Abstract: It is the object to minimize a magnetic influence, on the outside, of a semiconductor chip which is formed on a substrate includes inductor conductors. A semiconductor chip 2 including inductor conductors is mounted on a substrate 1 and a plurality of through holes 8 are formed in the area on the outside of the mounting position. Shielding members 4 are formed on the chip mounting side and the opposite side of the substrate 1 and in the through holes 8 so as to cover the semiconductor chip 2 with the shielding members 4 from both sides of the substrate 1. Therefore, magnetic fluxes from a circuit formed on the semiconductor chip 2 do not leak out from the shielding members 4, but circulate inside the shielding members 4.

Abstract: A tuning circuit which has a wide tuning bandwidth. The tuning bandwidth of the tuning frequency can be easily changed. The tuning circuit 1 is composed of two cascade-connected tuning amplifier sections 2 and 3. Each of the sections 2 and 3 is provided with cascade-connected phase-shifting circuits 10C and 30C, a voltage dividing circuit 60, and an adding circuit composed of a feedback resistor 70 and an input resistor 74. Prescribed tuning operation is performed by shifting the phase of a prescribed frequency by 360.degree. by means of the phase shifting circuits 10C and 30C and setting the open loop gain of a feedback loop at less than 1 when the output of the voltage dividing circuit 60 is feedback. The resistance ratio between the feedback resistor 70 and input resistor 74 of each tuning amplifier section is adjusted in order that the maximum damping of each tuning amplifier section becomes smaller and the tuning bandwidth of each amplifier section becomes wider.

Abstract: A tuning circuit which has a wide tuning bandwidth. The tuning bandwidth or the tuning frequency can be easily changed. The tuning circuit 1 is imposed of two cascade-connected tuning amplifier sections 2 and 3. Each of the sections 2 and 3 is provided with cascade-connected phase-shifting circuits 10C and 30C, a non-inverting circuit 50, a voltage dividing circuit 160, and an adding circuit composed of a feedback resistor 70 and an input resistor 74. Prescribed tuning operation is performed by shifting the prescribed frequency 360.degree. by means of the phase shifting circuits 10C and 30C and setting the open loop gain of a feedback loop at less than 1 when the output of the voltage dividing circuit 160 is feedback. The resistance ratio between the feedback resistor 70 and the input resistor 74 of each section 2, 3 is adjusted so that the maximum damping of each section 2, 3 may become smaller and the tuning bandwidth of each section 2, 3 becomes wider.

Abstract: A tuning amplifier 1 is provided with two cascade connected phase shifting circuits 10C and 30C and an adding circuit composed of a feedback resistor 70 and input resistor 74. The circuit 10C is constituted of an operational amplifier 12, a resistor 18 one end of which is connected to the inverting input terminal of the amplifier 18, a resistor 20 connected between the inverting input terminal and the output terminal of the amplifier 12, a series circuit which comprises a capacitor 14 and a variable resistor 16 and one end of which is connected to the other end of the resistor 18. The fluctuation of the output amplitude of the circuit 10C is suppressed when the tuning frequency of the circuit 10C is changed because the resistance of the resistors 18 and 20 are equal to each other.

Abstract: A variable inductance element comprising an inductor conductor 10 having a predetermined shape formed on an insulation layer 40 on the surface of a semiconductor substrate 42, switches 16 and 24 for shorting portions of the inductor conductor 10, and input/output terminals 12 and 14 provided at the respective ends of the inductor conductor 10. When switches 16 and/or 24 is in the on state, the function as an inductor having a smaller inductance than the overall inductor conductor 10 is obtained. The inductance of this variable inductance element can be changed by external control, while manufacturing is easy and formation in a unitized manner with an integrated circuit or other semiconductor device is enabled.

Abstract: A laminate type LC element includes a laminate defined by a plurality of stacked insulating layers. A first sheet-like conductor is formed between each pair of adjacent insulating layers to continuously wind and extend from between the pair of adjacent insulating layers to between another pair of adjacent insulating layers, the first conductor forming a coil having a preselected number of turns. A second sheet-like conductor is formed between each pair of adjacent insulating layers to continuously wind and extend from between the pair of adjacent insulating layers to between another adjacent pair of adjacent insulating layers, the second conductor being disposed in the face-to-face relationship relative to the first conductor through the insulating layers. The LC element has an increased capacitance and can reliably remove any external noise.

Abstract: The invention provides a novel apparatus for manufacturing electronic parts each incorporating a plurality of lead wires fully wrapped with conductive foil like noise filters for example. A turn table is intermittently shifted from the first work station to the seventh work station in the state in which an individual-unit lead-wire member is retained by a holding unit on the turn table. A predetermined lead wire is folded by respective work stations, whereas the remaining lead wires are adhered with conductive foil tapes via spot-welding process, and then these lead wires are fully wrapped with conductive foil tapes. Next, the predetermined lead wire is restored to the initial posture, and then all the lead wires are fully wrapped with insulation tapes. In this way, all the lead wires are properly processed so that they can be integrated in perfect alignment with constant pitches.