Abstract: In forming a frequency synthesizer by using PLL using processing of digital signals, an A/D converting unit is not required. By the integration of a digital value that depends on a set frequency, a saw-tooth wave serving as a phase signal is generated. A frequency signal output from a voltage-controlled oscillator is input via a frequency divider to an edge detecting unit, which then detects a rising edge or a falling edge of the frequency signal to generate a rectangular-wave signal that depends on a frequency of the frequency signal. Then, a latched circuit latches a value of the saw-tooth wave in response to the rectangular-wave signal, and this value is integrated in a loop filter and the resultant is used as a control voltage of the voltage-controlled oscillator.

Abstract: There is provided a frequency synthesizer capable of improving phase noise. A sinusoidal signal with a frequency set by a frequency setting part is output as a digital signal from a set signal output part, and the digital signal is D/A-converted. A difference between a sinusoidal signal with a frequency corresponding to an output frequency of a voltage controlled oscillating part and a sinusoidal signal output from a D/A converting part is amplified by a differential amplifier, and an amplified signal is input via an A/D converting part to a means for extracting a phase difference between the aforesaid sinusoidal signals. A voltage corresponding to a signal being the result of integration of the phase difference is input as a control voltage to the voltage controlled oscillating part. Then, a gain of the differential amplifier is set larger than a maximum value of phase noise degradation of the A/D converting part, whereby the phase noise degradation of the A/D converting part is cancelled.

Abstract: A surface mount device in which a pin adapter that is integrally formed with a plurality of pins connects a base board and a main board is provided to enable an automatic mounting, to enable a reflow soldering, to increase the flexibility of design, and to satisfy requirements of customers. In the surface mount device, a pin adapter 5 that is formed integrally with a plurality of pins 6 is placed on a base board 1, the base board 1 and the main board 2 are connected by inserting the tips of the pins 6 into the corresponding locations of the main board 2, the leg portions of the pin adapter 5 are folded toward inside, and opening sections 52 are formed at the leg portions.

Abstract: To perform, in an oscillation device compensating an output frequency based on a detection result of ambient temperature, temperature compensation of the output frequency with high accuracy. First and second quartz-crystal oscillators are structured by using a common quartz-crystal piece, and when oscillation outputs of first and second oscillation circuits respectively connected to these quartz-crystal oscillators are set to f1, f2, and oscillation frequencies of the first and the second oscillation circuits at a reference temperature are set to f1r, f2r, respectively, a frequency difference being a difference between a value corresponding to a difference between f1 and f1r and a value corresponding to a difference between f2 and f2r is treated as a temperature at that time. Further, based on the frequency difference, a frequency compensation value is determined through polynomial approximation.

Abstract: An oscillation device capable of highly accurate temperature compensation of an output frequency is provided. The oscillation device includes: first and second oscillator circuits oscillating first and second quartz-crystal resonators with overtones respectively; a frequency difference detecting part finding a value corresponding to a difference value between values corresponding to differences between f1 and f1r and between f2 and f2r, where f1 and f2 are oscillation frequencies of the first and second oscillator circuits, and f1r and f2r are oscillation frequencies of the first and second oscillator circuits at a reference temperature; and a correction value obtaining part which, based on the value corresponding to the difference value and a relation between the value corresponding to the difference value and a frequency correction value of the oscillation frequency f1, obtains the frequency correction value of f1, wherein the output frequency is corrected based on the found frequency correction value.

Abstract: There is provided a voltage controlled oscillator that is compact and can be manufactured at low cost. The voltage controlled oscillator is structured to include: a resonance part including a variable capacitance element and an inductance element, the variable capacitance element having a capacitance that varies according to a control voltage for frequency control input from an external part, and a series resonant frequency of the resonance part being adjusted according to the capacitance; an amplifying part amplifying a frequency signal from the resonance part; and a feedback part including a capacitance element for feedback and feeding the frequency signal amplified by the amplifying part back to the resonance part to form an oscillation loop together with the amplifying part and the resonance part, wherein the amplifying part is provided in an integrated circuit chip, and the resonance part and the capacitance element for feedback are formed as circuit components separate from the integrated circuit chip.

Abstract: Provided is an oscillation device capable of obtaining a stable oscillation frequency by compensating for a change in oscillation frequency caused with an elapse of operating time of a quartz-crystal oscillator. A difference value ?F between a frequency difference between first and second quartz-crystal oscillators after a predetermined period of time has elapsed from a reference time and a frequency difference between the first and second quartz-crystal oscillators at the reference time is determined.

