WO2017149978A1 - Reference signal generation device and reference signal generation method - Google Patents

Reference signal generation device and reference signal generation method Download PDF

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Publication number
WO2017149978A1
WO2017149978A1 PCT/JP2017/001685 JP2017001685W WO2017149978A1 WO 2017149978 A1 WO2017149978 A1 WO 2017149978A1 JP 2017001685 W JP2017001685 W JP 2017001685W WO 2017149978 A1 WO2017149978 A1 WO 2017149978A1
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WIPO (PCT)
Prior art keywords
output
reference signal
signal
ring oscillator
control unit
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PCT/JP2017/001685
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French (fr)
Japanese (ja)
Inventor
一典 宮原
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古野電気株式会社
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Priority to JP2018502570A priority Critical patent/JPWO2017149978A1/en
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    • G—PHYSICS
    • G04—HOROLOGY
    • G04G—ELECTRONIC TIME-PIECES
    • G04G3/00—Producing timing pulses
    • G—PHYSICS
    • G04—HOROLOGY
    • G04G—ELECTRONIC TIME-PIECES
    • G04G3/00—Producing timing pulses
    • G04G3/02—Circuits for deriving low frequency timing pulses from pulses of higher frequency
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
    • H03K3/353—Generators characterised by the type of circuit or by the means used for producing pulses by the use, as active elements, of field-effect transistors with internal or external positive feedback
    • H03K3/354—Astable circuits
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00—Automatic control of frequency or phase; Synchronisation
    • H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
    • H03L7/08—Details of the phase-locked loop
    • H03L7/099—Details of the phase-locked loop concerning mainly the controlled oscillator of the loop
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION, OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
    • H03L7/00—Automatic control of frequency or phase; Synchronisation
    • H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
    • H03L7/08—Details of the phase-locked loop
    • H03L7/14—Details of the phase-locked loop for assuring constant frequency when supply or correction voltages fail or are interrupted
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M3/00—Conversion of analogue values to or from differential modulation
    • H03M3/02—Delta modulation, i.e. one-bit differential modulation

Definitions

  • the present invention mainly relates to a reference signal generation device including a ring oscillator.
  • a ring oscillator is known as an oscillator that can adjust the frequency of an output signal.
  • a ring oscillator is equipped with a loop-shaped (ring-shaped) circuit, and generates a pulse signal with a predetermined frequency by changing the time (delay time) that it takes for the signal to make a round of the loop-shaped circuit. can do.
  • Patent Document 1 discloses a reference signal generator having such a ring oscillator.
  • the ring oscillator disclosed in Patent Document 1 includes a loop-like circuit having a branch and a plurality of delay elements, and the number of delay elements that pass depends on a path through which a signal passes.
  • the reference signal generator can output a signal having a desired frequency from the ring oscillator by controlling so that a signal passing through a predetermined path is output.
  • the reference signal generator generates a highly accurate frequency or timing signal (reference signal) by synchronizing a signal output from the ring oscillator with a highly accurate reference signal.
  • Patent Document 1 also describes that the reference signal generator performs self-running control.
  • the self-running control is performed when an appropriate reference signal cannot be used, and is a control that generates a highly accurate reference signal without using a reference soot signal.
  • the reference signal generator obtains and stores the temperature variation characteristic of the delay amount of the delay element while an appropriate reference signal is available. Then, when an appropriate reference signal cannot be used, the reference signal generator changes the number of delay elements through which the signal passes based on the current temperature and the stored temperature change characteristic. Thereby, it is possible to continue outputting a highly accurate reference signal.
  • Patent Document 2 discloses a ⁇ AD converter that can be installed in various electronic circuits.
  • the ⁇ type AD converter performs AD conversion using ⁇ modulation performed by the ⁇ modulator.
  • the ⁇ AD converter disclosed in Patent Document 2 is not particularly described for use, and is not a configuration specialized for an oscillator or a reference signal generator.
  • the minimum unit capable of changing the signal frequency is the delay amount of one delay element. For this reason, it is difficult to accurately match the frequency of the output signal to a desired value.
  • the signal output from the ring oscillator may not converge due to a large change between the frequency higher and lower than the reference signal. As a result, the reference signal output from the ring oscillator becomes unstable.
  • the present invention has been made in view of the above circumstances, and an object thereof is to provide a ring oscillator capable of controlling the frequency according to the delay amount of the delay element, and capable of setting a fine frequency. It is in.
  • a reference signal generator having the following configuration. That is, the reference signal generator includes a ring oscillator, a synchronization control unit, a switching control unit ⁇ , and an output unit.
  • the ring oscillator has a loop-like circuit, and the frequency of a signal to be output can be adjusted by varying the number of delay elements that pass through the circuit once.
  • the synchronization control unit compares a reference signal with a signal output from the ring oscillator or a signal based thereon, and outputs a comparison result.
  • the switching control unit controls the ring oscillator so as to output a plurality of signals having different frequencies based on the comparison result of the synchronization control unit.
  • the output unit outputs a signal output from the ring oscillator or a signal based thereon.
  • the apparent frequency of the reference signal can be set to a frequency between both signals. Accordingly, since the frequency of the reference signal can be set finer than the delay amount of one delay element, the resolution can be improved.
  • the switching control unit controls the ring oscillator so as to output a plurality of signals having different frequencies by using ⁇ modulation.
  • the switching control unit controls the ring oscillator so as to output a plurality of signals having different frequencies by using pulse width modulation.
  • the signal output from the output unit includes a portion where a plurality of signals having different frequencies appear to be switched irregularly.
  • the time interval for switching a plurality of signals having different frequencies is shorter than the time interval for the synchronization control unit to compare.
  • the reference signal generator described above preferably has the following configuration. That is, the reference signal generation device includes an acquisition unit, a characteristic storage unit, and a self-running control unit.
  • the acquisition unit acquires an environment value indicating an environment in which the ring oscillator is used.
  • the characteristic storage unit obtains and stores the relationship between the signal output from the ring oscillator and the environmental value.
  • the self-running control unit When the appropriate reference signal is available, the self-running control unit generates a control signal based on the association stored in the characteristic storage unit.
  • the switching control unit controls the ring oscillator based on a control signal generated by the self-running control unit so as to switch and output a plurality of signals having different frequencies.
  • a reference signal generation method using a simple ring oscillator includes a synchronization control step, a switching control step, and an output step.
  • the reference signal is compared with a signal output from the ring oscillator or a signal based thereon to output a comparison result.
  • the kite controls the ring oscillator so as to switch and output a plurality of signals having different frequencies based on the comparison result in the synchronous control step.
  • the output signal is output from the ring oscillator or a signal based thereon.
  • the apparent frequency of the reference signal can be set to a frequency between both signals. Accordingly, since the frequency of the reference signal can be set finer than the delay amount of one delay element, the resolution can be improved.
  • the block diagram which shows the structure of the reference signal generator which concerns on one Embodiment of this invention The circuit diagram which shows the structure of a ring oscillator.
  • the block diagram which shows the structure of a delta-sigma modulation part The figure which shows the example transmitted while switching two signals using (DELTA) (SIGMA) modulation.
  • FIG. 1 is a block diagram schematically showing a reference signal generator 10 according to the present embodiment.
  • the reference signal generator 10 of the present embodiment is used for a mobile phone base station, a terrestrial digital broadcasting transmitter station, WiMAX (Worldwide Interoperability for Microwave Access) communication equipment, and the like, and is connected to user equipment Provides a reference timing signal and a reference frequency signal. Below, the structure of each part of the reference signal generator 10 is demonstrated.
  • the reference signal generator 10 of the present embodiment includes a GPS receiver 21, a synchronization controller 22, a ⁇ modulator (switching controller) 23, a ring oscillator 24, and a divider 25. And comprising.
  • the synchronization control unit 22, ⁇ modulation unit 23, ring oscillator 24, and frequency dividing unit 25 constitute a PLL circuit 44.
  • GPS A GPS antenna (GNSS antenna) 11 is connected to the input unit 41 of the reference signal generator 10.
  • the positioning signal received by the GPS antenna 11 from the GPS satellite (GNSS satellite) is output to the GPS receiving unit (GNSS receiving unit) 21 via the input unit 41.
  • the GPS receiver 21 generates a reference signal (one pulse signal per second) by performing a positioning calculation based on the positioning signal. This reference signal is appropriately calibrated so as to be accurately synchronized with 1 second of Coordinated Universal Time (UTC).
  • UTC Coordinated Universal Time
  • the ring oscillator 24 is an oscillator in which the frequency of the output signal is controlled by control signals output from the synchronization control unit 22, the ⁇ modulation unit 23, and the like. As shown in FIG. 2, the ring oscillator 24 includes a plurality of delay elements 51, an inverting element (inverter) 52, and a selector 53. The ring oscillator 24 shown in FIG. 2 is configured to include one inverting element 52, but may be configured to include an odd number of inverting elements 52.
  • the ring oscillator 24 has a loop (ring) circuit in which a plurality of delay elements 51 and inverting elements 52 are arranged.
  • This loop-shaped circuit has a circuit that connects between the delay elements 51 and the selector 53. That is, the selector 53 receives a plurality of signals having different numbers of delay elements that have passed. The selector 53 selects and outputs one signal from these signals based on the control signal from the ⁇ modulator 23.
  • the signal selected by the selector 53 is fed back along the loop circuit and passes through the inverting element 52 again.
  • the signal level is inverted from H (High) to ⁇ L (Low), or from L to H.
  • the signal whose output is inverted passes through the delay element 51 and the selector 53 as described above.
