Abstract:
A wired transmission path includes first and second differential transmission paths. The first differential transmission path is composed of two strip lines, and the second differential transmission path is composed of two strip lines. Each of the strip lines of the first differential transmission path is disposed at an equal distance from the strip lines of the second differential transmission path. Thus, there is provided a wired transmission path including a plurality of differential transmission paths in such a manner so as to cancel crosstalk.
Abstract:
Crosstalk is suppressed low even when one surface of a multi-layer board seats a semiconductor integrated circuit of the BGA type and peripheral circuit components. Of a plurality of BGA bumps arranged on the back surface of a semiconductor integrated circuit chip, those BGA bumps (such as a high-frequency signal pin) to which peripheral circuit components need be mounted right close are arranged outer-most, and peripheral circuit components are then mounted right close to these BGA bumps. The BGA bumps one tier inner from the outer-most BGA bumps, which are to be used as grounding terminals, are connected with a wide inner-layer grounding wire pattern. Those BGA bumps (such as a logic control signal pin) to which peripheral circuit components need not be mounted right close are disposed further inward and connected with an inner-layer wire pattern which is located even deeper down from a front layer. This makes the grounding pattern held between the signal wire pattern and the control wire pattern and ensures isolation between these wire patterns, whereby it is possible to suppress leakage of a signal which could cause crosstalk.
Abstract:
A feedforward amplifier includes a first power splitter for dividing an input signal into two paths. The first path, in sequence, includes a first vector adjuster, a main amplifier, a second power splitter and a delay circuit. The second path, in sequence, includes a delay circuit, a distortion detecting power combiner, a second vector adjuster and an error amplifier. The distortion detecting power combiner combines a portion of a signal from the first path with a signal in the second path. Each vector adjuster adjusts amplitude and phase of a signal in each path. A distortion suppression power combiner synthesizes a signal in the first path with a signal in the second path. Control is included for stopping operation of the error amplifier or main amplifier based on a predetermined condition.
Abstract:
A high power amplifier has a first balun propagating a half of an input signal to an in-phase output terminal, and also propagating a fourth of the input signal to first and second opposite-phase output terminals, the signal propagated to the first and second opposite-phase output terminals lagging 180 degrees behind the signal propagated to the in-phase output terminal; first and second power amplifier circuits connected to the first and second opposite-phase output terminals of the first balun and having the same characteristics; a third power amplifier circuit connected to the in-phase output terminal of the first balun and having output power substantially twice as much as the output power of the first or second power amplifier circuit; and a second balun having first and second opposite-phase input terminals for receiving the outputs of the first and second power amplifier circuits, having an in-phase input terminal for receiving the output of the third power amplifier circuit, combining the outputs of the first, second and third power amplifier circuits, and propagating combined output.
Abstract:
To reduce the size of a multi-carrier transmitter circuit for a mobile communication base station, by suppressing instantaneous peak output power to a small value with respect to a wide-band signal of a few MHz to tens of MHz so that the peak factor of a multi-carrier signal is reduced. In a multi-carrier transmitter circuit for modulating carriers with corresponding input signals to generate modulated signals and then multiplexing said modulated signals and outputting a multiplexed signal, the multi-carrier transmitter circuit is equipped with carrier generators 3-1 to 3-n for generating each said carrier, modulators 5-1 to 5-n for modulating each carrier with each input signal and outputting said modulated signal, an adder 6 for multiplexing said modulated signals and outputting the multiplexed signal, variable attenuators 2-1 to 2-n for directly or indirectly adjusting a level of each input signal, phase detectors 4-1 to 4-n for detecting a phase of each carrier, and a control circuit 7 for controlling the variable attenuators 2-1 to 2-n in accordance with the phase of each carrier.
Abstract:
A delay circuit in which amplitude characteristic and delay time characteristic of the output signals do not have any ripple relative to the length of the transmission line is provided. The delay circuit includes a circuit that makes a part of signals distributed into two parts by the power divider (103) to be identical in amplitude and inverse in phase relative to the component of signals outputted from the terminal-a directly to the terminal-c of the circulator (104). By composing with the power combiner (107) both signals are offset each other at the output terminal. As a result, only the signals that are inputted from the input terminal (101) and transmitted through the circulator (104) and the open-ended transmission line (105) are outputted to the output terminal (102).
Abstract:
A power amplifier has an input terminal; an output terminal; an N number of bypassable amplification circuits which are connected directly or indirectly in a sequential manner between the input terminal and the output terminal; an impedance conversion circuit which is connected directly or indirectly between the amplification circuit of a final stage and the output terminal; and a bias control circuit which controls the amplification circuits, each of the amplification circuits is configured by a high-frequency switch circuit, and an amplifier which is connected directly or indirectly to the switch circuit, and the bias control circuit controls power source voltages of the amplifiers and controls status of the switch circuit.
Abstract:
A feedforward amplifier includes a power divider for dividing the input signal into first and second signals. The first signal is processed in a first path that includes, in sequence, a first vector adjuster, a main amplifier, a directional coupler and a delay circuit. The second signal is delayed in a second path that includes, in sequence, another delay circuit, a first power combiner and an auxiliary amplifier block. The first power combiner combines the first signal, by way of a coupling port from the directional coupler, with the second signal to provide a combined signal into the auxiliary amplifier block. The auxiliary amplifier block further divides the second signal into two divided signals, each having a respective non-overlapping frequency band. The two divided signals are respectively vector adjusted, amplified, and then recombined. The recombined signal is then recombined with the processed signal in the first path to provide the desired output signal.
Abstract:
A traffic sign for use in a paved road has a housing with an open upper end. A holder is vertically movably received in the housing. A light emitting unit is installed in the holder to move therewith. A transparent plate is mounted on the holder to move therewith. The transparent plate permits a light from the light emitting unit to transmit therethrough. A space is defined between a bottom of the housing and a lower end of the holder to permit the vertical movement of the holder in the housing. An elastic support ring has an inner wall fixed to an outer surface of the holder and an outer wall fixed to an inner surface of the housing. Projections are formed on the elastic support ring. Each projection projects upward beyond the transparent plate. Recesses are provided by the elastic support ring. Each recess is defined between the projections, so that the light from the light emitting unit is viewed through the transparent plate and each of the recesses.
Abstract:
A high power amplifier has a first balun propagating a half of an input signal to an in-phase output terminal, and also propagating a fourth of the input signal to first and second opposite-phase output terminals, the signal propagated to the first and second opposite-phase output terminals lagging 180 degrees behind the signal propagated to the in-phase output terminal; first and second power amplifier circuits connected to the first and second opposite-phase output terminals of the first balun and having the same characteristics; a third power amplifier circuit connected to the in-phase output terminal of the first balun and having output power substantially twice as much as the output power of the first or second power amplifier circuit; and a second balun having first and second opposite-phase input terminals for receiving the outputs of the first and second power amplifier circuits, having an in-phase input terminal for receiving the output of the third power amplifier circuit, combining the outputs of the first, second and third power amplifier circuits, and propagating combined output.