Abstract: A high-frequency power amplification electronic part is disclosed which comprises a power amplifier circuit and a bias control circuit, the power amplifier circuit having a plurality of amplifier stages for amplifying an input high-frequency signal, the bias control circuit acting to bias the power amplifier circuit. The power amplifier circuit controls output power in accordance with input power that is varied while a gain of the power amplifier circuit is being fixed by either a bias current or a bias voltage supplied from the bias control circuit.

Abstract: A GSM system and an EDGE system much different in gain are incorporated into a single high frequency power amplifier module. In a high frequency power amplifier module having a multi-stage amplifying configuration, which is used in a GSM mode and an EDGE mode according to switching, a first-stage amplifier comprises a dual gate MOSFET. In the EDGE mode, an APC signal or a selected and fixed potential is supplied to a first gate electrode of the dual gate MOSFET. Further, Vgs (Vgs1, Vgs2 and Vgs3) of respective transistors of from a first stage to a third stage are fixed in potential form or supplied as APC signals, and the gain in the EDGE mode is matched with that in the GSM mode, whereby the generation of noise is reduced.

Abstract: The present invention provides a high frequency amplifier using a power supply voltage regulate circuit for the purpose of compensating for variations in power supply voltage. The high frequency amplifier comprises three-stage power amplifiers which amplify an input signal and output the amplified signal, a bias circuit which supplies bias voltages for controlling these power amplifiers, a regulate circuit which compensates for variations in noise or gain with respect to the variations in the power supply voltage for driving the power amplifiers, etc. The regulate circuit holds constant an output voltage Vddc with respect to variations in power supply voltage Vdd and outputs the constant-held output voltage Vddc as a power supply voltage for the power amplifiers.

Abstract: A module including a bias circuit that generates gate bias voltages by resistance dividers creates a problem in that the values of the resistances constituting the bias circuit must be finely adjusted, and accordingly extra trimming tasks are required. The present invention provides current generators that generate currents varying with desired characteristics responsive to a control voltage, independent of variations in transistor threshold voltages, connects output resistors to parallel transistors in respective stages to form current mirror circuits, and supplies currents from the current generators thereto to drive them, instead of supplying dividing voltages.

Abstract: A multilayer wiring board having board having through holes in a thickness-wise direction, in which wiring board a semiconductor substrate mounted on the multi-layer wiring board has through holes in a thickness-wise direction, and entire areas, which the through holes in the semiconductor substrate occupy, in a plane orthogonal to the thickness-wise direction of the multilayer wiring board and of the semiconductor substrate are included in areas, which the through holes in the multilayer wiring board occupy.

Abstract: A GSM system and an EDGE system much different in gain are incorporated into a single high frequency power amplifier module.

Abstract: A semiconductor optical device fabricating method for easily fabricating on a single substrate a plurality of distributed feedback lasers or distributed Bragg reflector lasers with uniform static and dynamic properties and individually different oscillation wavelengths. A plurality of pairs of stripe type insulating thin film masks are formed over that region of the semiconductor substrate which has optical waveguides formed therein for the lasers. Each pair of stripe type masks has a constant gap therebetween. With the masks in place, optical waveguide layers for the lasers are grown in crystallized fashion through metal organic vapor epitaxy. The stripe type masks in pairs differ dimensionally from one another.

Abstract: A waveguide device includes an indium phosphide substrate, an active layer formed on the indium phosphide substrate, and a cladding layer formed on the active layer, the cladding layer having a ridge structure the side wall of which is configured into a reversed mesa form.

Abstract: A waveguide device includes an indium phosphide substrate, an active layer formed on the indium phosphide substrate, and a cladding layer formed on the active layer, the cladding layer having a ridge structure the side wall of which is configured into a reversed mesa form.

Abstract: A semiconductor optical device fabricating method for easily fabricating on a single substrate a plurality of distributed feedback lasers or distributed Bragg reflector lasers with uniform static and dynamic properties and individually different oscillation wavelengths. A plurality of pairs of stripe type insulating thin film masks are formed over that region of the semiconductor substrate which has optical waveguides formed therein for the lasers. Each pair of stripe type masks has a constant gap therebetween. With the masks in place, optical waveguide layers for the lasers are grown in crystallized fashion through metal organic vapor epitaxy. The stripe type masks in pairs differ dimensionally from one another.

Abstract: A pyrographic printer comprises an exhaust system having an elongated inlet and a bifurcated throat. The inlet is adjacent to and substantially coextensive with the path of travel for the stylus, and the throat is configured to define a main passage which leads away from the inlet and a branch passage which loops back toward the inlet. To increase the vacuum drawn in the immediate proximity of the stylus, the input impedance of the exhaust system is selectively reduced in that region. For that purpose, the stylus carriage carries a baffle which extends into the throat to more or less seal a stylus aligned segment of the branch passage.