  • the pulse signal generated in this way is output as a reference frequency signal from the output unit 42 to the external user system and also to the frequency dividing unit 25.
  • the frequency divider 25 is configured to divide and convert the reference frequency signal input from the ring oscillator 24 from a high frequency to a low frequency, and to output the obtained phase comparison signal to the synchronization controller 22. Yes.
  • the phase comparison signal is also output as a reference timing signal (1PPS signal) from the output unit 43 to the external user side system.
  • the frequency dividing unit 25 divides the 10 MHz signal output from the ring oscillator 24 by a frequency division ratio of 1 / 10,000,000, and a 1 Hz phase comparison signal. Is generated.
  • the synchronization control unit 22 receives this phase comparison saddle signal and the reference signal generated by the GPS receiving unit 21.
  • the synchronization control unit 22 compares the phases of these signals to obtain a phase difference, and generates a signal (frequency control amount) based on the phase difference. Since the phase comparison signal is a 1PPS signal, this comparison is performed at a time interval of once per second. Further, the synchronization control unit 22 performs signal processing such as filter processing on the frequency control amount. Hereinafter, this signal is referred to as a control signal.
  • the synchronization control unit 22 outputs this control signal to the ⁇ modulation unit 23.
  • the synchronization control unit 22 may be configured to output the comparison result of both signals, and the content of the signal processing is arbitrary.
  • the ⁇ modulation unit 23 modulates the control signal output from the synchronization control unit 22.
  • the ⁇ modulation unit 23 includes a subtraction unit (differentiator) 61, an addition unit (integrator) 62, a storage unit 63, and a quantization unit 64.
  • the adder 62 and the storage 63 integrate the input signal and output it to the quantizer 64.
  • the quantizing unit 64 quantizes the output of the adding unit 62 and delays the output by a predetermined time, and then outputs the quantized signal to the subtracting unit 61.
  • the subtractor 61 subtracts the quantized signal from the input signal and outputs the result to the adder 62.
  • the quantization unit 64 can suppress the low frequency component of the quantization noise (noise shaving). Therefore, high resolution can be realized without increasing the number of bits of the quantization unit 64.
  • the ⁇ modulation unit 23 may be a simple primary ⁇ modulation unit as shown in FIG. 3, or may be a secondary or higher-order ⁇ modulation unit.
  • the ⁇ modulator 23 can be configured by a digital circuit. Therefore, since most of the PLL circuit 44 of the present embodiment is composed of digital components, these functions can be easily realized on a semiconductor chip. Therefore, a compact and inexpensive configuration can be realized.
  • the control signal generated by the synchronization control unit 22 and modulated by the ⁇ modulation unit 23 is a 1-bit signal in which 0 and 1 change at high speed, as shown in FIG.
  • the ring oscillator 24 is controlled by this control signal. This will be specifically described below.
  • the minimum unit that can adjust the frequency is one delay amount of the delay element 51. Accordingly, it is difficult to accurately synchronize the signal output from the ring oscillator 24 and the reference signal.
  • the apparent frequency of the signal output from the ring oscillator 24 can be set to the frequency between the two signals by switching and outputting the two signals at a high speed.
  • the result of the comparison between the reference signal by the synchronous control unit 22, a little close to the frequency f k + 1 a between the target frequency of the signal output by the ring oscillator 24 is "frequency f k and the frequency f k + 1 Value ”(see FIG. 4A).
  • the conventional reference signal generator 10 outputs only signal or a frequency f k + 1 of the signal of the frequency f k (or switched every second), the amount of deviation from a target frequency is increased End up.
  • the two signals are output from the ring oscillator 24 while switching at high speed so that the ratio of outputting the signal of frequency f k + 1 is increased.
  • the control signal generated by the synchronization control unit 22 is ⁇ -modulated to generate a signal whose signal value is 1 more than 0 (see FIG. 4A).
  • the ring oscillator 24 receives this signal, the ring oscillator 24 generates a signal having the frequency f k when the signal value of the control signal is 0, and the frequency f k + when the signal value of the control signal is 1.
  • the signal selected by the selector 53 is switched so that the signal 1 is generated. Since the interval between the broken lines shown in FIG. 4A is the interval between the clocks of the ⁇ modulator 23, the signals of the two frequencies are switched at a very high speed.
  • the apparent frequency of the signal output from the ring oscillator 24 becomes a value indicated by favr in FIG.
  • the apparent frequency of the signal output from the ring oscillator 24 can be made closer to the target frequency by switching the two signals at high speed. Therefore, the signal output from the ring oscillator 24 can be accurately synchronized with the reference signal, and the frequency of this signal can be stabilized.
  • the apparent frequency can be changed by changing the ratio of the transmission times of the two signals.
  • FIG. 4B shows an example in which the target frequency is “middle of the frequency f k and the frequency f k + 1 ”.
  • the ring oscillator 24 by controlling the ring oscillator 24 so that the signal and the frequency f k + 1 of the signal of the frequency f k are output at the same rate, close accurately to a target frequency of the frequency of appearance of the signal be able to.
  • FIG. 4C shows an example in which the target frequency is “a value between the frequency f k and the frequency f k + 1 and slightly close to the frequency f k ”.
  • the apparent frequency of this signal can be brought close to the target frequency with high accuracy by controlling the ring oscillator 24 so that the ratio of outputting the signal of the frequency f k is increased.
  • the conventional reference signal generator it is possible to improve the frequency resolution of the signal output from the ring oscillator 24 by outputting the two signals while switching them at high speed.
  • the time interval at which signals can be switched is very long (for example, the timing at which the phase comparison result is output (that is, every second)). Therefore, the conventional reference signal generator only makes the frequency unstable even if the signal is frequently switched.
  • the timing for switching between the frequency f k and the frequency f k + 1 is apparently irregular by using ⁇ modulation.
  • the frequency component is made pseudo-noise, and the frequency component is not biased. Therefore, it is possible to realize a natural reference signal in which the influence of a gradual frequency fluctuation due to signal switching is suppressed.
  • the signal output from the ring oscillator 24 as described above is output from the output unit 42 to the external user system as a reference frequency signal and also input to the frequency dividing unit 25.
  • a loop of the PLL circuit 44 is configured, and the ring oscillator 24 is controlled so that the signal is synchronized with the 1PPS signal as the reference signal. Therefore, as long as the GPS receiver 21 generates a 1PPS signal and supplies it to the reference signal generator 10, and the PLL is locked to the 1PPS signal (synchronized state), the ring is caused by a temperature change or the like. Even if the characteristics of the oscillator 24 fluctuate, the reference signal of the reference signal generator 10 can be maintained with high accuracy.
  • the method of switching a plurality of signals at high speed is not limited to using the ⁇ modulation unit 23, and for example, pulse width modulation (PWM modulation) may be used.
  • PWM modulation pulse width modulation
  • the signal output time can be changed in accordance with the pulse width, so that the output ratio of the two signals can be easily controlled.
  • the reference signal generator 10 of the present modification has a function of transmitting the reference signal while maintaining a predetermined accuracy even when the reference signal cannot be acquired due to lightning strikes, jamming waves, or the like.
  • the delay amount of the delay element 51 of the ring oscillator 24 changes due to a change in voltage or temperature. Therefore, in the self-running saddle state where an appropriate reference signal cannot be obtained, even when the ring oscillator 24 is controlled by the same control signal, the frequency of the output signal may be different.
  • the reference signal generator 10 can continue to output a highly accurate reference signal even in a self-running state by considering the amount of deviation due to this characteristic.
  • the reference signal generating device 10 has a temperature sensor (acquisition unit) 71, a self-running control unit 72, a characteristic storage unit 73, and a switch rod 74 as a configuration for exhibiting this function. .
  • the temperature sensor 71 is a sensor that detects the temperature around the ring oscillator 24. The temperature detected by the temperature sensor 71 is output to the self-running control unit 72.
  • the self-running control unit 72 stores the correspondence relationship (relevance) between the temperature detected by the temperature sensor 71 and the frequency of the signal output from the ring oscillator 24 in the characteristic storage unit 73 in the synchronous state.
  • the self-running control unit 72 obtains the temperature change characteristic of the delay element 51 based on the correspondence stored in the characteristic storage unit 73.
  • the self-running control unit 72 also stores the obtained temperature change characteristic in the characteristic storage unit 73.
  • the temperature change characteristic of the delay element 51 can be obtained when the reference signal generator 10 is not operated (for example, before shipment of the product). Further, the temperature change characteristic obtained before the shipment of the product can be corrected based on data acquired during operation of the reference signal generator 10.
  • control signal generated by the synchronization control unit 22 is input to the self-running control unit 72.
  • the self-running control unit 72 corrects the control signal in consideration of the current temperature detected by the temperature sensor 71 and the temperature change characteristic stored in the characteristic storage unit 73.
  • the switch 74 receives a control signal output from the synchronization control unit 22 and a control signal corrected by the self-running control unit 72.
  • the switch 74 outputs one of the two input control signals to the ring oscillator 24 in response to an instruction from the GPS receiving unit 21 or the synchronization control unit 22.
  • the switch 74 outputs the control signal output by the synchronization control unit 22 from the switch 74.
  • the GPS receiving unit 21 or the synchronization control unit 22 causes the switch 74 to output the control signal output from the self-running control unit 72 from the switch 74. Since the control signal output from the self-running control unit 72 is determined in consideration of environmental changes (temperature changes, etc.), even if the environment changes in the self-running state, a highly accurate reference The signal can be continuously output. In this case, since the accuracy of the reference signal is considered low, the synchronization control unit 22 does not perform phase comparison.
