CN101409556B - Control method and control circuit for passive hydrogen clock - Google Patents
Control method and control circuit for passive hydrogen clock Download PDFInfo
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- CN101409556B CN101409556B CN200710046964XA CN200710046964A CN101409556B CN 101409556 B CN101409556 B CN 101409556B CN 200710046964X A CN200710046964X A CN 200710046964XA CN 200710046964 A CN200710046964 A CN 200710046964A CN 101409556 B CN101409556 B CN 101409556B
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Abstract
The invention discloses a control method for a passive hydrogen clock and a control circuit thereof. The microwave probing signals of a crystal oscillator loop and a cavity loop are fed in a microwave cavity in a time-sharing way; in the crystal oscillator loop, the frequency of a 10MHz crystal oscillator is locked at the spectral line of hydrogen maser; in the cavity loop, the frequency of the microwave cavity is locked at the 10MHz crystal oscillator; two microwave signals with different frequencies which are respectively arranged at the two sides of the center frequency of the transition spectrum line of the hydrogen atom and at the two sides of the center frequency of a microwave cavity response curve are fed in the microwave cavity alternately; the strength of two adjacent half period detecting signals which are given under the interaction of a microwave field and the hydrogen atom is compared, and the magnitude of deviation is used for changing the control quantity of the crystal oscillator so as to lock the frequency of the crystal oscillator; the strength of two adjacent half period detecting signals under the interaction of the microwave field and the microwave cavity response curve is compared, and the magnitude of deviation is used for changing the voltage control quantity located at an variable capacitance diode in the microwave cavity to lock the frequency of the microwave cavity at the 10MHz crystal oscillator.
Description
Technical field
The invention belongs to the atomic frequency standard field, specifically, is a kind of control method and control circuit that is used for passive hydrogen clock.
Background technology
Along with global position system plays more and more important effect in fields such as national science and technology, military affairs, industry, so the research of hydrogen atomic clock also just becomes more and more urgent.Hydrogen atomic clock is a kind of high precision time and frequency standard, and its every performance all is very outstanding, all has important effect in fundamental research, navigation, radar, geodesic survey, astronomical observation and the communications field.
Hydrogen atomic clock is a kind of atomic frequency standard based on the hydrogen atom transition, and its jump frequency is greatly about 1.4GHz.Existing passive hydrogen clock is a kind of non-self-excitation type atomic oscillator, because the loaded quality factor of microwave cavity is lower, hydrogen maer can not self-oscillation, and needing the extraneous detectable signal that injects could operate as normal.Two frequency-locked loop are arranged: crystal oscillator loop and cavity loop in the control circuit of passive hydrogen clock.The hydrogen atom jump frequency is in order to the frequency of control crystal oscillator in the quantized system, and the pulling effect that change to produce for microwave cavity resonance frequency in the amount of cancellation subsystem also needs to come controlled microwave chamber frequency with crystal oscillator frequency.
Ubiquitous two kinds of modulation systems are single-frequency modulation system and double frequency modulation system at present.In single-frequency modulation system commonly used, adopting a modulating frequency to produce detectable signal is injected in the microwave cavity, after process and the microwave cavity effect, utilize the absorption and the chromatic dispersion principle of atom to isolate crystal oscillator and the two-part error signal of cavity, crystal oscillator and cavity are locked by comparison error signal.This mode has been widely used in the passive-type Hydrogen Atom Frequency Standard, but in any case the inventor finds that this modulation system all can't avoid interfering with each other between crystal oscillator and the cavity loop.Thereby this interference can produce the stability that amplitude and phase noise influence atomic frequency standard, and in addition, the error signal that wants accurately to separate crystal oscillator and cavity is also had higher requirement to the realization of circuit.In the double frequency modulation system, simultaneously the two-way detectable signal is injected in the microwave cavity, respectively with hydrogen atom transition spectral line and chamber curve effect, produce crystal oscillator and the two-part error signal of cavity, the inventor finds that this modulation system also can't avoid interfering with each other between crystal oscillator and the cavity loop fully.
