Abstract: The number of components of a high frequency power amplifier is reduced. A bias resistance ratio is adjusted in accordance with a change in the threshold voltage Vth of a transistor. A high frequency power amplifier has a plurality of amplifying systems. Each of these systems has an input terminal to which a signal to be amplified is supplied, an output terminal, a bias terminal, a plurality of amplifying stages which are sequentially cascaded between the input and output terminals, and a bias circuit connected to the bias terminal and each of the amplifying stages to apply a bias potential to the amplifying stage. The amplifying stage includes a control terminal for receiving an input signal and the bias potential supplied to the stage and a first terminal for transmitting an output signal of the stage.

Abstract: An optical connector comprises a clamp member holding an optical fiber, a first housing to which the clamp member is fixed, and a second housing fitted to the first housing. The first housing has an aligning portion for aligning and positioning the optical fiber, and a clamp holding portion holding the clamp member. The optical fiber has an end portion protruding forward from the aligning portion in a cantilevered state.

Abstract: In a radio communication system wherein the detection of output level required for feedback control of output power is carried out by current detection, the stability of control loop and the response to change in request-to-send level are enhanced. An electronic component for high frequency power amplifier carries out the detection of output level, required for feedback control of the output power of a high frequency power amplification circuit, by current detection. The electronic component has an error amplifier. The error amplifier compares an output level detection signal with an output level instruction signal, and generates a signal for controlling the gain of the high frequency power amplification circuit according to the difference between them. For the error amplifier, a low-pass amplification circuit is used. The amplification circuit is provided with between its output terminal and its inverting input terminal with a phase compensation circuit.

Abstract: The present invention provides a high frequency power amplifier of an open-loop type, which outputs a signal having a level corresponding to an output level required under control of a power supply voltage for each output power FET, based on a control signal for the output level. The high frequency power amplifier is provided with a bias voltage generating circuit which generates a gate bias voltage of each output power FET according to an output voltage of a power control circuit for controlling the power supply voltage for the output power FET, based on the control signal for the output level.

Abstract: The number of components of a high frequency power amplifier is reduced. A bias resistance ratio is adjusted in accordance with a change in the threshold voltage Vth of a transistor.

Abstract: The present invention provides a high frequency power amplification circuit capable of preventing an output power and current consumption from being largely changed even when a load fluctuates in a wireless communication system for detecting an output level necessary for feedback control by a current detecting method. In a high frequency power amplification circuit as a component of a wireless communication system which detects an output level necessary for feedback control by a current detecting method, a capacitative element is interposed between the drain terminal of a power amplification transistor in the final stage and the gate terminal of a transistor constructing a current mirror circuit in a circuit for detecting an output level, and a change in an output power accompanying load fluctuation is reflected in a detection current of the output level detecting circuit.

Abstract: The present invention provides a high frequency power amplifier of an open-loop type, which outputs a signal having a level corresponding to an output level required under control of a power supply voltage for each output power FET, based on a control signal for the output level. The high frequency power amplifier is provided with a bias voltage generating circuit which generates a gate bias voltage of each output power FET according to an output voltage of a power control circuit for controlling the power supply voltage for the output power FET, based on the control signal for the output level.

Abstract: The present invention provides a high frequency power amplifier of an open-loop type, which outputs a signal having a level corresponding to an output level required under control of a power supply voltage for each output power FET, based on a control signal for the output level. The high frequency power amplifier is provided with a bias voltage generating circuit which generates a gate bias voltage of each output power FET according to an output voltage of a power control circuit for controlling the power supply voltage for the output power FET, based on the control signal for the output level.

Abstract: The number of components of a high frequency power amplifier is reduced. A bias resistance ratio is adjusted in accordance with a change in the threshold voltage Vth of a transistor. A high frequency power amplifier has a plurality of amplifying systems. Each of these systems has an input terminal to which a signal to be amplified is supplied, an output terminal, a bias terminal, a plurality of amplifying stages which are sequentially cascaded between the input and output terminals, and a bias circuit connected to the bias terminal and each of the amplifying stages to apply a bias potential to the amplifying stage. The amplifying stage includes a control terminal for receiving an input signal and the bias potential supplied to the stage and a first terminal for transmitting an output signal of the stage.

Abstract: A high frequency power amplifying device has two amplifying lines. Each amplifying line has a configuration in which a plurality of amplifying stages are connected in cascade having two source voltage terminals, of which one is connected to the first amplifying stage of one amplifying line and to the remaining amplifying stages of the other amplifying line, and the other, to the first amplifying stage of the latter amplifying line and to the remaining amplifying stages of the former amplifying line. An air core coil with a low D.C. resistance, formed by spirally winding a copper wire of about 0.1 mm in diameter, is connected in series between the final amplifying stage of each amplifying line and the source voltage terminal. Since there is no signal leak in each amplifying line from the final amplifying stage to the first amplifying stage and the D.C. resistance of the air core coil is low, oscillation margin can be improved.