  • the ring oscillator 24 of the present application can set the frequency in detail, it can be accurately adjusted to the desired frequency in the synchronized state. Therefore, the frequency shift at the start of the self-running control can be reduced.
  • the ring oscillator 24 of the present application can set the frequency in detail, it can be accurately adjusted to a desired frequency even in the self-running state. From the above, the reference signal generator 10 of the present modification can suppress the frequency deviation amount in the self-running state as compared with the conventional case.
  • the reference signal generation device 10 of the present embodiment and the modification includes the ring oscillator 24, the synchronization control unit 22, the ⁇ modulation unit 23, and the output units 42 and 43.
  • the ring oscillator 24 has a loop-like circuit, and the frequency of the signal to be output can be adjusted by changing the number of delay elements 51 that pass through the circuit once.
  • the synchronization control unit 22 compares the reference signal with a signal output from the ring oscillator 24 or a signal based thereon, and outputs a comparison result (synchronization control step).
  • the ⁇ modulator 23 controls the ring oscillator 24 based on the comparison result of the synchronization control unit so as to output a plurality of signals having different frequencies (switching control step).
  • the output units 42 and 43 output a signal output from the ring oscillator 24 or a signal based thereon (output step).
  • the reference signal generation method is realized.
  • the apparent frequency of the reference signal can be set to a frequency between both signals. Accordingly, since the frequency of the reference signal can be set finer than the delay amount of one delay element, the resolution can be improved.
  • the configuration includes a synchronization circuit (PLL circuit) that compares phases, but a configuration that includes a synchronization circuit (FLL circuit) that compares frequencies instead may be used.
  • PLL circuit synchronization circuit
  • FLL circuit synchronization circuit
  • the GPS antenna 11 is connected to a substrate on which the synchronization control unit 22 and the like are formed via a predetermined cable.
  • a configuration in which the ⁇ ⁇ ⁇ GPS antenna 11 is directly attached to the board may be employed. In this case, since no cable is required, the installation cost of the reference signal generator can be reduced.
  • the configuration can be appropriately changed as long as the configuration uses GNSS (Global Navigation Satellite System).
  • GNSS Global Navigation Satellite System
  • the configuration can be changed to a configuration in which a reference signal is generated based on a signal from a GLONASS satellite or a GALILEO satellite. Further, it may be configured to acquire a reference signal from an external device.
  • the ambient temperature of the ring oscillator 24 is acquired as an environmental value.
  • the voltage of the ring oscillator 24 can be acquired as the environmental value.
  • the GPS receiving unit 21 can be changed to a configuration that generates a signal other than 1 Hz such as PP2S as a reference signal instead of 1PPS. Further, the GPS receiver 21 may be arranged outside the reference signal generator 10 instead of inside.
  • the units included in the reference signal generation device 10 can be configured by software instead of being configured by hardware.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)
  • Electric Clocks (AREA)

Abstract

[Problem] To provide a ring oscillator capable of controlling frequency according to the delay amount of a delay element, with a structure for which fine-level frequency setting is possible. [Solution] A reference signal generation device 10 is provided with: a ring oscillator 24; a synchronization control unit 22; a ΔΣ modulation unit 23; and output units 42, 43. With the ring oscillator 24, the frequency of outputted signals can be adjusted. The synchronization control unit 22 compares a reference signal with signals outputted by the ring oscillator 24, or signals based thereon, and outputs the comparison results. Based on the comparison results of the synchronization control unit, the ΔΣ modulation unit 23 controls the ring oscillator 24 to perform output while switching a plurality of signals having different frequencies. The output units 42, 43 output signals that were outputted by the ring oscillator 24, or signals based thereon.

Description

基準信号発生装置及び基準信号発生方法Reference signal generator and reference signal generation method
　本発明は、主要には、リングオシレータを備えた基準信号発生装置に関する。 The present invention mainly relates to a reference signal generation device including a ring oscillator.
　 従来から、出力する信号の周波数を調整可能な発振器として、リングオシレータが知られている。リングオシレータとは、ループ状（リング状）の回路を備えて おり、信号がループ状の回路を１周するのに掛かる時間（遅延時間）を変化させることで、所定の周波数のパルス信号を生成することができる。特許文献１は、 この種のリングオシレータを備えた基準信号発生装置を開示する。 Conventionally, a ring oscillator is known as an oscillator that can adjust the frequency of an output signal. A ring oscillator is equipped with a loop-shaped (ring-shaped) circuit, and generates a pulse signal with a predetermined frequency by changing the time (delay time) that it takes for the signal to make a round of the loop-shaped circuit. can do. Patent Document 1 discloses a reference signal generator having such a ring oscillator.
　特許文献１のリングオシレータは、分岐を有するループ状 の回路及び複数の遅延素子を備えており、信号が通る経路によって通過する遅延素子の個数が異なる。基準信号発生装置は、所定の経路を通った信号が出力され るように制御することで、リングオシレータから所望の周波数の信号を出力させることができる。基準信号発生装置は、リングオシレータが出力する信号を高精 度なリファレンス信号に同期させることで、高精度な周波数又はタイミングの信号（基準信号）を生成する。 The ring oscillator disclosed in Patent Document 1 includes a loop-like circuit having a branch and a plurality of delay elements, and the number of delay elements that pass depends on a path through which a signal passes. The reference signal generator can output a signal having a desired frequency from the ring oscillator by controlling so that a signal passing through a predetermined path is output. The reference signal generator generates a highly accurate frequency or timing signal (reference signal) by synchronizing a signal output from the ring oscillator with a highly accurate reference signal.
　また、特許文献 １には、基準信号発生装置が自走制御を行う点についても記載されている。自走制御とは、適切なリファレンス信号が利用できない場合に行われ、リファレンス 信号を利用せずに高精度な基準信号を生成する制御である。具体的には、基準信号発生装置は、適切なリファレンス信号が利用可能な間に遅延素子の遅延量の温 度変化特性等を求めて記憶しておく。そして、基準信号発生装置は、適切なリファレンス信号が利用できなくなった場合、現在の温度と、記憶した温度変化特性 と、に基づいて、信号が通過する遅延素子の個数を変化させる。これにより、高精度な基準信号を出力し続けることができる。 Patent Document 1 also describes that the reference signal generator performs self-running control. The self-running control is performed when an appropriate reference signal cannot be used, and is a control that generates a highly accurate reference signal without using a reference soot signal. Specifically, the reference signal generator obtains and stores the temperature variation characteristic of the delay amount of the delay element while an appropriate reference signal is available. Then, when an appropriate reference signal cannot be used, the reference signal generator changes the number of delay elements through which the signal passes based on the current temperature and the stored temperature change characteristic. Thereby, it is possible to continue outputting a highly accurate reference signal.
　 特許文献２には、様々な電子回路に設置可能なΔΣ型ＡＤ変換器が開示されている。ΔΣ型ＡＤ変換器は、ΔΣ変調器が行うΔΣ変調を利用して、ＡＤ変換を行 う。なお、特許文献２のΔΣ型ＡＤ変換器は、特に用途が記載されておらず、発振器又は基準信号発生装置に特化した構成でもない。 Patent Document 2 discloses a ΔΣ AD converter that can be installed in various electronic circuits. The ΔΣ type AD converter performs AD conversion using ΔΣ modulation performed by the ΔΣ modulator. The ΔΣ AD converter disclosed in Patent Document 2 is not particularly described for use, and is not a configuration specialized for an oscillator or a reference signal generator.
特開２０１０－２７３２９９号公報JP 2010-273299 A 特開２００７－２４３６２０号公報JP 2007-243620 A
　ところで、特許文献１のようなリングオシレータにおいて、信号の周波数を変更可能な最小単位は、遅延素子１個の遅延量である。そのため、出力する信号の周波数を所望の値に精度良く合わせることが困難であった。 By the way, in the ring oscillator as in Patent Document 1, the minimum unit capable of changing the signal frequency is the delay amount of one delay element. For this reason, it is difficult to accurately match the frequency of the output signal to a desired value.
　 従って、このリングオシレータを備える基準信号発生装置において、リングオシレータが出力する信号が、リファレンス信号よりも高い周波数と低い周波数との 間を大きく変化して収束しない場合がある。その結果、リングオシレータから出力される基準信号が不安定になってしまう。 Therefore, in a reference signal generating device provided with this ring oscillator, the signal output from the ring oscillator may not converge due to a large change between the frequency higher and lower than the reference signal. As a result, the reference signal output from the ring oscillator becomes unstable.
　本発明は以上の事情に鑑みてされたものであり、その目的は、遅延素子の遅延量に応じて周波数を制御可能なリングオシレータであって、細かな周波数を設定可能な構成を提供することにある。 The present invention has been made in view of the above circumstances, and an object thereof is to provide a ring oscillator capable of controlling the frequency according to the delay amount of the delay element, and capable of setting a fine frequency. It is in.
課題を解決するための手段及び効果Means and effects for solving the problems
　本発明の解決しようとする課題は以上の如くであり、次にこの課題を解決するための手段とその効果を説明する。 The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.