Summary of the invention
The object of the present invention is to provide a kind of control method and control circuit that is used for passive hydrogen clock, eliminating and to reduce unfavorable factor in single-frequency modulation system and the double frequency modulation system, thereby provide performance higher time and frequency standard.
In order to achieve the above object, technical scheme of the present invention is as follows:
A kind of control method that is used for passive hydrogen clock comprises the steps: in the crystal oscillator loop, with the frequency lock of 10MHz crystal oscillator on the spectral line of hydrogen maer; In the cavity loop, with the frequency lock of resonant cavity on the crystal oscillator of 10MHz; Two high accuracies, be symmetrically distributed in the microwave signal of hydrogen atom transition core frequency both sides different frequency, alternately be fed in the microwave cavity, under microwave field and hydrogen atom interaction, provided the detection signal of two adjacent half periods, by these two signal strength signal intensities of direct comparison, its measures of dispersion locks the frequency of crystal oscillator in order to the controlled quentity controlled variable that changes crystal oscillator; Two high accuracies, be symmetrically distributed in the microwave signal of microwave cavity response center of curve frequency both sides different frequency, alternately be fed in the microwave cavity, under microwave field and the interaction of microwave cavity response curve, provided the detection signal of two adjacent half periods, by these two signal strength signal intensities of direct comparison, its measures of dispersion makes the microwave cavity frequency lock on the 10MHz crystal oscillator in order to the voltage control quantity that change is seated on the variable capacitance diode in the microwave cavity.In order to eliminate and to reduce interfering with each other between crystal oscillator loop and the cavity loop, the microwave sounding signal of crystal oscillator loop and cavity loop is that timesharing is fed in the microwave cavity.
Correspondingly, a kind of control circuit of realizing above-mentioned control method comprises that detectable signal produces circuit and signal processing circuit; Described detectable signal produces circuit and comprises: pulse signal generator receives a clock signal and generates rate signal, modulation signal and blanking signal; The Frequency Hopping Signal generator receives described clock signal and from the modulation signal of pulse signal generator; Switch receives from the rate signal of pulse signal generator and from the output signal of Frequency Hopping Signal generator; The frequency frequency multiplier receives described clock signal; The output signal of the output signal of described switch and frequency frequency multiplier obtains detectable signal after mixing, periodically deliver to microwave cavity; Described signal processing circuit comprises: oscillator; Envelope detector receives through the detectable signal of amplification with from the mixed intermediate-freuqncy signal that zooms into of the signal of oscillator; Split circuit receives output signal and described rate signal from envelope detector, extracts error detection signal; Digital servo circuit receives described blanking signal, rate signal and from the error detection signal of split circuit, the virtual voltage controlled quentity controlled variable that calculates is sent to the 10MHz crystal oscillator and is seated on the voltage-controlled end of variable capacitance diode on the microwave cavity.
Adopt above-mentioned novel control method and control circuit, owing to use timesharing double frequency modulation system, control the microwave cavity frequency and the crystal oscillator frequency of hydrogen clock respectively, adopt existing relatively single-frequency modulation system of special like this control mode and double frequency modulation system, can reduce the mutual interference mutually of cavity loop and crystal oscillator loop, improve the frequency stability of hydrogen clock.
Description of drawings
Fig. 1 is the schematic diagram of hyperfine energy levels of hydrogen atom ground state and magnetic field intensity relation;
Fig. 2 is a hydrogen Amplifier Based On Stimulated Emission Of Radiation schematic diagram;
Fig. 3 is a passive-type hydrogen atomic clock electronic system block diagram;
Fig. 4 is the control circuit working timing figure;
Fig. 5 is a switch synthesizer theory diagram;
Fig. 6 is that detectable signal acts on hydrogen atom transition spectral line schematic diagram.
