from the amplifier to a value near to or slightly lower than a value of the conjugate complex impedance of an output impedance of the amplifier. Therefore, the output signal having a high output electric power and a low distortion can be obtained in the high-frequency amplifier while keeping a gain and a noise characteristic of the high-frequency amplifier.

Abstract: The present invention relates to a method of producing a superconducting composite wire. The method comprises forming a continuously supplied metal or metal alloy strip into a flume-shaped strip. A ceramic copper oxide superconducting powder material is filled in the interior of the flume-shaped strip. The flume-shaped strip is rolled such that a first edge of the strip approaches a second edge of the strip to form a tubing having a gap between the first and second edges and also having the powder material enveloped therein. The gap allows free access of oxygen to the powder material during a subsequent sintering step. The powder material is then sintered at a temperature of between 0 and 100.degree. C. less than the lowest melting point of any constituent of the material. The strip enveloping the sintered material is then deformed to a reduced cross-section and subjected to a heat treatment.

Abstract: A method of producing single crystals is characterized in that in withdrawing a semiconductor or dielectric material from its molten state while allowing it to grow into a single crystal solid, a die heated to a temperature higher than the solidifying point of the melt is disposed at the melt withdrawing outlet and the single crystal is withdrawn through the die.

Abstract: A powder-in-tube method of producing an oxide superconduction wire is disclosed in which a preformed copper oxide superconducting powder is continuously filled into a tube precursor having a U shape cross-section formed from a long strip of metal material. The tube precursor is formed into a tube by bending and welding. The resulting tube is drawn to a reduced cross-section and further heated to sinter the packed powder to form the finished oxide superconducting wire.

Abstract: A method and apparatus for continuously withdrawing an elongated product such as from a melt a fine wire is based on the rotating liquid medium spinning method. A layer of cooling liquid (14) is centrifugally formed on the inner peripheral surface of a rotational drum (13). Disposed inside the rotational drum (13) is a winding reel (19) having a rotating winding peripheral surface (18). A holder element (20) adapted to be magnetically attracted to the winding peripheral surface (18) is initially placed on the inner peripheral surface of the rotational drum (13). A molten material injected into the drum by a nozzle (16) is quenched for solidification in the cooling liquid (14) to form the product. Initially, the leading end emerging from the nozzle rides over the holder element (20) which then carries the leading end onto the winding peripheral surface (18) and holds it thereon by magnetic attraction.

Abstract: A heat-resistant aluminum alloy for electrical use, having high heat resistance and conductivity, obtained by subjecting an Al-Zr alloy comprising 0.23-0.35% Zr, the balance consisting of ordinary impurities and aluminum, to melting, casting, hot rolling in the state of high temperature or continuous heating, cold working to a predetermined size, ageing at a temperature within the range of 310.degree. C.-390.degree. C. for 50-400 hours so that Al.sub.3 Zr is dispersed uniformly and in fine particles, and, optionally, further cold working to a degree not exceeding 30% of reduction of area. The resultant aluminum alloy has conductivity in excess of 58% IACS, same strength as 1350 aluminum wire, and 10% softening temperature higher than 400.degree. C. at one hour annealing.