　 本発明の第１の観点によれば、以下の構成の基準信号発生装置が提供される。即ち、この基準信号発生装置は、リングオシレータと、同期制御部と、切替制御部 と、出力部と、を備える。前記リングオシレータは、ループ状の回路を有しており、当該回路を１周するときに通過する遅延素子の数を異ならせることで、出力 する信号の周波数を調整可能である。前記同期制御部は、リファレンス信号と、前記リングオシレータが出力する信号又はそれに基づく信号と、を比較して比較 結果を出力する。前記切替制御部は、前記同期制御部の比較結果に基づいて、周波数が異なる複数の信号を切り替えながら出力するように前記リングオシレータ を制御する。前記出力部は、前記リングオシレータが出力した信号又はそれに基づく信号を出力する。 According to a first aspect of the present invention, a reference signal generator having the following configuration is provided. That is, the reference signal generator includes a ring oscillator, a synchronization control unit, a switching control unit 出力, and an output unit. The ring oscillator has a loop-like circuit, and the frequency of a signal to be output can be adjusted by varying the number of delay elements that pass through the circuit once. The synchronization control unit compares a reference signal with a signal output from the ring oscillator or a signal based thereon, and outputs a comparison result. The switching control unit controls the ring oscillator so as to output a plurality of signals having different frequencies based on the comparison result of the synchronization control unit. The output unit outputs a signal output from the ring oscillator or a signal based thereon.
　これにより、例えば周波数が異なる２つの信号を切り替えることで、基準信号の見かけの周波数を両信号の間の周波数とすることができる。従って、基準信号の周波数を遅延素子の１個の遅延量よりも細かく設定できるので、分解能を向上させることができる。 Thus, for example, by switching two signals having different frequencies, the apparent frequency of the reference signal can be set to a frequency between both signals. Accordingly, since the frequency of the reference signal can be set finer than the delay amount of one delay element, the resolution can be improved.
　前記の基準信号発生装置においては、前記切替制御部は、ΔΣ変調を用いて、周波数が異なる複数の信号を切り替えながら出力するように前記リングオシレータを制御することが好ましい。 In the reference signal generator, it is preferable that the switching control unit controls the ring oscillator so as to output a plurality of signals having different frequencies by using ΔΣ modulation.
　これにより、複数の信号を高速（ΔΣ変調部のクロック周波数）で切り替えることができるので、信号の切替えの影響が抑えられた自然な基準信号を実現できる。 Thereby, since a plurality of signals can be switched at high speed (clock frequency of the ΔΣ modulation unit), a natural reference signal in which the influence of signal switching is suppressed can be realized.
　前記の基準信号発生装置においては、前記切替制御部は、パルス幅変調を用いて、周波数が異なる複数の信号を切り替えながら出力するように前記リングオシレータを制御することが好ましい。 In the reference signal generator, it is preferable that the switching control unit controls the ring oscillator so as to output a plurality of signals having different frequencies by using pulse width modulation.
　これにより、パルス幅に応じて信号の出力時間を変化させることができるので、複数の信号の出力比率（どの信号をどれだけの時間出力するか）を簡単に制御することができる。 This makes it possible to change the signal output time according to the pulse width, so that the output ratio of multiple signals (which signal is output for which time) can be easily controlled.
　前記の基準信号発生装置においては、前記出力部が出力する信号には、周波数が異なる複数の信号が見かけ上、不規則に切り替わる部分が含まれることが好ましい。 In the reference signal generation device, it is preferable that the signal output from the output unit includes a portion where a plurality of signals having different frequencies appear to be switched irregularly.
　これにより、信号の切替えの影響が抑えられた自然な基準信号を出力できる。 This makes it possible to output a natural reference signal in which the influence of signal switching is suppressed.
　前記の基準信号発生装置においては、周波数が異なる複数の信号を切り替える時間間隔は、前記同期制御部が比較を行う時間間隔よりも短いことが好ましい。 In the reference signal generator, it is preferable that the time interval for switching a plurality of signals having different frequencies is shorter than the time interval for the synchronization control unit to compare.
　これにより、周波数が異なる複数の信号を高速で切り替えることができるので、信号の切替えの影響が抑えられた自然な基準信号を出力できる。 This allows a plurality of signals with different frequencies to be switched at a high speed, so that a natural reference signal in which the influence of the signal switching is suppressed can be output.
　 前記の基準信号発生装置においては、以下の構成とすることが好ましい。即ち、この基準信号発生装置は、取得部と、特性記憶部と、自走制御部と、を備える。 前記取得部は、前記リングオシレータが使用される環境を示す環境値を取得する。前記特性記憶部は、前記リングオシレータが出力する信号と前記環境値との関 連性を求めて記憶する。前記自走制御部は、適切なリファレンス信号が利用できるときは、前記特性記憶部が記憶する前記関連性に基づいて、制御信号を生成す る。前記切替制御部は、前記自走制御部が生成した制御信号に基づいて、周波数が異なる複数の信号を切り替えながら出力するように前記リングオシレータを制 御する。 The reference signal generator described above preferably has the following configuration. That is, the reference signal generation device includes an acquisition unit, a characteristic storage unit, and a self-running control unit. The acquisition unit acquires an environment value indicating an environment in which the ring oscillator is used. The characteristic storage unit obtains and stores the relationship between the signal output from the ring oscillator and the environmental value. When the appropriate reference signal is available, the self-running control unit generates a control signal based on the association stored in the characteristic storage unit. The switching control unit controls the ring oscillator based on a control signal generated by the self-running control unit so as to switch and output a plurality of signals having different frequencies.
　これにより、適切なリファレンス信号が利用できなくなった場合であっても、高精度な基準信号を出力し続けることができる。また、本願のリングオシレータは高い分解能を有しているため、自走制御中であっても高精度な基準信号を維持することができる。 This makes it possible to continue outputting a highly accurate reference signal even when an appropriate reference signal cannot be used. In addition, since the ring oscillator of the present application has high resolution, it is possible to maintain a highly accurate reference signal even during self-running control.
　 本発明の第２の観点によれば、ループ状の回路を有しており、当該回路を１周するときに通過する遅延素子の数を異ならせることで、出力する信号の周波数を調 整可能なリングオシレータを用いた基準信号発生方法が提供される。この基準信号発生方法は、同期制御工程と、切替制御工程と、出力工程と、を含む。前記同 期制御工程では、リファレンス信号と、前記リングオシレータが出力する信号又はそれに基づく信号と、を比較して比較結果を出力する。前記切替制御工程で は、前記同期制御工程での比較結果に基づいて、周波数が異なる複数の信号を切り替えながら出力するように前記リングオシレータを制御する。前記出力工で程 は、前記リングオシレータが出力した信号又はそれに基づく信号を出力する。 According to the second aspect of the present invention, it has a loop-shaped circuit, and the frequency of the output signal can be adjusted by changing the number of delay elements that pass through the circuit once. A reference signal generation method using a simple ring oscillator is provided. The reference signal generation method includes a synchronization control step, a switching control step, and an output step. In the synchronous control step, the reference signal is compared with a signal output from the ring oscillator or a signal based thereon to output a comparison result. In the switching control step, the kite controls the ring oscillator so as to switch and output a plurality of signals having different frequencies based on the comparison result in the synchronous control step. In the output process, the output signal is output from the ring oscillator or a signal based thereon.
　これにより、例えば周波数が異なる２つの信号を切り替えることで、基準信号の見かけの周波数を両信号の間の周波数とすることができる。従って、基準信号の周波数を遅延素子の１個の遅延量よりも細かく設定できるので、分解能を向上させることができる。 Thus, for example, by switching two signals having different frequencies, the apparent frequency of the reference signal can be set to a frequency between both signals. Accordingly, since the frequency of the reference signal can be set finer than the delay amount of one delay element, the resolution can be improved.
本発明の一実施形態に係る基準信号発生装置の構成を示すブロック図。The block diagram which shows the structure of the reference signal generator which concerns on one Embodiment of this invention. リングオシレータの構成を示す回路図。The circuit diagram which shows the structure of a ring oscillator. ΔΣ変調部の構成を示すブロック図。The block diagram which shows the structure of a delta-sigma modulation part. ΔΣ変調を用いて２つの信号を切り替えながら送信する例を示す図。The figure which shows the example transmitted while switching two signals using (DELTA) (SIGMA) modulation. 自走制御が可能な基準信号発生装置を示すブロック図。The block diagram which shows the reference signal generator in which self-running control is possible.
　次に発明の実施の形態について説明する。初めに、図１を参照して、基準信号発生装置１０の全体構成について説明する。図１は、本実施形態の基準信号発生装置１０を概略的に示したブロック図である。 Next, embodiments of the invention will be described. First, the overall configuration of the reference signal generator 10 will be described with reference to FIG. FIG. 1 is a block diagram schematically showing a reference signal generator 10 according to the present embodiment.
　 本実施形態の基準信号発生装置１０は、携帯電話の基地局、地上デジタル放送の送信局及びＷｉＭＡＸ（Ｗｏｒｌｄｗｉｄｅ　 Ｉｎｔｅｒｏｐｅｒａｂｉｌｉｔｙ　ｆｏｒ　Ｍｉｃｒｏｗａｖｅ　Ａｃｃｅｓｓ）の通信設備等に用いられるものであり、接続されるユーザ側の機器に基準タ イミング信号や基準周波数信号を提供するものである。以下に、基準信号発生装置１０の各部の構成について説明する。 The reference signal generator 10 of the present embodiment is used for a mobile phone base station, a terrestrial digital broadcasting transmitter station, WiMAX (Worldwide Interoperability for Microwave Access) communication equipment, and the like, and is connected to user equipment Provides a reference timing signal and a reference frequency signal. Below, the structure of each part of the reference signal generator 10 is demonstrated.