Embodiment
According to Fig. 1 to Fig. 6, provide preferred embodiment of the present invention, and described in detail below, enable to understand better function of the present invention, characteristics.
The operation principle of passive hydrogen clock at first is described.The passive-type hydrogen atomic clock is a kind of non-self-excitation type atomic oscillator, because the loaded quality factor in chamber is lower, hydrogen maer can not self-oscillation, and needing the extraneous pumping signal of injecting is the microwave sounding signal.Two transition between energy level frequencies in the frequency of microwave sounding signal and the hyperfine splitting of hydrogen atom ground state are very approaching, its effect is equivalent to perturbation, excite the hydrogen atom that is in energy level to transit to down energy level, realize stable stimulated emission, the maser oscillator of this moment just is equivalent to an arrowband microwave amplifier.
Generally in the passive-type hydrogen atomic oscillator, we are the F=1 that utilize in the hydrogen atom ground state hyperfine splitting energy level, m
F=0 attitude is to F=0, m
FThe σ transition of=0 attitude, as shown in Figure 1.Because it is very fast that the σ jump frequency of hydrogen atom response curve changes with external magnetic field, only need very weak magnetic field just can work, thereby can reduce the error that magnetic field causes.
Fig. 2 is a hydrogen Amplifier Based On Stimulated Emission Of Radiation fundamental diagram.Hydrogen molecule dissociates into hydrogen atom under the rf electric field effect, inject vacuum chamber and form atomic beam through jet, enters state selection magnet, and it will go up energy level (F=1, m
F=0) atom focuses on and stores in the bubble mouthful, and energy level (F=0, m down
F=0) atom is opened partially.Store bubble and be placed on the position suitable in the resonant cavity, the stimulated radiation transition takes place in last level atom and intracavitary irradiation field interactions, stores bubble and handles through special coating, makes atom and bubble wall carry out a large amount of collisions and its energy state of unlikely change.Like this, last level atom just can be long-time and radiation field interact, make width change very narrow of stimulated emission spectral line.
The formation of passive-type hydrogen atomic clock electronic system as shown in Figure 3.Two frequency-locked loop are arranged: crystal oscillator loop and cavity loop among the figure.The jump frequency of hydrogen atom is in order to the frequency of control crystal oscillator in the hydrogen maer, and the pulling effect that change to produce for microwave cavity resonance frequency in the amount of cancellation subsystem also needs to come control chamber frequently with crystal oscillator frequency.The frequency of 10MHz crystal oscillator is locked on the spectral line of hydrogen maer in the crystal oscillator loop; In the cavity loop, the frequency of resonant cavity is locked on the crystal oscillator of 10MHz.Adopted the i.e. square-wave frequency modulation form at a slow speed of frequency-shift keying technology in the system, promptly two high accuracies, be symmetrically distributed in the microwave signal of hydrogen atom transition core frequency both sides different frequency, alternately be fed in the microwave cavity, under microwave field and hydrogen atom interaction, provided the detection signal of two adjacent half periods, by these two signal strength signal intensities of direct comparison, its measures of dispersion locks the frequency of crystal oscillator in order to the controlled quentity controlled variable that changes crystal oscillator; Equally two high accuracies, be symmetrically distributed in the microwave signal of microwave cavity response center of curve frequency both sides different frequency, alternately be fed in the microwave cavity, under microwave field and the interaction of microwave cavity response curve, provided the detection signal of two adjacent half periods, by these two signal strength signal intensities of direct comparison, its measures of dispersion makes the microwave cavity frequency lock on the 10MHz crystal oscillator in order to the voltage control quantity that change is seated on the variable capacitance diode in the microwave cavity.
According to Fig. 3 as can be known, electronic system is divided into detectable signal and produces circuit and signal processing circuit, and detectable signal produces circuit and mainly contains 10MHz crystal oscillator, pulse signal generator, the first switch synthesizer, second switch synthesizer, frequency frequency multiplier, switch etc.Signal processing circuit is made up of local oscillator, envelope detector, split circuit, digital servo circuit.
