Abstract: Provided is a digital attenuation apparatus having ultra broadband and excellent attenuation characteristics. The digital attenuation apparatus includes an input port, an output port, a first transmission line, a second transmission line, a first switching device, a third transmission line, a first resistive element, a second resistive element, a fourth transmission line, a second switching device, a fifth transmission line, and a third resistive element.

Abstract: A tuning assembly for a radio frequency is disclosed. The tuning assembly includes: a tuning screw grasping unit integrally formed with a main body of the filter, which includes a tuning screw receiving unit and a fastening member for grasping a tuning screw; and a tuning screw inserted into the filter through the tuning screw receiving unit, wherein the filter is finely tuned by inserting the tuning screw into the filter through the tuning screw receiving unit and a female screw unit formed at the filter.

Abstract: Provided is a digital attenuation apparatus having ultra broadband and excellent attenuation characteristics. The digital attenuation apparatus includes an input port, an output port, a first transmission line, a second transmission line, a first switching device, a third transmission line, a first resistive element, a second resistive element, a fourth transmission line, a second switching device, a fifth transmission line, and a third resistive element.

Abstract: A tuning assembly for a radio frequency is disclosed. The tuning assembly includes: a tuning screw grasping unit integrally formed with a main body of the filter, which includes a tuning screw receiving unit and a fastening member for grasping a tuning screw; and a tuning screw inserted into the filter through the tuning screw receiving unit, wherein the filter is finely tuned by inserting the tuning screw into the filter through the tuning screw receiving unit and a female screw unit formed at the filter.

Abstract: A power amplifier for use in a mobile handset includes an amplifying transistor, a bias circuit including a bias transistor, the bias circuit providing a bias current to bias the amplifying transistor, and a bias current control circuit, responsive to fluctuation in a reference voltage and variation in temperature, for adjusting the bias current to control an operation current of the amplifying transistor.

Abstract: An adaptive bias circuit is provided for an amplifier module including a RF power amplifier for amplifying an input signal to generate an output signal, wherein the bias circuit receives the input signal to adjust a driving current to control a quiescent current of the RF power amplifier. The adaptive bias circuit includes means for providing the driving current to the bias circuit and means for drawing a bypass current from the providing means to reduce the driving current in response to the input signal, wherein the quiescent current is reduced when the driving current is reduced and the bypass current increases when the input signal is reduced.

Abstract: An adaptive bias circuit is provided for an amplifier module including a RF power amplifier for amplifying an input signal to generate an output signal, wherein the bias circuit receives the input signal to adjust a driving current to control a quiescent current of the RF power amplifier. The adaptive bias circuit includes means for providing the driving current to the bias circuit and means for drawing a bypass current from the providing means to reduce the driving current in response to the input signal, wherein the quiescent current is reduced when the driving current is reduced and the bypass current increases when the input signal is reduced.

Abstract: A power amplifier for use in a mobile handset includes an amplifying transistor for generating an output of the mobile handset, a bias circuit having a bias transistor and providing a bias current to bias the amplifying transistor, and a bias current control circuit, responsive to a control signal, for adjusting the bias current to control an operation current of the amplifying transistor. The control signal is generated by the mobile handset, and the control signal is determined by a power level of the output of the mobile handset.

Abstract: A power amplifier for use in a mobile handset includes an amplifying transistor, a bias circuit including a bias transistor, the bias circuit providing a bias current to bias the amplifying transistor, and a bias current control circuit, responsive to fluctuation in a reference voltage and variation in temperature, for adjusting the bias current to control an operation current of the amplifying transistor.

Abstract: A bias control circuit for a power amplifier including an RF amplifier having a transistor for power amplification, comprises two components. A first component is a bias circuit having an active bias transistor operating in an active mode and connected to a predetermined Vref pin to provide the transistor for power amplification with a base current and a second component is a bias current control circuit having another active bias transistor connected to a predetermined Vcon pin and turned on or off depending on a high or a low mode of the Vcon pin to thereby control a base current and a quiescent current of the transistor for power amplification.

Abstract: A power amplifier for use in a mobile handset includes an amplifying transistor for generating an output of the mobile handset, a bias circuit having a bias transistor and providing a bias current to bias the amplifying transistor, and a bias current control circuit, responsive to a control signal, for adjusting the bias current to control an operation current of the amplifying transistor. The control signal is generated by the mobile handset, and the control signal is determined by a power level of the output of the mobile handset.

Abstract: A bias control circuit for a power amplifier including an RF amplifier having a transistor for power amplification, comprises two components. A first component is a bias circuit having an active bias transistor operating in an active mode and connected to a predetermined Vref pin to provide the transistor for power amplification with a base current and a second component is a bias current control circuit having another active bias transistor connected to a predetermined Vcon pin and turned on or off depending on a high or a low mode of the Vcon pin to thereby control a base current and a quiescent current of the transistor for power amplification.