Abstract: An ultra-low noise crystal oscillator uses two crystal unit; an oscillation element of an oscillation circuit section and a crystal filter of a subsequent filter section. A Butler circuit in which the capacitors (C1, C2) and the inductor (L) connected in series is connected in parallel to the oscillator circuit section. This is the crystal oscillator that simplifies the manufacturing process, improves the manufacturing quality, and has good floor noise characteristics.

Abstract: An ultra-low noise crystal oscillator uses two crystal unit; an oscillation element of an oscillation circuit section and a crystal filter of a subsequent filter section. A Butler circuit in which the capacitors (C1, C2) and the inductor (L) connected in series is connected in parallel to the oscillator circuit section. This is the crystal oscillator that simplifies the manufacturing process, improves the manufacturing quality, and has good floor noise characteristics.

Abstract: A circuit for protecting a DUT is disposed in parallel with a DUT which is supplied with current via wirings and switchable between conducting and non-conducting state. The circuit is switchable between conducting and non-conducing state and switched from non-conducting state to conducting state as the DUT is switched from conducting state to non-conducting state.

Abstract: A crystal oscillator in which a temperature characteristic of an oscillation frequency is improved to omit a measurement operation of the temperature characteristic of the oscillator, and manufacturing is facilitated to reduce a manufacturing time. In the crystal oscillator, a power voltage is applied to a collector of a transistor via series connection of an inductor for resonance and a resistance, a crystal unit is disposed in a loop which returns to an emitter of the transistor from a point between the inductor L4 and the resistance, and further, in the loop, a first parallel circuit in which a stationary capacitor having a negative temperature coefficient and a stationary capacitor having a zero temperature coefficient are connected in parallel with each other is inserted between an oscillation output taking point and the collector.

Abstract: By allowing an electrical conduction between a probe and an electrode by a fritting phenomenon before inspection, simplification of circuit configuration and shortening of inspection time is achieved. A fritting circuit is formed in a probe card of an inspection apparatus for each probe pair consisting of two probes. A capacitor is connected to each fritting circuit. Each fritting circuit is connected in parallel to a power supply circuit having a charging power supply. Each capacitor is charged at one time by the power supply circuit. The probe pair is brought into contact with an electrode of a wafer, and a high-voltage is applied to the probe pair by a power charged in the capacitor, thereby achieving an electrical connection between each probe and the electrode by a fritting phenomenon. Then, an inspection of electrical characteristics is performed by using an electric inspection signal transmitted to each probe.

Abstract: A harmonic oscillator comprises a transmission line resonator in which an oscillation frequency depends on an electrical length of a transmission line and both ends of the transmission line are electrical open ends; an active element for oscillation as a negative resistance connecting to the transmission line resonator; an output line connected to a midpoint portion of the transmission line resonator; and electrical and/or physical suppressing means for suppressing a voltage displacement distribution of second harmonic among the even-order harmonics. The suppressing means is provided at a position which is at least a minimum voltage displacement portion for the second harmonic between the midpoint portion and either ends of the transmission line resonator.

Abstract: By allowing an electrical conduction between a probe and an electrode by a fritting phenomenon before inspection, simplification of circuit configuration and shortening of inspection time is achieved. A fritting circuit is formed in a probe card of an inspection apparatus for each probe pair consisting of two probes. A capacitor is connected to each fritting circuit. Each fritting circuit is connected in parallel to a power supply circuit having a charging power supply. Each capacitor is charged at one time by the power supply circuit. The probe pair is brought into contact with an electrode of a wafer, and a high-voltage is applied to the probe pair by a power charged in the capacitor, thereby achieving an electrical connection between each probe and the electrode by a fritting phenomenon. Then, an inspection of electrical characteristics is performed by using an electric inspection signal transmitted to each probe.

Abstract: A high-frequency filter includes a substrate; a ground conductor disposed on one main surface of the substrate and having an opening; a center conductor making up a coplanar line resonator together with the substrate and the ground conductor; and an input line and an output line each of which has a microstrip line structure and is disposed on the other main surface of the substrate to electromagnetically couple with the center conductor. At least one of the input line and the output line has a closed loop line portion surrounding a corresponding end of the center conductor and crossing the center conductor transversely through the substrate. On the other main surface of the substrate, a stub overlapping with the center conductor is arranged from a transverse position where the closed loop line portion crosses the center conductor.

Abstract: In a balun for mutually converting an unbalanced line for unbalanced input/output and a balanced line for balanced input/output, the unbalanced line and the balanced line are microstrip lines including a signal line arranged on one main surface of a substrate and a ground conductor arranged on the other main surface of the substrate. The balun further includes a slot line formed by a aperture line arranged in the ground conductor in the other main surface. The microstrip line as the unbalanced line includes one end portion used as an input/output end and the other end portion that traverses the slot line, electromagnetically couples to the slot line, and functions as an electric short-circuited end. The central portion of the microstrip line as the balanced line traverses the slot line and electromagnetically couples to the slot line. Both ends of this microstrip line serves as the input/output ends.

Abstract: There is disclosed a crystal oscillator in which when a base ground type crystal oscillation circuit is used, a temperature characteristic of an oscillation frequency is improved to omit a measurement operation of the temperature characteristic of the oscillator, and manufacturing is facilitated to reduce a manufacturing time.

Abstract: A circuit for protecting a DUT is disposed in parallel with a DUT which is supplied with current via wirings and switchable between conducting and non-conducting state. The circuit is switchable between conducting and non-conducing state and switched from non-conducting state to conducting state as the DUT is switched from conducting state to non-conducting state.

Abstract: A harmonic oscillator comprises a transmission line resonator in which an oscillation frequency depends on an electrical length of a transmission line and both ends of the transmission line are electrical open ends; an active element for oscillation as a negative resistance connecting to the transmission line resonator; an output line connected to a midpoint portion of the transmission line resonator; and electrical and/or physical suppressing means for suppressing a voltage displacement distribution of second harmonic among the even-order harmonics. The suppressing means is provided at a position which is at least a minimum voltage displacement portion for the second harmonic between the midpoint portion and either ends of the transmission line resonator.

Abstract: In a balun for mutually converting an unbalanced line for unbalanced input/output and a balanced line for balanced input/output, the unbalanced line and the balanced line are microstrip lines including a signal line arranged on one main surface of a substrate and a ground conductor arranged on the other main surface of the substrate. The balun further includes a slot line formed by a aperture line arranged in the ground conductor in the other main surface. The microstrip line as the unbalanced line includes one end portion used as an input/output end and the other end portion that traverses the slot line, electromagnetically couples to the slot line, and functions as an electric short-circuited end. The central portion of the microstrip line as the balanced line traverses the slot line and electromagnetically couples to the slot line. Both ends of this microstrip line serves as the input/output ends.

Abstract: A high-frequency filter includes a substrate; a ground conductor disposed on one main surface of the substrate and having an opening; a center conductor making up a coplanar line resonator together with the substrate and the ground conductor; and an input line and an output line each of which has a microstrip line structure and is disposed on the other main surface of the substrate to electromagnetically couple with the center conductor. At least one of the input line and the output line has a closed loop line portion surrounding a corresponding end of the center conductor and crossing the center conductor transversely through the substrate. On the other main surface of the substrate, a stub overlapping with the center conductor is arranged from a transverse position where the closed loop line portion crosses the center conductor.

Abstract: This is a crystal oscillator comprising a heater whose heater line is multiplied and a control unit for controlling the heater.