Abstract: An intake manifold made of a synthetic resin includes a surge tank, and a plurality of intake pipes disposed in parallel to one another and each having a rising pipe portion which is connected to a lower portion of the surge tank and extends upwards. A space is defined between the surge tank and each of the rising pipe portions, as viewed sideways. In order to enable an increase in volume of the surge tank, while avoiding an increase in size of the intake manifold, the surge tank (20) includes a main tank portion (20a) extending in a direction (28) of arrangement of the intake pipes (21A to 21D) and opposed to the rising pipe portions (29A to 29D) of the intake pipes (21A to 21D), and a sideways-bulged portion (20b) which is bulged from an intermediate portion of the main tank portion (20a) as viewed in the arrangement direction (28) and is interposed between a pair of rising pipe portions (29B, 29C) disposed at the intermediate portion as viewed in the arrangement direction 28.

Abstract: The present invention provides a high frequency power amplifier of an open-loop type, which outputs a signal having a level corresponding to an output level required under control of a power supply voltage for each output power FET, based on a control signal for the output level. The high frequency power amplifier is provided with a bias voltage generating circuit which generates a gate bias voltage of each output power FET according to an output voltage of a power control circuit for controlling the power supply voltage for the output power FET, based on the control signal for the output level.

Abstract: The present invention provides a high frequency power amplifier of an open-loop type, which outputs a signal having a level corresponding to an output level required under control of a power supply voltage for each output power FET, based on a control signal for the output level. The high frequency power amplifier is provided with a bias voltage generating circuit which generates a gate bias voltage of each output power FET according to an output voltage of a power control circuit for controlling the power supply voltage for the output power FET, based on the control signal for the output level.

Abstract: An intake manifold made of a synthetic resin includes a surge tank, and a plurality of intake pipes disposed in parallel to one another and each having a rising pipe portion which is connected to a lower portion of the surge tank and extends upwards. A space is defined between the surge tank and each of the rising pipe portions, as viewed sideways. In order to enable an increase in volume of the surge tank, while avoiding an increase in size of the intake manifold, the surge tank (20) includes a main tank portion (20a) extending in a direction (28) of arrangement of the intake pipes (21A to 21D) and opposed to the rising pipe portions (29A to 29D) of the intake pipes (21A to 21D), and a sideways-bulged portion (20b) which is bulged from an intermediate portion of the main tank portion (20a) as viewed in the arrangement direction (28) and is interposed between a pair of rising pipe portions (29B, 29C) disposed at the intermediate portion as viewed in the arrangement direction 28.

Abstract: The number of components of a high frequency power amplifier is reduced. A bias resistance ratio is adjusted in accordance with a change in the threshold voltage Vth of a transistor.

Abstract: Disclosed herein is a high frequency power amplifier system having a transistor comprised of a first electrode, a second electrode and a control electrode and for controlling current which flows between the first electrode and the second electrode by applying a potential to the control electrode, and a resistance type potential divider circuit for determining a dc bias potential applied to the control electrode of the transistor, and wherein an input signal is inputted to the control electrode, an output signal is outputted from the first electrode and a control signal is inputted to the resistance type potential divider circuit. One resistor of the resistance type potential divider circuit is comprised of a temperature compensating resistor whose resistance value varies linearly, so that a temperature characteristic of an idle current defined as an output when the control signal is not inputted, assumes a negative temperature characteristic.

Abstract: Disclosed herein is a high frequency power amplifier system having a transistor comprised of a first electrode, a second electrode and a control electrode and for controlling current which flows between the first electrode and the second electrode by applying a potential to the control electrode, and a resistance type potential divider circuit for determining a dc bias potential applied to the control electrode of the transistor, and wherein an input signal is inputted to the control electrode, an output signal is outputted from the first electrode and a control signal is inputted to the resistance type potential divider circuit. One resistor of the resistance type potential divider circuit is comprised of a temperature compensating resistor whose resistance value varies linearly, so that a temperature characteristic of an idle current defined as an output when the control signal is not inputted, assumes a negative temperature characteristic.

Abstract: A bass-reflex type speaker system having a cabinet including a front baffle board, a back panel and two side panels and a speaker mounted on the front panel. A port is disposed in either the back panel or in one of the side panels and a duct is in communication with the port. The back panel may be flat or have a generally triangular cross-sectional configuration where the apex of the triangle is directed toward the speaker. Further, the speaker may be positioned in the approximate center of the front baffle board and the port positioned at the apex of the back panel. A beam may be provided extending across and spaced from the port, the beam having a triangular shaped tip directed toward and spaced from the port.