The output of 10MHz crystal oscillator enters pulse signal generator as clock signal, produces output 1, output 2 and exports 3, and its sequential chart as shown in Figure 4.Output 1 (rate signal): the periodic signal of certain duty ratio is provided, is used for switching to cavity loop and crystal oscillator loop microwave excitation.Output 2 (modulation signals): the frequency dividing ratio of the change switch synthesizer of this signal period property makes the output frequency of switch synthesizer at f
1To f
2Between saltus step.Output 3 (blanking signals): as synchronizing signal control servo system Acquisition Error signal, very strong disturbing pulse in the signal when removing frequency inverted simultaneously.The generation reason of disturbing pulse: can there be certain hour in hydrogen atom in storing bubble, after the frequency inverted, be in the hydrogen atom that stores in the bubble and be in suddenly in the microwave field of new frequency, cause the part of atoms energy state to change, thereby produce a big disturbing pulse in the output of detector.
The first switch synthesizer and second switch synthesizer replace output frequency respectively under the control of the modulation signal of the output 2 of pulse signal generator be the signal of 20.405M ± 50KHz and 20.405M ± 1.25Hz, theory diagram as shown in Figure 5, k is the divide ratio in the switch synthesizer feedback control loop.The switch synthesizer adopts the 20.405751MHz ± f of digital phase discriminator to voltage controlled oscillator output in the synthesizer
mSignal frequency split after 2.5MHz and 10MHz signal four frequency divisions of crystal oscillator carry out phase demodulation to the frequency of 2.5MHz.As shown in Figure 5: digital phase discriminator is operated in 2.5MHz, and the switch synthesizer changes divide ratio k periodically under the control of modulation signal, thereby alternately output frequency is 20.405751MHz+f
mAnd 20.405751MHz-f
mSignal, f wherein
mBe the frequency modulation amplitude of system, f in crystal oscillator loop and cavity loop
mBe different values, its size depends on the bandwidth of hydrogen atom transition spectral line and microwave cavity response curve.The f of the first switch synthesizer in native system
m=1.25Hz, the f of second switch synthesizer
m=50KHz.
In addition, the first switch synthesizer and second switch synthesizer also can be replaced by a Direct Digital Frequency Synthesizers (DDS), reduce the circuit complexity.Concrete realization be by 89C52 type single-chip microcomputer under the control of rate signal, to the register timesharing in the AD9852 type DDS chip insert the control number, and modulation signal is received the FSK input of DDS chip, the Frequency Hopping Signal that just can the output of timesharing ground needs of DDS like this.
In Fig. 3, the output of 10MHz crystal oscillator is the signal of 1.4GHz through overfrequency frequency multiplier output frequency.The output of the first switch synthesizer, second switch synthesizer and the output 1 of pulse signal generator is as the input of switch, promptly switch under rate signal control alternately output frequency be the signal of 20.405M ± 50KHz and 20.405M ± 1.25Hz.The output of the output of switch and frequency frequency multiplier is sent to frequency mixer and is obtained the detectable signal that frequency approaches 1.42GHz, and wherein 1.42GHz ± 50KHz is as the detectable signal of cavity loop, and 1.42GHz ± 1.25Hz is as the detectable signal of crystal oscillator loop.The output of frequency mixer by variable attenuator under the effect of pulse signal generator output 1 respectively with the different coefficient restriction crystal oscillator detectable signals and the power of cavity detectable signal, in the hope of reaching Optimum Excitation power.Crystal oscillator detectable signal and cavity detectable signal periodically are injected in the microwave cavity, and interacting with hydrogen atom transition spectral line and chamber curve obtains containing the detection signal of control information down.Amplifier receives and the amplification detection signal, detection signal after the amplification and oscillator are (for the harmonic wave that reduces the 10MHz crystal oscillator and the synchronous interference of 20.405MHz signal, local oscillator employing sound surface oscillation device freely produces the signal of 1.44GHz) output to be sent to the frequency that mixer amplifier obtains through amplifying be the intermediate-freuqncy signal of 19MHz.This intermediate-freuqncy signal is passed through envelope detector, and then will export by split circuit, under output 1 effect of pulse signal generator, extracts the error detection signal of crystal oscillator loop and cavity loop.Error detection signal is sent into digital servo circuit respectively, pass through the synchronous of pulse signal generator output 3, servo circuit is gathered the detection signal of adjacent two half periods, relatively the difference of detection signal obtains error signal, exports to crystal oscillator respectively and is seated on the voltage-controlled end of the variable capacitance diode on the microwave cavity in order to the locking hydrogen atomic clock by calculating the virtual voltage controlled quentity controlled variable.
