Abstract: A radio-frequency module includes a mount board, an antenna terminal and a ground terminal, a low-noise amplifier, a first inductor, and a second inductor. The mount board has a first principal surface and a second principal surface on opposite sides of the mount board from one another. The low-noise amplifier includes a transistor configured to amplify a signal. The first inductor is disposed on one of the first principal surface and the second principal surface of the mount board. The first inductor is connected to the antenna terminal. The second inductor is disposed on the other of the first principal surface and the second principal surface of the mount board. The second inductor is connected between the transistor and the ground terminal.

Abstract: A first filter is a hybrid filter including an acoustic wave filter, a plurality of first inductors, and a plurality of first capacitors. A high frequency module further includes a metal electrode layer covering at least part of a resin layer and at least part of an outer peripheral surface of a mounting substrate. Among a plurality of inductors including the plurality of first inductors of the first filter and a plurality of second inductors of a second filter, at least one inductor (the second inductor) is a circuit element including a conductor pattern portion formed in the mounting substrate. The shortest distance between the outer peripheral surface of the mounting substrate and a signal terminal (a third signal terminal) connected to the circuit element is longer than the shortest distance between the outer peripheral surface of the mounting substrate and the circuit element.

Abstract: A radio-frequency module includes a mount board, an antenna terminal and a ground terminal, a low-noise amplifier, a first inductor, and a second inductor. The mount board has a first principal surface and a second principal surface on opposite sides of the mount board from one another. The low-noise amplifier includes a transistor configured to amplify a signal. The first inductor is disposed on one of the first principal surface and the second principal surface of the mount board. The first inductor is connected to the antenna terminal. The second inductor is disposed on the other of the first principal surface and the second principal surface of the mount board. The second inductor is connected between the transistor and the ground terminal.

Abstract: An RF front-end module includes power amplifiers, transmission-side filters, a reception-side filter, and a switch IC. A first transmission signal is output from a first transmission signal input terminal to a first common terminal via the power amplifier and the transmission-side filter. A second transmission signal is output from a second transmission signal input terminal to a second common terminal via the power amplifier and the transmission-side filter. A first reception signal input from the first common terminal and a second reception signal input from the second common terminal are input via the switch IC to the reception-side filter, common to the first and second reception signals, and are output from the reception-side filter to a reception signal output terminal.

Abstract: A circuit module and a measurement method enable accurate measurement of isolation characteristics of an isolator. The circuit module includes a processing circuit including SAW filters and a power amplifier and performs certain processing on an input signal. An isolator includes an input port, an output port and a ground port and outputs an input signal, which is input thereto via the input port and on which the processing circuit has performed the certain processing, as an output signal via the output port. A directional coupler distributes a signal transmitted between the processing circuit and the isolator. A measurement instrument inputs a test signal from the output port and measures a detection signal output from the directional coupler.

Abstract: An RF front-end module includes power amplifiers, transmission-side filters, a reception-side filter, and a switch IC. A first transmission signal is output from a first transmission signal input terminal to a first common terminal via the power amplifier and the transmission-side filter. A second transmission signal is output from a second transmission signal input terminal to a second common terminal via the power amplifier and the transmission-side filter. A first reception signal input from the first common terminal and a second reception signal input from the second common terminal are input via the switch IC to the reception-side filter, common to the first and second reception signals, and are output from the reception-side filter to a reception signal output terminal.

Abstract: A frequency-selective high-frequency oscillator includes a first switching circuit that controls the operation of a first amplifying circuit, and a second switching circuit that controls the operation of the first switching circuit and a second amplifying circuit. Switching control signals are input to the second switching circuit. When the switching control signal is “Low”, the second switching circuit turns ON and the second amplifying circuit only operates, thereby outputting a high frequency signal with a resonant frequency according to a second resonant circuit. On the other hand, when the switching control signal is “High”, the second switching circuit turns OFF and the first switching circuit turns ON, which causes the first amplifying circuit only to operate. Thus, a high frequency signal with a resonant frequency acceding to a first resonant circuit is output.

Abstract: A frequency-selective high-frequency oscillator includes a first switching circuit that controls the operation of a first amplifying circuit, and a second switching circuit that controls the operation of the first switching circuit and a second amplifying circuit. Switching control signals are input to the second switching circuit. When the switching control signal is “Low”, the second switching circuit turns ON and the second amplifying circuit only operates, thereby outputting a high frequency signal with a resonant frequency according to a second resonant circuit. On the other hand, when the switching control signal is “High”, the second switching circuit turns OFF and the first switching circuit turns ON, which causes the first amplifying circuit only to operate. Thus, a high frequency signal with a resonant frequency acceding to a first resonant circuit is output.

Abstract: In the path from the output of a charging pump to a control voltage terminal including the inside of a loop filter, voltage application means for applying a direct-current voltage of a predictable value to the control voltage terminal is given, resulting in a PLL circuit. In the PLL circuit, first, a fixed direct-current voltage is applied to the control voltage terminal from the voltage application means. The oscillation frequency of a voltage-controlled oscillator may be adjusted by making use of a trimming area as a oscillation frequency adjustment mechanism. Therefore, the oscillation frequency of the voltage-controlled oscillator can be quickly adjusted using fewer pieces of equipment.