Abstract: The present invention has for its object to provide a piezoelectric oscillator that has improved secular variation characteristics and excels in suppressing undesired resonance.

Abstract: A direct sequence spread spectrum system consisting of modulator and demodulator wherein the spreading sequence with zero correlation zone properties, and the despreading consists of multiplying the received signal with the same spreading sequence, followed by a low pass filter, decoder and deinterleaver. The bit rate of the spreading sequence for each user is normally much higher than the input encoded data bit rate, and therefore it spreads the system spectrum.

Abstract: In comb-form spectrum communication systems using repeated complementary sequence modulation, a transmitting signal is constituted by assigning one set of N auto-complementary sequences to each user, where N is an integer equal to or higher than 2, and by transforming the N sequences to N repeated signals which have comb-form spectra without overlapping in frequency with one another with a method of repeating each sequence of the set of auto-complementary sequences a plurality of times, and by assigning the N complementary sequences with auto-complementary sequence characteristics to the N comb-form spectra. Thus, the near-far problem is solved by making the cross-correlation between a signal input to a user's station but addressed to another station and the user's reference code sequence, zero.

Abstract: In the high-frequency piezoelectric oscillator, capacitors C1, C2 as a part of a load capacitor are connected between a base of a transistor TR1 and the ground. The connection point of the capacitors C1, C2 is connected to an emitter of the transistor TR1, and is grounded via an emitter resistor R1. A base bias circuit consisting of resistors RB1 and RB2 is connected to the base of the transistor TR1. A piezoelectric vibrator, an inductor, and a resistor are connected in parallel, and connected between the base of the transistor TR1. A capacitor is connected to the parallel circuit and grounded. A collector of the transistor and a power supply line are connected together.

Abstract: The object of the present invention is to provide an angular velocity sensor that uses Coriolis force with a flatly supported double tuning fork structure that uses an in-plane asymmetrical flexural secondary mode. A large support area is used to provide a high-precision angular velocity sensor with superior resistance to vibration and impact. A double tuning fork gyro-sensor is formed integrally from: two arms; a driver electrode formed on the arms; and a double tuning fork supporting the ends of the arms. Also included are: a detection module connected to the double tuning fork support section; a detection electrode formed on the detection module; and a support securing section for the detection module. When there is rotation, the Coriolis force acting on the arms is transferred to the detection module by way of the double tuning fork support section so that an in-plane asymmetrical flexural secondary vibration takes place.

Abstract: A wavelength division element includes a first filter and a second filter. The first filter has incident angle-to-transmission wavelength characteristics and separates multiplexed lights in a plurality of wavelength bands into first lights that are in a first wavelength band and first reflected lights. The first filter allows the first lights to pass through in a first direction and reflects the first reflected lights in a second direction. The second filter is located in the second direction and separates the first reflected lights into second lights that are in a second wavelength band and second reflected lights. The second filter allows the second lights to pass through in a third direction and reflects the second reflected lights in a fourth direction.

Abstract: The present invention provides an angular velocity sensor that uses Coriolis force with a flatly supported double-ended tuning fork structure that uses an in-plane asymmetrical flexural secondary mode. A large support area is used to provide a high-precision angular velocity sensor with superior resistance to vibration and impact. A double-ended tuning fork gyro-sensor is formed integrally from: two arms; a driver electrode formed on the arms; and a double-ended tuning fork supporting the ends of the arms. Also included are: a detection module connected to the double-ended tuning fork support section; a detection electrode formed on the detection module; and a support securing section for the detection module. When there is rotation, the Coriolis force acting on the arms is transferred to the detection module by way of the double tuning fork support section so that an in-plane asymmetrical flexural secondary vibration takes place.

Abstract: [Object of the invention] To provide designing means that prevents deterioration through thermal aging of an electronic part used in high-stability piezoelectric oscillators and the like when the high end of the usage temperature is 85 deg C. [Means for solving the problem] In a high-stability piezoelectric oscillator equipped with: a first isothermic oven housing a piezoelectric vibrator and an electronic part; a second isothermic oven; a case; and the like, a high-stability piezoelectric oscillator wherein a temperature of the first isothermic oven is set to be lower than a temperature of a second isothermic oven using a Peltier element or the like.

Abstract: As a 1/2 wave plate constituted by laminating two wave plates, a wave plate where temperature dependence of a phase difference is reduced is provided. In a wave plate constituted by laminating a first wave plate having a phase difference &tgr;1 (deg.) and an optical axis azimuth &thgr;1 (deg.), and a second wave plate having a phase difference &tgr;2 (deg.) and an optical axis azimuth &thgr;2 (deg.), the phase difference &tgr;1 (deg.) of the first wave plate and the phase difference &tgr;2 (deg.) of the second wave plate are set to 360n+180 (n=0, 1, 2 . . . ), and an angle formed by polarization planes of incident light and emitted light is &thgr; (deg.). In this case, the first wave plate and the second wave plate are laminated so as to satisfy &thgr;1=(90+&thgr;/2)/2 and &thgr;2=&thgr;1+90&thgr;/2.

Abstract: In an inverter oscillation circuit an output terminal 2 of an inverter 1 with its input and output interconnected via a high resistance R1 is grounded via a series connection of a capacitor C1 and parallel tuning circuit composed of a capacitor C2 and an inductor L1 connected in parallel, and the connection point of this series connection is grounded via a parallel circuit of diodes D1 and D2 connected in opposite polarities. The connection point of the series connection is connected to an input terminal 3 of the inverter 1 via series-connected capacitors C3 and C4, and the connection point of this series connection is grounded via a piezoelectric vibrator Xtal and a frequency adjusting capacitor C7. The inverter oscillation circuit is configured to provide its output via a series circuit composed of a resistor R2 and a capacitor C6.