The operating process of whole system is: behind the servo system electrification reset, master control chip DSP (TMS320LF2407) waits for that the trailing edge of blanking signal arrives, when the blanking signal trailing edge arrives, the DSP response external is interrupted, output by built-in spi bus sends the Serial Control word to AD converter AD7321, and the input of spi bus receives the result after last AD changes simultaneously, and the data that read are counted, when count value reaches the value that needs, the forward and backward half period detected value that reads is carried out mean filter, finish data read at last.DSP is after having read AD data converted and mean filter, the value of flag bit flag2 is added 1, and judge whether to reach 2, if satisfy then show that the data of current sampling are the value in later half cycle, then the value in preceding half period and later half cycle is subtracted each other as the first-order error input variable; If the value of flag bit flag2 does not reach 2, illustrate that then current sampled data is the value of preceding half period, then with the storage of the value of preceding half period and wait for that the arrival of blanking signal next time gathers the input variable in later half cycle.
DSP is after obtaining the first-order error signal, catch rate signal by the capture interrupt pin in built-in EV (task manager) module, when the trailing edge of rate signal or rising edge came, DSP responded capture interrupt, and this moment is with the flag bit set of cavity (crystal oscillator).For example, the flag bit initial value is flag1=1 (crystal oscillator is effective), the trailing edge of response ratio signal at first, enter behind the interrupt routine flag bit set flag1=0 (cavity is effective), change simultaneously and catch the feasible rising edge of next time then catching rate signal of polarity, when rising edge arrives, again with flag bit flag1=1 (crystal oscillator is effective), and then catch the trailing edge of rate signal next time, so just can be periodically the error signal of cavity and crystal oscillator be read.Value by judgement symbol position flag1 alternately sends the error signal that transmission control word control AD7321 gathers cavity or crystal oscillator to AD7321 in the external interrupt of blanking signal.
Because the breadth of spectrum line of Hydrogen Atom Frequency Standard is very narrow, general width has only several hertz, exceeds this scope, just can not obtain the error signal of system, thereby also just can't lock.Therefore the starting point of initialization crystal oscillator search voltage at first after system reset, being DSP is set at an initial value with the output of the digital regulation resistance in the servo system, thereby after this increase progressively the control voltage of the output increase crystal oscillator of DA transducer DAC7641 according to the step-length of setting at every turn, scope is-Umv-+Umv, when the output of DAC7641 goes beyond the scope, then with its zero setting, output with digital regulation resistance simultaneously increases Vmv, carry out the search of the next one-Umv-+Umv, progressively search for the voltage-controlled scope of crystal oscillator, till finding keyed end, the output of digital regulation resistance at this moment is fixed on a value and remains unchanged.The condition of judging keyed end is that the integrated value of error signal reduces 4 times continuously.
In addition, because the crystal oscillator error signal only could occur near keyed end, the absolute value that has added error signal when therefore judging whether to reach keyed end again must be greater than the condition of a specific value, must satisfy these two conditions simultaneously and just can think and really entered keyed end.Avoided like this crystal oscillator is locked in the outer spurious lock phenomenon of Hydrogen Atom Frequency Standard spectral line.
