Abstract: There is provided a dump truck that, when drive wheels (6) slip, is capable of reducing braking torques for the drive wheels (6) to avoid locking of the drive wheels (6), and of generating braking torques for driven wheels (7) to ensure an overall braking torque for the vehicle.

Abstract: The invention relates to a terminal structure of an electronic component, such as a tuner, in which a printed circuit board 1 on which electronic components including a pin header 2 having a plurality of pin terminals, and a case frame 3 housing the printed circuit board and having a notch opening exposing the pin terminals are provided. A guide hole 23 that penetrates from the upper surface of the pin header 2 to its lower surface in contact with the printed circuit board, and a guide axis 33—insertable into the guide hole 23—provided in a press portion 32 are provided, such that the pin header is held between the press portion 32 provided in the case frame 3 and the printed circuit board, enabling the pin header, even a slim, compact one, having a plurality of pin terminals to be fixed accurately to a predetermined position on the board with a predetermined posture.

Abstract: Provided is a tuner unit, including: a shield case (31) including a plurality of side walls surrounding a circuit board (2) on which an electronic component (21) is mounted, and a flat plate portion (314) that is integrated with at least one of the side walls and is arranged to be opposed to the circuit board (2); and an external connection terminal (4) fixed to the flat plate portion (314), in which the shield case (31) includes a first area, in which the flat plate portion (314) is arranged, and a second area surrounding a portion of the circuit board (2) mounted with the electronic component (21). The flat plate portion (314) includes an external connection terminal fixing portion (315) including at least three projections (317) that are held in contact with the external connection terminal (4).

Abstract: The invention relates to a terminal structure of an electronic component, such as a tuner, in which a printed circuit board 1 on which electronic components including a pin header 2 having a plurality of pin terminals, and a case frame 3 housing the printed circuit board and having a notch opening exposing the pin terminals are provided. A guide hole 23 that penetrates from the upper surface of the pin header 2 to its lower surface in contact with the printed circuit board, and a guide axis 33—insertable into the guide hole 23—provided in a press portion 32 are provided, such that the pin header is held between the press portion 32 provided in the case frame 3 and the printed circuit board, enabling the pin header, even a slim, compact one, having a plurality of pin terminals to be fixed accurately to a predetermined position on the board with a predetermined posture.

Abstract: A high frequency unit (e.g., an RF signal selection switch) includes, as its external terminals, a terrestrial input terminal, a CATV input terminal, an RF output terminal, a selection signal terminal, a power supply terminal and a ground potential terminal. The external terminals are attached to a shielding case surrounding the peripheral edge of a wiring substrate. The shielding plate is disposed in contact with the rear face of the wiring substrate.

Abstract: A signal selector selects one of a ground wave digital signal and a digital cable television signal in accordance with program selection information and transmits the selected signal to a shared tuner circuit. The shared tuner circuit selects only a signal of a desired channel from a signal output from the signal selector and converts the selected signal to an IF signal. An 8VSB and QAM demodulation circuit receives the IF signal from the shared tuner circuit and demodulate the signal in an 8VSB or QAM system to generate a transport stream. Thus a tuner for ground wave digital broadcasting and that for digital CATV broadcasting can be implemented as a shared tuner circuit surrounded by a single casing.

Abstract: A signal distribution device that is provided in a tuner of the present invention includes a plurality of demodulators, a voltage comparator, a switch, a broadband amplifier, and a balun. This allows the signal distribution device of the present invention to realize a signal distribution device capable of controlling a level of a signal that a distributor outputs.

Abstract: A frequency conversion apparatus has a high-frequency amplifier for amplifying an input high-frequency signal, a mixer for mixing the output signal of the high-frequency amplifier with a local oscillation signal, a filter for restricting the band of the output signal of the mixer to permit passage of only components within a predetermined band, and a variable filter provided between the high-frequency amplifier and the mixer and having a controllable cut-off frequency. With this configuration, it is possible to reduce back talk at low cost without inviting variation of input return loss characteristics.

Abstract: A high frequency unit (e.g., an RF signal selection switch) includes, as its external terminals, a terrestrial input terminal, a CATV input terminal, an RF output terminal, a selection signal terminal, a power supply terminal and a ground potential terminal. The external terminals are attached to a shielding case surrounding the peripheral edge of a wiring substrate. The shielding plate is disposed in contact with the rear face of the wiring substrate.

Abstract: A signal selector selects one of a ground wave digital signal and a digital cable television signal in accordance with program selection information and transmits the selected signal to a shared tuner circuit. The shared tuner circuit selects only a signal of a desired channel from a signal output from the signal selector and converts the selected signal to an IF signal. An 8VSB and QAM demodulation circuit receives the IF signal from the shared tuner circuit and demodulate the signal in an 8VSB or QAM system to generate a transport stream. Thus a tuner for ground wave digital broadcasting and that for digital CATV broadcasting can be implemented as a shared tuner circuit surrounded by a single casing.

Abstract: A frequency conversion apparatus has a high-frequency amplifier for amplifying an input high-frequency signal, a mixer for mixing the output signal of the high-frequency amplifier with a local oscillation signal, a filter for restricting the band of the output signal of the mixer to permit passage of only components within a predetermined band, and a variable filter provided between the high-frequency amplifier and the mixer and having a controllable cut-off frequency. With this configuration, it is possible to reduce back talk at low cost without inviting variation of input return loss characteristics.

Abstract: A double conversion-type electronic tuner includes a first IF signal amplifying circuit having a field-effect transistor that amplifies an intermediate frequency signal at a predetermined gain, and input the resultant signal to a down-converter via a band-pass filter. The electronic tuner further includes a temperature compensating section formed by a serial circuit composed of an NTC-thermistor provided between the first IF signal amplifying circuit and a coupling capacitor of the band-pass filter. In this structure, when the temperature is changed, the degree of coupling between the circuits is varied to compensate for a variation of the gain caused by a change in temperature. Moreover, the characteristic of a capacitor forming a parallel resonant circuit in the band-pass filter is also varied by a change in temperature, and the matching loss is reduced.

Abstract: An up-converter section and a down-converter section are contained in separate respective chassis. The up-converter section and the down-converter section are linked by an IF link section having a coaxial shielding structure. As such, a high-quality Up/Down tuner can be provided which is able to reduce the mutual influence of up-converter and down-converter local oscillator circuits and the entry of external noise, without increasing the size of the Up/Down tuner.

Abstract: A tuner circuit includes a first IF signal generating a first oscillation signal, a local oscillator circuit outputting a local oscillator signal, a mixing circuit mixing the first IF signal and the oscillation signal to generate a second IF signal, and a first substrate on which at least the local oscillator signal is formed. The local oscillator circuit includes an oscillation circuit and a coaxial resonator connected to the oscillation circuit for correcting the influence of change in oscillation frequency owing to moisture and secular change. The coaxial resonator includes an impedance variable trimmer portion for adjusting the oscillation frequency, a central conductor provided at a fixed position with respect to the first substrate, and an insulator for providing insulation between the impedance variable trimmer and the central conductor. The impedance variable trimmer portion and the central conductor are adhered to one another via the insulator after adjusting is completed.

Abstract: A tuner circuit is basically composed of: a series of a low-band coil and a high-band coil disposed on the signal side; a series of a low-band coil and a high-band coil disposed on the earth side; and a switching diode disposed between a junction of the low-band coil and high-band coil on the signal side and another junction of the low-band coil and high-band coil on the earth side. Further, the junction of the low-band coil and high-band coil on the signal side is connected to a band switching terminal via a first bias resistor while an input side terminal of the low-band coil on the signal side is connected with a second bias resistor.