　図１ に示すように、本実施形態の基準信号発生装置１０は、ＧＰＳ受信部２１と、同期制御部２２と、ΔΣ変調部（切替制御部）２３と、リングオシレータ２４と、 分周部２５と、を備える。また、同期制御部２２、ΔΣ変調部２３、リングオシレータ２４、及び分周部２５は、ＰＬＬ回路４４を構成している。 As shown in FIG. 1B, the reference signal generator 10 of the present embodiment includes a GPS receiver 21, a synchronization controller 22, a ΔΣ modulator (switching controller) 23, a ring oscillator 24, and a divider 25. And comprising. The synchronization control unit 22, ΔΣ modulation unit 23, ring oscillator 24, and frequency dividing unit 25 constitute a PLL circuit 44.
　 基準信号発生装置１０の入力部４１には、ＧＰＳアンテナ（ＧＮＳＳアンテナ）１１が接続されている。ＧＰＳアンテナ１１がＧＰＳ衛星（ＧＮＳＳ衛星）から 受信した測位信号は、この入力部４１を介して、ＧＰＳ受信部（ＧＮＳＳ受信部）２１へ出力される。ＧＰＳ受信部２１は、この測位信号に基づいて測位計算を 行うことで、リファレンス信号（１秒に１回のパルス信号）を生成する。このリファレンス信号は、協定世界時（ＵＴＣ）の１秒に正確に同期するように適宜較 正されている。 ＧＰＳ A GPS antenna (GNSS antenna) 11 is connected to the input unit 41 of the reference signal generator 10. The positioning signal received by the GPS antenna 11 from the GPS satellite (GNSS satellite) is output to the GPS receiving unit (GNSS receiving unit) 21 via the input unit 41. The GPS receiver 21 generates a reference signal (one pulse signal per second) by performing a positioning calculation based on the positioning signal. This reference signal is appropriately calibrated so as to be accurately synchronized with 1 second of Coordinated Universal Time (UTC).
　リングオシレータ２４は、同期制御部２２及びΔΣ変調部２３等が出力する制御信号によって、出力する信号 の周波数が制御される発振器である。図２に示すようにリングオシレータ２４は、複数の遅延素子５１と、反転素子（インバータ）５２と、セレクタ５３と、を 備える。なお、図２に示すリングオシレータ２４は、反転素子５２を１つ備える構成だが、反転素子５２を奇数個備える構成であっても良い。 The ring oscillator 24 is an oscillator in which the frequency of the output signal is controlled by control signals output from the synchronization control unit 22, the ΔΣ modulation unit 23, and the like. As shown in FIG. 2, the ring oscillator 24 includes a plurality of delay elements 51, an inverting element (inverter) 52, and a selector 53. The ring oscillator 24 shown in FIG. 2 is configured to include one inverting element 52, but may be configured to include an odd number of inverting elements 52.
　 リングオシレータ２４は、複数の遅延素子５１及び反転素子５２が配置されたループ状（リング状）の回路を有している。このループ状の回路は、遅延素子５１ 同士の間とセレクタ５３とを接続する回路を有している。つまり、セレクタ５３には、通過した遅延素子の数が異なる複数の信号が入力されることとなる。セレ クタ５３は、ΔΣ変調部２３からの制御信号に基づいて、これらの信号から１つの信号を選択して出力する。 The ring oscillator 24 has a loop (ring) circuit in which a plurality of delay elements 51 and inverting elements 52 are arranged. This loop-shaped circuit has a circuit that connects between the delay elements 51 and the selector 53. That is, the selector 53 receives a plurality of signals having different numbers of delay elements that have passed. The selector 53 selects and outputs one signal from these signals based on the control signal from the ΔΣ modulator 23.
　セレクタ５３に よって選択された信号は、ループ状の回路に沿って帰還し、再び反転素子５２を通過する。この反転素子５２によって、信号のレベルはＨ（Ｈｉｇｈ）から Ｌ（Ｌｏｗ）、又は、ＬからＨへ反転する。出力が反転した信号は、上記と同様に遅延素子５１及びセレクタ５３を通過する。上記の動作が繰り返されること で、信号のレベルがＨ、Ｌ、Ｈ、Ｌ、・・・と所定の周波数で切り替わるパルス信号を生成することができる。 The signal selected by the selector 53 is fed back along the loop circuit and passes through the inverting element 52 again. By the inverting element 52, the signal level is inverted from H (High) to 、 L (Low), or from L to H. The signal whose output is inverted passes through the delay element 51 and the selector 53 as described above. By repeating the above operation, it is possible to generate a pulse signal whose signal level is switched at a predetermined frequency such as H, L, H, L,.
　このようにして生成されたパルス信号は、基準周波数信号として出力部４２から外部のユーザ側のシステムへ出力されるとともに、分周部２５に入力される。 The pulse signal generated in this way is output as a reference frequency signal from the output unit 42 to the external user system and also to the frequency dividing unit 25.
　 分周部２５は、リングオシレータ２４から入力される基準周波数信号を分周して高い周波数から低い周波数に変換し、得られた位相比較用信号を同期制御部２２ へ出力するように構成されている。また、この位相比較用信号は、基準タイミング信号（１ＰＰＳ信号）として出力部４３から外部のユーザ側のシステムに対し ても出力される。例えば、リングオシレータ２４が出力する基準周波数が１０ＭＨｚである場合、分周部２５は、リングオシレータ２４が出力する１０ＭＨｚの 信号を分周比１／１０００００００で分周して、１Ｈｚの位相比較用信号を生成する。 The frequency divider 25 is configured to divide and convert the reference frequency signal input from the ring oscillator 24 from a high frequency to a low frequency, and to output the obtained phase comparison signal to the synchronization controller 22. Yes. The phase comparison signal is also output as a reference timing signal (1PPS signal) from the output unit 43 to the external user side system. For example, when the reference frequency output from the ring oscillator 24 is 10 MHz, the frequency dividing unit 25 divides the 10 MHz signal output from the ring oscillator 24 by a frequency division ratio of 1 / 10,000,000, and a 1 Hz phase comparison signal. Is generated.
　同期制御部２２には、この位相比較用 信号と、ＧＰＳ受信部２１が生成したリファレンス信号と、が入力される。同期制御部２２は、これらの信号の位相を比較して位相差を求め、その位相差に基づ く信号（周波数制御量）を生成する。なお、位相比較用信号は１ＰＰＳ信号なので、この比較は、１秒に１回の時間間隔で行われる。また、同期制御部２２は、 この周波数制御量にフィルタ処理等の信号処理を行う。以下では、この信号を制御信号と称する。同期制御部２２は、この制御信号をΔΣ変調部２３へ出力す る。なお、同期制御部２２は、両信号の比較結果を出力する構成であれば良く、信号処理の内容は任意である。 The synchronization control unit 22 receives this phase comparison saddle signal and the reference signal generated by the GPS receiving unit 21. The synchronization control unit 22 compares the phases of these signals to obtain a phase difference, and generates a signal (frequency control amount) based on the phase difference. Since the phase comparison signal is a 1PPS signal, this comparison is performed at a time interval of once per second. Further, the synchronization control unit 22 performs signal processing such as filter processing on the frequency control amount. Hereinafter, this signal is referred to as a control signal. The synchronization control unit 22 outputs this control signal to the ΔΣ modulation unit 23. The synchronization control unit 22 may be configured to output the comparison result of both signals, and the content of the signal processing is arbitrary.
　ΔΣ変調部２３は、同期制御部２２が出力した制御信号を変調する。ΔΣ変調部２３は、図３に示すように、減算部（微分器）６１と、加算部（積分器）６２と、記憶部６３と、量子化部６４と、を備えている。 The ΔΣ modulation unit 23 modulates the control signal output from the synchronization control unit 22. As shown in FIG. 3, the ΔΣ modulation unit 23 includes a subtraction unit (differentiator) 61, an addition unit (integrator) 62, a storage unit 63, and a quantization unit 64.
　 加算部６２及び記憶部６３は、入力される信号を積分して量子化部６４へ出力する。量子化部６４は、加算部６２の出力を量子化して、所定時間だけ遅延させた 後に、量子化した信号を減算部６１へ出力する。減算部６１は、入力信号から、この量子化された信号を減算して、加算部６２へ出力する。 The adder 62 and the storage 63 integrate the input signal and output it to the quantizer 64. The quantizing unit 64 quantizes the output of the adding unit 62 and delays the output by a predetermined time, and then outputs the quantized signal to the subtracting unit 61. The subtractor 61 subtracts the quantized signal from the input signal and outputs the result to the adder 62.
　 このように、量子化雑音を含む量子化された入力信号をフィードバックすることにより、量子化部６４では、量子化雑音の低周波成分を抑えることができる（ノ イズシェービング）。そのため、量子化部６４のビット数を高くすることなく高い分解能を実現することができる。なお、ΔΣ変調部２３は、図３に示したよう な一次のΔΣ変調部であっても良いし、２次以上のΔΣ変調部であっても良い。 As described above, by feeding back the quantized input signal including the quantization noise, the quantization unit 64 can suppress the low frequency component of the quantization noise (noise shaving). Therefore, high resolution can be realized without increasing the number of bits of the quantization unit 64. Note that the ΔΣ modulation unit 23 may be a simple primary ΔΣ modulation unit as shown in FIG. 3, or may be a secondary or higher-order ΔΣ modulation unit.
　また、ΔΣ変調部２３は、デジタル回路で構成することができる。従って、本実施形態のＰＬＬ回路４４は、大部分がデジタル部品で構成されるため、これらの機能を容易に半導体チップ上で実現することができる。従って、コンパクトかつ安価な構成が実現できる。 Further, the ΔΣ modulator 23 can be configured by a digital circuit. Therefore, since most of the PLL circuit 44 of the present embodiment is composed of digital components, these functions can be easily realized on a semiconductor chip. Therefore, a compact and inexpensive configuration can be realized.