Abstract: In a piezoelectric oscillator a non-inverted output terminal (3) of an ECL circuit (10) is grounded via a capacitor (C3) and is connected to a non-inverting input terminal (5) of the ECL circuit (10) via a series connection of capacitors (C4) and (C5). The non-inverting input (5) is connected via a resistor R1 to an an inverting input terminal (4) of the ECL circuit (10) and is grounded via a capacitor (C2). The connection point of the series connection of the capacitors (C4) and (C5) is grounded via a crystal oscillator (X'tal) and a frequency control capacitor (C1). The output from the ECL circuit (10) is provided at its inverted output terminal 2.

Abstract: Piezo oscillators having a quick start-up circuit, which applies a start-up quickening voltage to the piezo resonator only for a predetermined length of time after the application of power supply voltage, added to a piezo oscillating circuit. The start-up time taken for the piezo oscillators to reach the steady-estate oscillation from the non-oscillating state can be significantly shortened. The phase noise characteristics and frequency stability characteristics are not affected, since the start-up quickening voltage is removed after the predetermined length of time.

Abstract: In the case where an ultraminiature piezoelectric substrate, which has a resonating portion formed by making a concavity by etching in the surface of the piezoelectric substrate made of an anisotropic crystal material, is mass-produced by batch operation using a large-area piezoelectric substrate wafer, an annular portion surrounding each concavity is formed sufficiently thick to prevent cracking from occurring when the wafer is severed.

Abstract: Disclosed is a piezoelectric resonator that has a piezoelectric plate that has formed thereon a pair of main electrodes and has formed thereon a second electrode surrounding the peripheral edge of the main electrode with a gap being provided between the second electrode and a peripheral edge of the main electrode. The material of the main electrode and the material of the second electrode are differentiated from each other. As the material of the second electrode there is used a material the density of that is lower than the material of the main electrode. With this construction, there is obtained means for suppressing the occurrence of spurious due to an inharmonic mode generating in the high frequency piezoelectric resonator.

Abstract: The invention provides a temperature compensated crystal oscillator that can obtain a large variable range and that can obtain high temperature stability. This temperature compensation system employs a configuration comprising a oscillation circuit 12 including a crystal vibrator 11 having a piezoelectric element excited in a given frequency and an oscillation amplifier that excites the piezoelectric element by flowing a current to the piezoelectric element, a vibrator current control circuit 13 that controls the current of the crystal vibrator, a temperature compensation voltage generation circuit 15 that compensates for temperature characteristics of the crystal vibrator 11, and an external variable capacitance diode 17 that changes the oscillation frequency of the oscillation circuit 12 using an external variable voltage controller 16. The vibrator current control circuit 13 comprises a variable capacitance diode 14 that controls the vibrator current, and capacitors 1 to 3.

Abstract: In the high-frequency piezoelectric oscillator, capacitors C1, C2 as a part of a load capacitor are connected between a base of a transistor TR1 and the ground. The connection point of the capacitors C1, C2 is connected to an emitter of the transistor TR1, and is grounded via an emitter resistor R1. A base bias circuit consisting of resistors RB1 and RB2 is connected to the base of the transistor TR1. A piezoelectric vibrator, an inductor, and a resistor are connected in parallel, and connected between the base of the transistor TR1. A capacitor is connected to the parallel circuit and grounded. A collector of the transistor and a power supply line are connected together.

Abstract: A piezoelectric oscillator is disclosed which falls under the category of an oscillator including a piezoelectric resonator, an amplifier, and a variable-capacitance element. The variable-capacitance element is a MOS construction type capacitance element, one terminal of that is fixed at a V voltage, and the other terminal of that is applied with a control voltage falling within a range whose intermediate value is the V voltage. As a result of this, a piezoelectric oscillator is realized which can vary its frequency over a wide range even without use of a minus power supply.

Abstract: The present invention provides a piezoelectric vibration gyro-sensor utilizing Coriolis force that includes a tuning fork type vibrator in which two rectangular-columnar arms and a base to support the lower end of the arms are integrated; drive electrodes formed on two rectangular-columnar arms; and IDT electrodes of a surface acoustic wave element formed on two arms. Two pairs of the drive electrodes are provided on each rectangular-columnar arm, in which each of the pairs of drive electrodes face each other, and each pair of the drive electrodes are arranged in parallel on the rectangular-columnar arm at a given distance. The IDT electrodes of the surface acoustic wave element are provided between the drive electrodes at the lower end of the rectangular-columnar arms.

Abstract: [Object of the invention] To provide designing means that prevents deterioration through thermal aging of an electronic part used in high-stability piezoelectric oscillators and the like when the high end of the usage temperature is 85 deg C.

Abstract: In an AT-cut quartz resonator having excitation electrodes formed on two principal surfaces of an AT-cut quartz substrate, the two electrodes are displaced a predetermined amount apart in a direction orthogonal to the X-axis direction so that a frequency deviation in a temperature range of from −10° C. to 50° C. is less than ±2.5 ppm. Further, in an AT-cut quartz resonator in which vertically opposed electrodes on both principal surfaces of a quartz substrate are slightly displaced apart in opposite directions along the Z′ axis of quartz crystal, a balancing load is formed on a piezoelectric substrate on the side opposite to the direction of displacement of the electrodes.