Nihon Dempa Kogyo Co., Ltd.

Nihon Dempa Kogyo, Ltd.

Dsp Technology Associates, Inc.

Tsukasa Kobata

Kazuo Akaike

Nobuo Tsukamoto

Naoki Onishi

Tsuyoshi Shiobara

Shunichi Wakamatsu

Tomoya Yorita

Shinichi Sato

Hiroki Kimura

Yasuo Kitayama

Mitsuaki Koyama

Kaoru Kobayashi

In an oscillator device that outputs a frequency signal based on an oscillation frequency of a crystal resonator and a frequency setting value, a frequency difference detector that obtains a difference value corresponding to a frequency difference between the output frequency of the oscillator device and an external clock signal and a temperature detector are disposed. An aging coefficient and a temperature characteristic coefficient are obtained based on a secular change of the difference value obtained in the frequency difference detector and a secular change of the detected temperature during a period where the external clock signal is obtained. Furthermore, a frequency correction value is calculated using the aging coefficient and the temperature characteristic coefficient during a holdover period, and the frequency correction value is added to the frequency setting value.

Oscillator device

A PLL device includes a voltage control oscillation unit, an analog/digital converter, a quadrature demodulation unit, a comparison signal output unit, a phase difference detection unit, a loop filter, and a digital/analog converter. The quadrature demodulation unit quadrature-demodulates the digital feedback signal to obtain an in-phase component (I component) and a quadrature-phase component (Q component). The comparison signal has a set frequency of the output signal when the feedback signal is the output signal and has a frequency obtained by dividing the set frequency by the dividing number when the feedback signal is the frequency division signal. The phase difference detection unit obtains a phase difference between the digital feedback signal and the digital comparison signal based on the I component and the Q component of the digital feedback signal and the I component and an Q component of a comparison signal.

PLL device

In an OCXO, which outputs an oscillation frequency by oscillating a crystal resonator, a correspondence relationship between an oscillation frequency and an elapsed time at a beginning after a start of oscillation of a first crystal resonator is acquired. Based on the acquired result, data after the beginning and corresponding to a correspondence relationship between an accumulated elapsed time of the oscillation and the oscillation frequency after the start of the oscillation is obtained. Based on the accumulated elapsed time of the oscillation and this data, a frequency setting value is corrected. While an output frequency of the first crystal resonator fluctuates in association with the elapsed time, the output frequency is corrected by the frequency correction value corresponding to the accumulated elapsed time, thereby stabilizing the oscillation frequency.

Oscillation device and method for manufacturing the oscillation device

An oscillator detects a temperature of an atmosphere where a crystal resonator for an oscillation output is placed using a temperature detector to stabilize the temperature by controlling a temperature of a heater based on a temperature detection value. The device includes a buffer amplifier interposed in a signal path of a control signal generated based on the temperature detection value, a heater disposed such that a collector and an emitter position between a power source unit and a ground and constituted of a transistor having a base connected to an output port of the buffer amplifier, and a first differential amplifier disposed to adjust a gain of the buffer amplifier to cancel voltage fluctuation of the power source unit and amplifying a difference between a voltage corresponding to the supply voltage and a preliminarily set voltage to input to a gain adjustment port of the buffer amplifier.

Oscillator for detecting temperature of atmosphere

A temperature control device includes a temperature detector, a difference operation unit, a controller, a saturation processing circuit unit, a rewritable storage unit, and a conversion unit. The difference operation unit operates a digital value corresponding to a difference value between a detected temperature value and a target temperature. The controller calculates a manipulated variable using the digital value operated by the difference operation unit. The saturation processing circuit unit includes a digital circuit to limit an output value of the controller to a pre-set upper limit value. The rewritable storage unit stores the upper limit value read from a storage area of the rewritable storage unit and input into the saturation processing circuit unit. The conversion unit converts the output value of the saturation processing circuit unit into an analog signal to output the converted value as a control command value to the heater.

Temperature control device and oscillator

An oscillator configured to obtain a frequency output corresponding to a frequency setting value includes: an oscillation circuit portion that receives the frequency setting value; a setting value output portion that outputs a digital value for designating the frequency setting value; an interpolation circuit portion that performs interpolation for a digital value of lower-order bits out of the digital value output from the setting value output portion; and an adder that adds an output of the interpolation circuit portion and a digital value of higher-order bits out of the digital value output from the setting value output portion, wherein a signal output from the interpolation circuit portion is sequential data having first and second values different from each other, and output counts of the first and second values are determined based on a ratio corresponding to the digital value of the lower-order bits.