Abstract: There is provided a signal generator outputting an analog frequency signal based on a digital value according to a set frequency, which provides excellent noise characteristics, requires no ROM table corresponding to waveform data, and has a simple configuration. A digital signal having a digital value according to a set frequency is integrated to generate a waveform in a sawtooth shape, a waveform in a triangular wave shape is generated based on the waveform, and this waveform output is differentiated and then D/A converted and integrated. A comparator using, for example, the voltage at a midpoint of the triangular wave as a threshold value is used for the integrated output, and a frequency signal of an objective frequency is obtained from the comparator.

Abstract: To provide a voltage controlled oscillator having small size and capable of obtaining a low phase noise characteristic over a large span of adjustable range of frequency. A quartz crystal having a characteristic (dielectric loss tangent: tan ?) better than that of fluorocarbon resin, LTCC or the like conventionally used as a substrate of a resonance part, and on which a fine pattern of metal film can be formed through a photolithography method, is used as a quartz-crystal substrate, and a conductive line is formed on the quartz-crystal substrate to form an inductance element in the resonance part. Accordingly, since the resonance part having a high Q value can be formed, it is possible to obtain a voltage controlled oscillator having small size and low loss over a wide frequency range.

Abstract: A frequency synthesizer using a PLL has a simple structure and excellent spurious characteristics. A reference frequency signal inputted into a phase comparison unit is generated based on a clock when a zero cross point of a sawtooth wave composed of a digital signal is detected. However, in this case, since the digital values are skipped values, the digital value does not always become zero when its positive/negative sign is inverted. Hence, where the clock signals reading the digital value immediately before and the digital value immediately after the zero cross time when the positive/negative sign is inverted in a region where the digital value gradually changes are P1 and P2 respectively and the clock signal at a timing next to the clock signal P2 is P3, P1 and P3 are used at a ratio corresponding to the ratio between the digital values read by P1 and P2.

Abstract: An atmosphere temperature at which a quartz-crystal oscillator and an oscillation circuit are placed is controlled in high accuracy, and an output frequency with high stability is obtained. If oscillation outputs of first and second quartz-crystal oscillators are set to f1 and f2, and oscillation frequencies of the oscillation outputs at a reference temperature are set to f1r and f2r, respectively, {(f2?f1)/f1}?{(f2r?f1r)/f1r} is calculated by a frequency difference detection unit. A digital value can be obtained by representing this value by 34-bit digital value, corresponding to a temperature. Therefore, this value is treated as a temperature detection value, a difference with a temperature set value is supplied to the loop filter, and the digital value therefrom is converted into a direct-current voltage to control a heater.

Abstract: Provided is a fundamental wave/overtone crystal oscillator to obtain fundamental wave oscillation and overtone oscillation with one crystal unit and to optimize the excitation current depending on the fundamental wave oscillation and the overtone oscillation. The fundamental wave/overtone crystal oscillator includes a crystal unit that oscillates with fundamental waves or with overtones, and an oscillator circuit that amplifies an excitation current from the crystal unit and outputs an oscillatory frequency. A capacitor Cf and a capacitor Co are connected in parallel with the base of a transistor in the oscillator circuit as well as the emitter. A switch is provided so as to connect or disconnect the capacitor Cf with respect to the circuit in response to a switching signal. The switch turns ON when the crystal oscillator oscillates with fundamental waves, and turns OFF when the crystal oscillator oscillates with overtones.

Abstract: In forming a frequency synthesizer by using PLL using processing of digital signals, an A/D converting unit is not required. By the integration of a digital value that depends on a set frequency, a saw-tooth wave serving as a phase signal is generated. A frequency signal output from a voltage-controlled oscillator is input via a frequency divider to an edge detecting unit, which then detects a rising edge or a falling edge of the frequency signal to generate a rectangular-wave signal that depends on a frequency of the frequency signal. Then, a latched circuit latches a value of the saw-tooth wave in response to the rectangular-wave signal, and this value is integrated in a loop filter and the resultant is used as a control voltage of the voltage-controlled oscillator.

