摘要:
A bias current to be supplied to an amplification circuit 60 is drawn out of a collector of a transistor Q11 of a bias circuit 10. The drawn-out bias current is input to a base of a transistor Q13 via an attenuation filter F2 and is output from an emitter of the transistor Q13 in the state where the voltage thereof is reduced by a level corresponding to Vbe. The attenuation filter F2 is conducted in a DC manner, and attenuates a component of a frequency fH(=2ft−fr) defined by a transmission frequency ft and a receiving frequency fr of a radio frequency signal. The bias current output from the emitter of the transistor Q13 is supplied to the amplification circuit 60 via an attenuation filter F1. The attenuation filter F1 is conducted in a DC manner, and attenuates a component of a frequency fL(=|fr−ft|).
摘要:
A bias voltage is applied via a first resistance to the base of a first transistor, and a radio frequency signal is input via a first capacitor to the base of the first transistor. The bias voltage is applied via a second resistance to the base of a second transistor. The bias voltage is applied via a third resistance to the base of a third transistor, and the radio frequency signal RF is input via a third capacitor to the base of the third transistor. A first band rejection filter is provided between the base of the first transistor and the base of the second transistor. A second band rejection filter is provided between the base of the second transistor and the base of the third transistor. The collectors of the first to third transistors are connected in common and the emitters thereof are all grounded.
摘要:
A bias voltage is applied via a first resistance to the base of a first transistor, and a radio frequency signal is input via a first capacitor to the base of the first transistor. The bias voltage is applied via a second resistance to the base of a second transistor. The bias voltage is applied via a third resistance to the base of a third transistor, and the radio frequency signal RF is input via a third capacitor to the base of the third transistor. A first band rejection filter is provided between the base of the first transistor and the base of the second transistor. A second band rejection filter is provided between the base of the second transistor and the base of the third transistor. The collectors of the first to third transistors are connected in common and the emitters thereof are all grounded.
摘要:
A bias current to be supplied to an amplification circuit 60 is drawn out of a collector of a transistor Q11 of a bias circuit 10. The drawn-out bias current is input to a base of a transistor Q13 via an attenuation filter F2 and is output from an emitter of the transistor Q13 in the state where the voltage thereof is reduced by a level corresponding to Vbe. The attenuation filter F2 is conducted in a DC manner, and attenuates a component of a frequency fH(=2ft−fr) defined by a transmission frequency ft and a receiving frequency fr of a radio frequency signal. The bias current output from the emitter of the transistor Q13 is supplied to the amplification circuit 60 via an attenuation filter attenuates a component of a frequency fL(=|fr−ft|).
摘要:
A first FET is inserted in a series position between a signal input terminal and a signal output terminal, while second and third FETs are inserted in a shunt position respectively between the signal input terminal and a ground terminal and between the signal output terminal and a ground terminal. First and second reference voltage terminals and a control terminal are provided. A first reference voltage and a control voltage are applied to the first FET, while a second reference voltage and a control voltage are applied respectively to the second and third FETs, so that the first, second, and third FETs serve as variable resistors. As such, a gain control circuit is constructed. Further, a first resistor is provided in parallel to the first FET, while second and third resistors are provided respectively in series to the second and third FETs.
摘要:
A first FET is inserted in a series position between a signal input terminal and a signal output terminal, while second and third FETs are inserted in a shunt position respectively between the signal input terminal and a ground terminal and between the signal output terminal and a ground terminal. First and second reference voltage terminals and a control terminal are provided. A first reference voltage and a control voltage are applied to the first FET, while a second reference voltage and a control voltage are applied respectively to the second and third FETs, so that the first, second, and third FETs serve as variable resistors. As such, a gain control circuit is constructed. Further, a first resistor is provided in parallel to the first FET, while second and third resistors are provided respectively in series to the second and third FETs.
摘要:
The present invention relates to an amplifier having high amplification efficiency. Amplification efficiency at low output is improved by reducing current at a latter stage depending on output power at the time when output power is reduced by gain control. In order to accomplish this improvement, gain control voltage applied to a gain control circuit for controlling the gain of a signal-amplifying field-effect transistor in a former stage is also applied simultaneously to a bias voltage control circuit for controlling the voltage between the gate and source of a signal-amplifying field-effect transistor in the latter stage, the voltage between the gate and source of the signal-amplifying field-effect transistor in the latter stage is controlled depending on the gain of the signal-amplifying field-effect transistor in the former stage to control the current between the drain and source of the signal-amplifying field-effect transistor in the latter stage. When the gain of the signal-amplifying field-effect transistor in the former stage is reduced, the current between the drain and source of the signal-amplifying field-effect transistor in the latter stage is reduced, whereby the efficiency of the amplifier is maintained high even when the output is low.
摘要:
A first FET is inserted in a series position between a signal input terminal and a signal output terminal, while second and third FETs are inserted in a shunt position respectively between the signal input terminal and a ground terminal and between the signal output terminal and a ground terminal. First and second reference voltage terminals and a control terminal are provided. A first reference voltage and a control voltage are applied to the first FET, while a second reference voltage and a control voltage are applied respectively to the second and third FETs, so that the first, second, and third FETs serve as variable resistors. As such, a gain control circuit is constructed. Further, a first resistor is provided in parallel to the first FET, while second and third resistors are provided respectively in series to the second and third FETs.
摘要:
A gain control circuit 12 comprises an FET 41 operating as a variable resistor. A gate terminal of the FET 41 is supplied with a control voltage VC applied to a gain control terminal 23. A source terminal and a drain terminal of the FET 41 are supplied with a reference voltage Vref1 obtained by a reference voltage circuit 13. The reference voltage Vref1 is controlled so as to compensate for a variation in the threshold voltage of the FET 41. The resistance value of the FET 41 is changed in accordance with the control voltage VC, and thus the gain of the high frequency amplification circuit 10 is also continuously changed.
摘要翻译:增益控制电路12包括作为可变电阻器操作的FET 41。 FET 41的栅极端子被提供有施加到增益控制端子23的控制电压VC。 FET 41的源极端子和漏极端子被提供有由参考电压电路13获得的参考电压Vref 1。 控制参考电压Vref 1以便补偿FET41的阈值电压的变化。 FET41的电阻值根据控制电压VC而变化,高频放大电路10的增益也不断变化。
摘要:
A first FET is inserted in a series position between a signal input terminal and a signal output terminal, while second and third FETs are inserted in a shunt position respectively between the signal input terminal and a ground terminal and between the signal output terminal and a ground terminal. First and second reference voltage terminals and a control terminal are provided. A first reference voltage and a control voltage are applied to the first FET, while a second reference voltage and a control voltage are applied respectively to the second and third FETs, so that the first, second, and third FETs serve as variable resistors. As such, a gain control circuit is constructed. Further, a first resistor is provided in parallel to the first FET, while second and third resistors are provided respectively in series to the second and third FETs.