　同期制御部２２が生成し、ΔΣ変調部２３によって変調された制御信号は、図４に示すように、０と１とが高速で変化する１ビットの信号である。リングオシレータ２４は、この制御信号によって制御される。以下、具体的に説明する。 The control signal generated by the synchronization control unit 22 and modulated by the ΔΣ modulation unit 23 is a 1-bit signal in which 0 and 1 change at high speed, as shown in FIG. The ring oscillator 24 is controlled by this control signal. This will be specifically described below.
　 従来は、通過する遅延素子５１の個数を利用したリングオシレータ２４では、周波数を調整できる最小単位は、遅延素子５１の１つの遅延量であった。従って、 リングオシレータ２４の出力する信号と、リファレンス信号と、を正確に同期させることは困難であった。この点、本実施形態では、２つの信号を高速で切り替 えながら出力することで、リングオシレータ２４が出力する信号の見かけの周波数を両信号の間の周波数とすることができる。 Conventionally, in the ring oscillator 24 that uses the number of delay elements 51 that pass through, the minimum unit that can adjust the frequency is one delay amount of the delay element 51. Accordingly, it is difficult to accurately synchronize the signal output from the ring oscillator 24 and the reference signal. In this regard, in the present embodiment, the apparent frequency of the signal output from the ring oscillator 24 can be set to the frequency between the two signals by switching and outputting the two signals at a high speed.
　例えば、同期制御部２２によるリファレンス信号との比較の結果、リングオシレータ２４が出力する信号の目標の周波数が「周波数ｆkと周波数ｆk+1の間であって周波数ｆk+1に少し近い値」となったとする（図４（ａ）を参照）。この場合、従来の基準信号発生装置１０は、周波数ｆkの信号又は周波数ｆk+1の信号のみを出力する（又は１秒毎に切り替える）ため、目標とする周波数からのズレ量が大きくなってしまう。 For example, the result of the comparison between the reference signal by the synchronous control unit 22, a little close to the frequency f k + 1 a between the target frequency of the signal output by the ring oscillator 24 is "frequency f k and the frequency f k + 1 Value ”(see FIG. 4A). In this case, the conventional reference signal generator 10 outputs only signal or a frequency f k + 1 of the signal of the frequency f k (or switched every second), the amount of deviation from a target frequency is increased End up.
　これに対し、本実施形態では、周波数ｆk+1の 信号を出力する割合が多くなるように、２つの信号を高速に切り替えながらリングオシレータ２４から出力させる。具体的には、同期制御部２２が生成した制御 信号をΔΣ変調することで、信号値が０よりも１の方が多くなる信号が生成される（図４（ａ）を参照）。この信号を受信したリングオシレータ２４は、制御信 号の信号値が０である場合は周波数ｆkの信号を生成するように、かつ、制御信号の信号値が１である場合は周波数ｆk+1の信号を生成するようにセレクタ５３が選択する信号を切り替える。なお、図４（ａ）に示す破線の間隔はΔΣ変調部２３のクロックの間隔であるため、２つの周波数の信号は非常に高速で切り替えられている。 On the other hand, in the present embodiment, the two signals are output from the ring oscillator 24 while switching at high speed so that the ratio of outputting the signal of frequency f k + 1 is increased. Specifically, the control signal generated by the synchronization control unit 22 is ΔΣ-modulated to generate a signal whose signal value is 1 more than 0 (see FIG. 4A). Receiving this signal, the ring oscillator 24 generates a signal having the frequency f k when the signal value of the control signal is 0, and the frequency f k + when the signal value of the control signal is 1. The signal selected by the selector 53 is switched so that the signal 1 is generated. Since the interval between the broken lines shown in FIG. 4A is the interval between the clocks of the ΔΣ modulator 23, the signals of the two frequencies are switched at a very high speed.
　これにより、リングオシレータ２４が出力する信号の見かけの周波数は、図４（ａ）のｆavrに 示す値となる。このように、２つの信号を高速で切り替えることで、リングオシレータ２４が出力する信号の見かけの周波数を目標とする周波数により近づける ことができる。従って、リングオシレータ２４が出力する信号をリファレンス信号に正確に同期させるとともに、この信号の周波数を安定させることができる。 As a result, the apparent frequency of the signal output from the ring oscillator 24 becomes a value indicated by favr in FIG. In this manner, the apparent frequency of the signal output from the ring oscillator 24 can be made closer to the target frequency by switching the two signals at high speed. Therefore, the signal output from the ring oscillator 24 can be accurately synchronized with the reference signal, and the frequency of this signal can be stabilized.
　また、２つの信号の送信時間の割合を変更することで、見かけの周波数を変化させることができる。具体的には、また、図４（ｂ）には、目標とする周波数が「周波数ｆkと周波数ｆk+1の中間」である場合の例が示されている。この場合、周波数ｆkの信号と周波数ｆk+1の信号とが同じ割合で出力されるようにリングオシレータ２４を制御することで、この信号の見かけの周波数を目標とする周波数に精度良く近づけることができる。 Also, the apparent frequency can be changed by changing the ratio of the transmission times of the two signals. Specifically, FIG. 4B shows an example in which the target frequency is “middle of the frequency f k and the frequency f k + 1 ”. In this case, by controlling the ring oscillator 24 so that the signal and the frequency f k + 1 of the signal of the frequency f k are output at the same rate, close accurately to a target frequency of the frequency of appearance of the signal be able to.
　また、図４（ｃ）には、目標とする周波数が「周波数ｆkと周波数ｆk+1の間であって周波数ｆkに少し近い値」である場合の例が示されている。この場合、周波数ｆkの信号を出力する割合が多くなるようにリングオシレータ２４を制御することで、この信号の見かけの周波数を目標とする周波数に精度良く近づけることができる。 FIG. 4C shows an example in which the target frequency is “a value between the frequency f k and the frequency f k + 1 and slightly close to the frequency f k ”. In this case, the apparent frequency of this signal can be brought close to the target frequency with high accuracy by controlling the ring oscillator 24 so that the ratio of outputting the signal of the frequency f k is increased.
　 このように本実施形態では、２つの信号を高速で切り替えながら出力することで、リングオシレータ２４が出力する信号の周波数の分解能を向上させることがで きる。なお、従来の基準信号発生装置は、信号を切替可能な時間間隔が非常に長かった（例えば位相比較の結果が出力されるタイミング（即ち１秒毎に））。 従って、従来の基準信号発生装置は、信号を頻繁に切り替えても周波数を不安定にするだけであった。 Thus, in this embodiment, it is possible to improve the frequency resolution of the signal output from the ring oscillator 24 by outputting the two signals while switching them at high speed. In the conventional reference signal generator, the time interval at which signals can be switched is very long (for example, the timing at which the phase comparison result is output (that is, every second)). Therefore, the conventional reference signal generator only makes the frequency unstable even if the signal is frequently switched.
　また、図４（ａ）及び図４（ｃ）では、ΔΣ変調を利用することにより、周波数ｆkと周波数ｆk+1を切り替えるタイミングが見かけ上、不規則になっている。これにより、周波数成分が擬似雑音化され、周波数成分に偏りがなくなるため、信号の切替えによる緩やかな周波数変動の影響が抑えられた自然な基準信号を実現できる。 In FIGS. 4A and 4C, the timing for switching between the frequency f k and the frequency f k + 1 is apparently irregular by using ΔΣ modulation. As a result, the frequency component is made pseudo-noise, and the frequency component is not biased. Therefore, it is possible to realize a natural reference signal in which the influence of a gradual frequency fluctuation due to signal switching is suppressed.
　上記のようにしてリングオシレータ２４が出力した信号は、基準周波数信号として出力部４２から外部のユーザ側のシステムへ出力されるとともに、分周部２５に入力される。 The signal output from the ring oscillator 24 as described above is output from the output unit 42 to the external user system as a reference frequency signal and also input to the frequency dividing unit 25.
　 以上に説明した構成によって、ＰＬＬ回路４４のループが構成され、リファレンス信号としての１ＰＰＳ信号に信号が同期するようにリングオシレータ２４が制 御される。従って、ＧＰＳ受信部２１が１ＰＰＳ信号を生成して基準信号発生装置１０に供給し、当該１ＰＰＳ信号に対してＰＬＬがロックしている（同期状態 である）限り、温度変化等に起因してリングオシレータ２４の特性の変動が生じたとしても、基準信号発生装置１０の基準信号を高精度に保つことができる。 With the configuration described above, a loop of the PLL circuit 44 is configured, and the ring oscillator 24 is controlled so that the signal is synchronized with the 1PPS signal as the reference signal. Therefore, as long as the GPS receiver 21 generates a 1PPS signal and supplies it to the reference signal generator 10, and the PLL is locked to the 1PPS signal (synchronized state), the ring is caused by a temperature change or the like. Even if the characteristics of the oscillator 24 fluctuate, the reference signal of the reference signal generator 10 can be maintained with high accuracy.
　 なお、複数の信号を高速で切り替える手法としては、ΔΣ変調部２３を用いることに限られず、例えばパルス幅変調（ＰＷＭ変調）を用いても良い。パルス幅変 調を用いる場合、パルス幅に応じて信号の出力時間を変化させることができるので、２つの信号の出力比率を簡単に制御することができる。 Note that the method of switching a plurality of signals at high speed is not limited to using the ΔΣ modulation unit 23, and for example, pulse width modulation (PWM modulation) may be used. When pulse width modulation is used, the signal output time can be changed in accordance with the pulse width, so that the output ratio of the two signals can be easily controlled.