Abstract: There is provided a signal generator outputting an analog frequency signal based on a digital value according to a set frequency, which provides excellent noise characteristics, requires no ROM table corresponding to waveform data, and has a simple configuration. A digital signal having a digital value according to a set frequency is integrated to generate a waveform in a sawtooth shape, a waveform in a triangular wave shape is generated based on the waveform, and this waveform output is differentiated and then DIA converted and integrated. A comparator using, for example, the voltage at a midpoint of the triangular wave as a threshold value is used for the integrated output, and a frequency signal of an objective frequency is obtained from the comparator.

Abstract: A frequency synthesizer using a PLL has a simple structure and excellent spurious characteristics. A reference frequency signal inputted into a phase comparison unit is generated based on a clock when a zero cross point of a sawtooth wave composed of a digital signal is detected. However, in this case, since the digital values are skipped values, the digital value does not always become zero when its positive/negative sign is inverted. Hence, where the clock signals reading the digital value immediately before and the to digital value immediately after the zero cross time when the positive/negative sign is inverted in a region where the digital value gradually changes are P1 and P2 respectively and the clock signal at a timing next to the clock signal P2 is P3, P1 and P3 are used at a ratio corresponding to the ratio between the digital values read by P1 and P2.

Abstract: Provided is an oscillation device capable of obtaining a stable oscillation frequency by compensating for a change in oscillation frequency caused with an elapse of operating time of a quartz-crystal oscillator. A difference value ?F between a frequency difference between first and second quartz-crystal oscillators after a predetermined period of time has elapsed from a reference time and a frequency difference between the first and second quartz-crystal oscillators at the reference time is determined.

Abstract: There is provided a temperature compensated piezoelectric oscillator which excels in frequency stability and has a good electronic noise characteristic, and with which a circuit can be structured simply. An auxiliary oscillator unit 21 sharing a crystal substrate 2 with a main oscillator unit 11 outputting a set frequency f0 to an outside is used as a temperature detecting unit 32 detecting a temperature T for obtaining a compensation voltage ?V in a temperature compensated piezoelectric oscillator (TCXO), and electrodes 13, 23 of the main oscillator unit 11 and the auxiliary oscillator unit 21 are provided separately on the crystal substrate 2. For example, a fundamental wave and an overtone are used or a thickness shear vibration and a contour shear vibration are used in the main oscillator unit 11 and the auxiliary oscillator unit 21, respectively.

Abstract: To perform, in an oscillation device compensating an output frequency based on a detection result of ambient temperature, temperature compensation of the output frequency with high accuracy. First and second quartz-crystal oscillators are structured by using a common quartz-crystal piece, and when oscillation outputs of first and second oscillation circuits respectively connected to these quartz-crystal oscillators are set to f1, f2, and oscillation frequencies of the first and the second oscillation circuits at a reference temperature are set to f1r, f2r, respectively, a frequency difference being a difference between a value corresponding to a difference between f1 and f1r and a value corresponding to a difference between f2 and f2r is treated as a temperature at that time. Further, based on the frequency difference, a frequency compensation value is determined through polynomial approximation.

Abstract: An oscillation device capable of highly accurate temperature compensation of an output frequency is provided. The oscillation device includes: first and second oscillator circuits oscillating first and second quartz-crystal resonators with overtones respectively; a frequency difference detecting part finding a value corresponding to a difference value between values corresponding to differences between f1 and f1r and between f2 and f2r, where f1 and f2 are oscillation frequencies of the first and second oscillator circuits, and f1r and f2r are oscillation frequencies of the first and second oscillator circuits at a reference temperature; and a correction value obtaining part which, based on the value corresponding to the difference value and a relation between the value corresponding to the difference value and a frequency correction value of the oscillation frequency f1, obtains the frequency correction value of f1, wherein the output frequency is corrected based on the found frequency correction value.

Abstract: To provide a piezoelectric sensor in which a first electrode for measurement and a second electrode for reference are provided apart from each other on one surface side of a piezoelectric piece and a common electrode is provided on an opposite surface side so as to face the first and second electrodes. A piezoelectric sensor includes: a first electrode for measurement and a second electrode for reference provided apart from each other on one surface side of a piezoelectric piece; a common electrode provided on an opposite surface side of the piezoelectric piece commonly for the first electrode and the second electrode to face the first electrode and the second electrode; and an adsorption layer formed on an area, of the common electrode, to which the first electrode is faced across the piezoelectric piece, to adsorb a substance to be sensed.