Oscillator

An oscillation device is provided. The oscillation device includes: a main circuit portion, a heating unit, first and second crystal units, first and second oscillator circuits, a frequency difference detector, a first addition unit, an integration circuit unit, a circuit unit configured to control an electric power to be supplied to the heating unit, a compensation value obtaining unit, and a second addition unit. The compensation value obtaining unit is configured to obtain a frequency compensation value for compensating an output frequency of the main circuit portion based on an integrated value output from the integration circuit unit, and based on a change in the clock signal due to a difference between the temperature of the atmosphere and the temperature setting value of the heating unit. The second addition unit is configured to add the frequency compensation value to a frequency setting value.

Oscillation device

Electronic equipment according to the present disclosure includes a writable non-volatile memory, a plurality of volatile memories, and a sequencer. The writable non-volatile memory stores an operation parameter group required to operate the electronic equipment. Respective addresses are assigned to the plurality of volatile memories. The plurality of volatile memories includes a specified volatile memory. The specified volatile memory stores a part of the operation parameters among the operation parameter group. The specified volatile memory is accessible by inputting an Enable signal. The sequencer can read and write the non-volatile memory when the Enable signal allows an operation parameter stored in the volatile memory to be written to the non-volatile memory.

Electronic equipment

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 fand f, and oscillation frequencies of the oscillation outputs at a reference temperature are set to fand, respectively, {(f&#x2212;f)/f}&#x2212;{(f&#x2212;f)/f} 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.

Quartz-crystal controlled oscillator

An oscillator includes a nominal frequency output unit, a frequency adjustment amount output unit, a gain output unit, a multiplier, and an adder. The nominal frequency output unit is configured to output a first digital value corresponding to the nominal frequency. The frequency adjustment amount output unit is configured to output a second digital value corresponding to a rate of frequency in order to set a frequency adjustment amount with respect to the nominal frequency using the rate of frequency. The gain output unit is configured to output a third digital value corresponding to a gain to be multiplied by the second digital value. The multiplier is configured to multiply the second digital value by the third digital value, thus outputting a fourth digital value. The adder adds the first digital value and the fourth digital value to output the added result as a setting signal of frequency.

Oscillator with frequency adjustment

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.

Frequency synthesizer

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.

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.

Signal generator

Provided is a frequency synthesizer capable of fine setting over a wide band and having a wide frequency pull-in range. A sine wave signal of an output frequency of a voltage controlled oscillating part is quadrature-detected, and in a PLL utilizing a vector rotating at a frequency (velocity) equal to a difference from a frequency of a frequency signal used for the detection, a frequency pull-in means integrates a first constant for increasing the output frequency as a pull-in voltage when a control voltage from the PLL to the voltage controlled oscillating part is larger than a prescribed set range, and integrates a second constant for decreasing the output frequency as the pull-in voltage when the control voltage is smaller than the set range. Then, an adding means adds the control voltage from the PLL and the pull-in voltage from the frequency pull-in means to output an addition result to the voltage controlled oscillating part.

The provision of a technique capable of determining a state where PLL control does not operate normally instantly or in advance in a frequency synthesizer that frequency-divides, A/D converts, and quadranture-detects a frequency signal from a voltage controlled oscillating unit, and extracts a rotation vector rotating at a frequency difference between the frequency signal used for the detection and the A/D converted frequency signal, and integrates a difference between a frequency of the above rotation vector and a set frequency to set an integration result as a control voltage to the voltage controlled oscillating unit. The control voltage to be input to the voltage controlled oscillating unit is monitored, and it is determined whether or not a level of the monitored control voltage deviates from a set range determined in advance, and an unlock detection signal is output. In a structure in which the rotation vector is multiplied by a reverse rotation vector reversely rotating at a frequency determined in rough increments according to the set frequency to reduce a velocity of the rotation vector, a determination result whether or not a length of the rotation vector whose velocity is reduced (a scalar quantity) or a correction signal for gain control deviates from a range set in advance is further considered.

Growing community of inventors

Sayama, Japan

Tsukasa Kobata