　次に、図５を参照して、上記実施形態の変形例について説明する。本変形例の基準信号発生装置１０は、落雷や妨害電波等によってリファレンス信号を取得できなくなった場合であっても、所定の精度を維持しながら基準信号を送信する機能を有している。 Next, a modified example of the above embodiment will be described with reference to FIG. The reference signal generator 10 of the present modification has a function of transmitting the reference signal while maintaining a predetermined accuracy even when the reference signal cannot be acquired due to lightning strikes, jamming waves, or the like.
　 リングオシレータ２４の遅延素子５１は、電圧や温度の変化等により、遅延素子による遅延量が変化する。そのため、適切なリファレンス信号が得られない自走 状態においては、同一の制御信号でリングオシレータ２４を制御した場合においても、出力される信号の周波数が異なることがある。 The delay amount of the delay element 51 of the ring oscillator 24 changes due to a change in voltage or temperature. Therefore, in the self-running saddle state where an appropriate reference signal cannot be obtained, even when the ring oscillator 24 is controlled by the same control signal, the frequency of the output signal may be different.
　 本変形例の基準信号発生装置１０は、この特性によるズレ量を考慮することで、自走状態においても高精度な基準信号を出力し続けることができる。基準信号発 生装置１０は、この機能を発揮させるための構成として、図５に示すように、温度センサ（取得部）７１と、自走制御部７２と、特性記憶部７３と、スイッチ ７４と、を備える。 The reference signal generator 10 according to the present modification can continue to output a highly accurate reference signal even in a self-running state by considering the amount of deviation due to this characteristic. As shown in FIG. 5, the reference signal generating device 10 has a temperature sensor (acquisition unit) 71, a self-running control unit 72, a characteristic storage unit 73, and a switch rod 74 as a configuration for exhibiting this function. .
　温度センサ７１は、リングオシレータ２４の周囲の温度を検出するセンサである。温度センサ７１が検出した温度は、自走制御部７２へ出力される。 The temperature sensor 71 is a sensor that detects the temperature around the ring oscillator 24. The temperature detected by the temperature sensor 71 is output to the self-running control unit 72.
　 自走制御部７２は、同期状態である場合は、温度センサ７１が検出した温度と、リングオシレータ２４が出力した信号の周波数と、の対応関係（関連性）を特性 記憶部７３に記憶する。自走制御部７２は、特性記憶部７３に記憶した対応関係に基づいて遅延素子５１の温度変化特性を求める。また、自走制御部７２は、求 めた温度変化特性についても特性記憶部７３に記憶する。 The self-running control unit 72 stores the correspondence relationship (relevance) between the temperature detected by the temperature sensor 71 and the frequency of the signal output from the ring oscillator 24 in the characteristic storage unit 73 in the synchronous state. The self-running control unit 72 obtains the temperature change characteristic of the delay element 51 based on the correspondence stored in the characteristic storage unit 73. The self-running control unit 72 also stores the obtained temperature change characteristic in the characteristic storage unit 73.
　なお、遅延素子５１の温度変化特性は、基準信号発生装置１０を運用していないとき（例えば製品の出荷前）に求めることもできる。更には、製品の出荷前に求めた温度変化特性を、基準信号発生装置１０の運用中に取得したデータに基づいて修正することもできる。 Note that the temperature change characteristic of the delay element 51 can be obtained when the reference signal generator 10 is not operated (for example, before shipment of the product). Further, the temperature change characteristic obtained before the shipment of the product can be corrected based on data acquired during operation of the reference signal generator 10.
　また、自走制御部７２には、同期制御部２２が生成した制御信号が入力されている。自走制御部７２は、温度センサ７１が検出した現在の温度と、特性記憶部７３に記憶した温度変化特性と、を考慮して、この制御信号を補正する。 In addition, the control signal generated by the synchronization control unit 22 is input to the self-running control unit 72. The self-running control unit 72 corrects the control signal in consideration of the current temperature detected by the temperature sensor 71 and the temperature change characteristic stored in the characteristic storage unit 73.
　スイッチ７４には、同期制御部２２が出力する制御信号と、自走制御部７２が補正した制御信号と、が入力される。スイッチ７４は、ＧＰＳ受信部２１又は同期制御部２２等の指示に応じて、入力される２つの制御信号の何れか一方をリングオシレータ２４へ出力する。 The switch 74 receives a control signal output from the synchronization control unit 22 and a control signal corrected by the self-running control unit 72. The switch 74 outputs one of the two input control signals to the ring oscillator 24 in response to an instruction from the GPS receiving unit 21 or the synchronization control unit 22.
　 なお、ＧＰＳ受信部２１又は同期制御部２２等は、測位信号の演算結果等に基づいて、適切な測位信号を取得できているか否か、つまり、適切なリファレンス信 号を生成して利用できるか否かを判定可能である。ＧＰＳ受信部２１又は同期制御部２２等は、適切なリファレンス信号が利用できると判定した場合は、スイッ チ７４から、同期制御部２２が出力した制御信号をスイッチ７４に出力させる。 Whether the GPS receiver 21 or the synchronization control unit 22 can acquire an appropriate positioning signal based on the calculation result of the positioning signal, that is, whether an appropriate reference signal can be generated and used. It can be determined whether or not. When the GPS receiving unit 21 or the synchronization control unit 22 determines that an appropriate reference signal can be used, the switch 74 outputs the control signal output by the synchronization control unit 22 from the switch 74.
　一方、ＧＰＳ受信部２１又は同期制御部２２ 等は、適切なリファレンス信号が利用できないと判定した場合は、スイッチ７４から、自走制御部７２が出力した制御信号をスイッチ７４に出力させる。自走制 御部７２が出力する制御信号は、環境の変化（温度の変化等）を考慮して定められているので、自走状態において環境が変化した場合であっても、高精度な基準 信号を出力し続けることができる。なお、この場合は、リファレンス信号の精度が低いと考えられるので、同期制御部２２は、位相比較を行わない。 On the other hand, when it is determined that the appropriate reference signal is not available, the GPS receiving unit 21 or the synchronization control unit 22 causes the switch 74 to output the control signal output from the self-running control unit 72 from the switch 74. Since the control signal output from the self-running control unit 72 is determined in consideration of environmental changes (temperature changes, etc.), even if the environment changes in the self-running state, a highly accurate reference The signal can be continuously output. In this case, since the accuracy of the reference signal is considered low, the synchronization control unit 22 does not perform phase comparison.
　 上述のように、本願のリングオシレータ２４は周波数を詳細に設定することができるので、同期状態において、所望の周波数に精度良く合わせることができる。 従って、自走制御の開始時における周波数のズレを小さくすることができる。また、本願のリングオシレータ２４は周波数を詳細に設定することができるので、 自走状態においても、所望の周波数に精度良く合わせることができる。以上から、本変形例の基準信号発生装置１０は、従来と比較して、自走状態における周波 数のズレ量を抑えることができる。 As described above, since the ring oscillator 24 of the present application can set the frequency in detail, it can be accurately adjusted to the desired frequency in the synchronized state. Therefore, the frequency shift at the start of the self-running control can be reduced. In addition, since the ring oscillator 24 of the present application can set the frequency in detail, it can be accurately adjusted to a desired frequency even in the self-running state. From the above, the reference signal generator 10 of the present modification can suppress the frequency deviation amount in the self-running state as compared with the conventional case.
　以上に説明したように、本実施形態及び変形例の基準信号発生装置１０は、リングオシ レータ２４と、同期制御部２２と、ΔΣ変調部２３と、出力部４２，４３と、を備える。リングオシレータ２４は、ループ状の回路を有しており、当該回路を１ 周するときに通過する遅延素子５１の数を異ならせることで、出力する信号の周波数を調整可能である。同期制御部２２は、リファレンス信号と、リングオシ レータ２４が出力する信号又はそれに基づく信号と、を比較して比較結果を出力する（同期制御工程）。ΔΣ変調部２３は、同期制御部の比較結果に基づいて、 周波数が異なる複数の信号を切り替えながら出力するようにリングオシレータ２４を制御する（切替制御工程）。出力部４２，４３は、リングオシレータ２４が 出力した信号又はそれに基づく信号を出力する（出力工程）。以上により基準信号発生方法が実現される。 As described above, the reference signal generation device 10 of the present embodiment and the modification includes the ring oscillator 24, the synchronization control unit 22, the ΔΣ modulation unit 23, and the output units 42 and 43. The ring oscillator 24 has a loop-like circuit, and the frequency of the signal to be output can be adjusted by changing the number of delay elements 51 that pass through the circuit once. The synchronization control unit 22 compares the reference signal with a signal output from the ring oscillator 24 or a signal based thereon, and outputs a comparison result (synchronization control step). The ΔΣ modulator 23 controls the ring oscillator 24 based on the comparison result of the synchronization control unit so as to output a plurality of signals having different frequencies (switching control step). The output units 42 and 43 output a signal output from the ring oscillator 24 or a signal based thereon (output step). Thus, the reference signal generation method is realized.
　これにより、例えば周波数が異なる２つの信号を切り替えることで、基準信号の見かけの周波数を両信号の間の周波数とすることができる。従って、基準信号の周波数を遅延素子の１個の遅延量よりも細かく設定できるので、分解能を向上させることができる。 Thus, for example, by switching two signals having different frequencies, the apparent frequency of the reference signal can be set to a frequency between both signals. Accordingly, since the frequency of the reference signal can be set finer than the delay amount of one delay element, the resolution can be improved.
　以上に本発明の好適な実施の形態及び変形例を説明したが、上記の構成は例えば以下のように変更することができる。 The preferred embodiments and modifications of the present invention have been described above, but the above configuration can be modified as follows, for example.
　上記実施形態及び変形例では、２つの信号を切り替えながら出力する構成を開示したが、３つ以上の信号を切り替えながら出力する構成であっても良い。 In the above-described embodiment and modification, a configuration in which two signals are output while switching is disclosed, but a configuration in which three or more signals are output while switching may be employed.
　上記実施形態では、位相を比較する同期回路（ＰＬＬ回路）を備える構成であるが、代わりに周波数を比較する同期回路（ＦＬＬ回路）を備える構成であっても良い。 In the above embodiment, the configuration includes a synchronization circuit (PLL circuit) that compares phases, but a configuration that includes a synchronization circuit (FLL circuit) that compares frequencies instead may be used.
　 上記実施形態では、ＧＰＳアンテナ１１は、所定のケーブルを介して、同期制御部２２等が形成された基板と接続される構成である。これに代えて、この基板に ＧＰＳアンテナ１１が直接的に取り付けられる構成であっても良い。この場合、ケーブルが不要となるので、基準信号発生装置の設置コストを低減できる。 In the above embodiment, the GPS antenna 11 is connected to a substrate on which the synchronization control unit 22 and the like are formed via a predetermined cable. Instead, a configuration in which the ら れ る GPS antenna 11 is directly attached to the board may be employed. In this case, since no cable is required, the installation cost of the reference signal generator can be reduced.
　 上記実施形態及び変形例は、ＧＰＳ衛星からの信号に基づいてリファレンス信号を生成する構成であるが、ＧＮＳＳ（Ｇｌｏｂａｌ　Ｎａｖｉｇａｔｉｏｎ　 Ｓａｔｅｌｌｉｔｅ　Ｓｙｓｔｅｍ）を利用する構成であれば、適宜変更することができる。例えば、ＧＬＯＮＡＳＳ衛星やＧＡＬＩＬＥＯ衛星からの信号に基 づいてリファレンス信号を生成する構成に変更することができる。また、外部装置からのリファレンス信号を取得する構成としても良い。 Although the above embodiment and the modification are configured to generate a reference signal based on a signal from a GPS satellite, the configuration can be appropriately changed as long as the configuration uses GNSS (Global Navigation Satellite System). For example, the configuration can be changed to a configuration in which a reference signal is generated based on a signal from a GLONASS satellite or a GALILEO satellite. Further, it may be configured to acquire a reference signal from an external device.
　上記変形例では、リングオシレータ２４の周囲の温度を環境値として取得する構成であるが、これに代えて、例えばリングオシレータ２４の電圧を環境値として取得することもできる。 In the above modification, the ambient temperature of the ring oscillator 24 is acquired as an environmental value. Alternatively, for example, the voltage of the ring oscillator 24 can be acquired as the environmental value.
　ＧＰＳ受信部２１は、１ＰＰＳに代えて、ＰＰ２Ｓ等の１Ｈｚ以外の信号をリファレンス信号として生成する構成に変更することができる。また、ＧＰＳ受信部２１は、基準信号発生装置１０の内部ではなく外部に配置されていても良い。 The GPS receiving unit 21 can be changed to a configuration that generates a signal other than 1 Hz such as PP2S as a reference signal instead of 1PPS. Further, the GPS receiver 21 may be arranged outside the reference signal generator 10 instead of inside.
　基準信号発生装置１０が備える各部は、ハードウェアとして構成することに代えて、ソフトウェアにより構成することもできる。 The units included in the reference signal generation device 10 can be configured by software instead of being configured by hardware.
　１０　基準信号発生装置
　１１　ＧＰＳアンテナ
　２１　ＧＰＳ受信部
　２２　同期制御部
　２３　ΔΣ変調部（切替制御部）
　２４　リングオシレータ
　２５　分周部
　４１　入力部
　４２，４３　出力部 DESCRIPTION OF SYMBOLS 10 Reference signal generator 11 GPS antenna 21 GPS receiving part 22 Synchronization control part 23 ΔΣ modulation part (switching control part)
24 Ring oscillator 25 Dividing part 41 Input part 42, 43 Output part

Claims (7)

  1. 　ループ状の回路を有しており、当該回路を１周するときに通過する遅延素子の数を異ならせることで、出力する信号の周波数を調整可能なリングオシレータと、
    　リファレンス信号と、前記リングオシレータが出力する信号又はそれに基づく信号と、を比較して比較結果を出力する同期制御部と、
    　前記同期制御部の比較結果に基づいて、周波数が異なる複数の信号を切り替えながら出力するように前記リングオシレータを制御する切替制御部と、
    　前記リングオシレータが出力した信号又はそれに基づく信号を出力する出力部と、
    を備えることを特徴とする基準信号発生装置。     A ring oscillator that has a loop-shaped circuit and can adjust the frequency of a signal to be output by varying the number of delay elements that pass through the circuit once;
    A synchronization control unit that compares a reference signal with a signal output from the ring oscillator or a signal based thereon and outputs a comparison result;
    Based on the comparison result of the synchronization control unit, a switching control unit that controls the ring oscillator to output while switching a plurality of signals having different frequencies,
    An output unit for outputting a signal output from the ring oscillator or a signal based thereon; and
    A reference signal generation device comprising:
  2. 　請求項１に記載の基準信号発生装置であって、
    　前記切替制御部は、ΔΣ変調を用いて、周波数が異なる複数の信号を切り替えながら出力するように前記リングオシレータを制御することを特徴とする基準信号発生装置。     The reference signal generator according to claim 1,
    The reference signal generation device, wherein the switching control unit controls the ring oscillator so as to output a plurality of signals having different frequencies by using ΔΣ modulation.
  3. 　請求項１に記載の基準信号発生装置であって、
    　前記切替制御部は、パルス幅変調を用いて、周波数が異なる複数の信号を切り替えながら出力するように前記リングオシレータを制御することを特徴とする基準信号発生装置。     The reference signal generator according to claim 1,
    The switching control unit controls the ring oscillator so as to output a plurality of signals having different frequencies by switching using pulse width modulation.
  4. 　請求項２に記載の基準信号発生装置であって、
    　前記出力部が出力する信号には、周波数が異なる複数の信号が見かけ上、不規則に切り替わる部分が含まれることを特徴とする基準信号発生装置。     The reference signal generator according to claim 2,
    The signal output from the output unit includes a portion where a plurality of signals having different frequencies appear to be switched irregularly.
  5. 　請求項１から４までの何れか一項に記載の基準信号発生装置であって、
    　周波数が異なる複数の信号を切り替える時間間隔は、前記同期制御部が比較を行う時間間隔よりも短いことを特徴とする基準信号発生装置。     The reference signal generator according to any one of claims 1 to 4, wherein
    The reference signal generator according to claim 1, wherein a time interval for switching a plurality of signals having different frequencies is shorter than a time interval for the synchronization control unit to compare.
  6. 　請求項１から５までの何れか一項に記載の基準信号発生装置であって、
    　前記リングオシレータが使用される環境を示す環境値を取得する取得部と、
    　前記リングオシレータが出力する信号と前記環境値との関連性を求めて記憶する特性記憶部と、
    　適切なリファレンス信号が利用できるときは、前記特性記憶部が記憶する前記関連性に基づいて、制御信号を生成する自走制御部と、
    を備え、
    　前記切替制御部は、前記自走制御部が生成した制御信号に基づいて、周波数が異なる複数の信号を切り替えながら出力するように前記リングオシレータを制御することを特徴とする基準信号発生装置。     A reference signal generator according to any one of claims 1 to 5,
    An acquisition unit that acquires an environment value indicating an environment in which the ring oscillator is used;
    A characteristic storage unit for determining and storing the relationship between the signal output by the ring oscillator and the environmental value;
    When an appropriate reference signal is available, a self-running control unit that generates a control signal based on the association stored in the characteristic storage unit;
    With
    The reference signal generator according to claim 1, wherein the switching control unit controls the ring oscillator to output a plurality of signals having different frequencies based on a control signal generated by the self-running control unit.
  7. 　ループ状の回路を有しており、当該回路を１周するときに通過する遅延素子の数を異ならせることで、出力する信号の周波数を調整可能なリングオシレータを用いた基準信号発生方法において、
    　リファレンス信号と、前記リングオシレータが出力する信号又はそれに基づく信号と、を比較して比較結果を出力する同期制御工程と、
    　前記同期制御工程での比較結果に基づいて、周波数が異なる複数の信号を切り替えながら出力するように前記リングオシレータを制御する切替制御工程と、
    　前記リングオシレータが出力した信号又はそれに基づく信号を出力する出力工程と、
    を含むことを特徴とする基準信号発生方法。     In a reference signal generation method using a ring oscillator that has a loop-shaped circuit and can adjust the frequency of a signal to be output by changing the number of delay elements that pass through the circuit once.
    A synchronization control step of comparing a reference signal with a signal output from the ring oscillator or a signal based thereon and outputting a comparison result;
    Based on the comparison result in the synchronous control step, a switching control step for controlling the ring oscillator to output while switching a plurality of signals having different frequencies, and
    An output step of outputting a signal output from the ring oscillator or a signal based thereon;
    A method for generating a reference signal, comprising:
PCT/JP2017/001685 2016-03-01 2017-01-19 Reference signal generation device and reference signal generation method WO2017149978A1 (en)

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