If in once pre-locked voltage search procedure, can not satisfy required condition, then the crystal oscillator voltage controling value can increase progressively always, when the value of controlled quentity controlled variable exceeds certain value, so just the controlled quentity controlled variable with crystal oscillator resets into initial value, the magnitude of voltage that guarantees pre-search is in effective range, carry out the operation of a pre-search again, till finding keyed end.
Pre-locked process promptly enters normal lock-out state after finishing, and this moment, DSP was with the control voltage that calculates crystal oscillator resonant cavity variable capacitance diode of error amount through pid control algorithm, and final output locking crystal oscillator and chamber are frequently.In whole process, come latch well frequently according to control algolithm in the cavity loop cycle always.In addition, the very important point is in order to reduce interfering with each other between cavity loop and the crystal oscillator loop, and in each conversion place in cavity and crystal oscillator cycle, DSP gives up the preceding margin of error several times, crystal oscillator and variable capacitance diode is not revised.
At last frequency discrimination principle (crystal oscillator loop) is once illustrated.
In passive-type hydrogen atomic clock system, hydrogen atom transition spectral line plays the effect of frequency discriminator.The detectable signal that is sent to microwave cavity is at f
1With f
2Between in by square-wave frequency modulation, as shown in Figure 6, frequency f
1With f
2Be symmetrically distributed in hyperfine transition frequency .f
0Both sides.
We define:
F in the formula
aBe 10MHz crystal oscillator output frequency, M is the multiplier parameter of synthesizer.The purpose of crystal oscillator loop makes following formula set up exactly:
Mf
a＝f
0 (2)
Also promptly:
f
0-f
1＝f
2-f
0 (3)
We define:
f
1＝f
i+f
m (4)
f
2＝f
i-f
m (5)
F wherein
iBe detectable signal, f
mBe the frequency modulation amplitude.Here T
mBe the cycle of square-wave modulation signal, if T
mGreater than atom and the microwave field interaction time (T that adopts in the experiment
mBe 1s, be about 150ms by measuring the interaction time), response curve intensity (the interactional power of detectable signal and atomic resonance) b so
sReaching its steady-state value in half period separately.If b
s (1)And b
s (2)Be the response of two half periods, and f
i-f
oVery little, we obtain:
Through the error signal after amplification, mixing, detection, the demodulation be:
K ' is a constant in the formula, with fundamental factor, and the coupling coefficient of coupling loop, the electronic circuit gain is relevant.
Demodulation function is:
If the frequency f of resonant cavity
cBe transferred on the atom resonance frequency, that is:
f
c＝f
0 (10)
Again because b
sAnd partial derivative
Be respectively frequency shift (FS) f-f
0Even function and odd function, so, can obtain error signal from (6), (7), (8):
This shows, for a given frequency shift (FS) f
i-f
oWork as f
o-f
mAnd f
o+ f
mBe positioned at the flex point time error signal amplitude maximum of quantum response curve.Error signal d
1Through after the processing of servo system, be added on the voltage-controlled end of crystal oscillator, make d
1=0.Cavity loop and crystal oscillator loop are similar.
The front provides the description to preferred embodiment, so that any technical staff in this area can use or utilize the present invention.To this preferred embodiment, those skilled in the art can make various modifications or conversion on the basis that does not break away from the principle of the invention.Should be appreciated that these modifications or conversion do not break away from protection scope of the present invention.
Claims (10)
1. control method that is used for passive hydrogen clock, the microwave sounding signal of crystal oscillator loop and cavity loop are that timesharing is fed in the microwave cavity; This method comprises the steps:
In the crystal oscillator loop, with the frequency lock of 10MHz crystal oscillator on the spectral line of hydrogen maer;
In the cavity loop, with the frequency lock of microwave cavity on the crystal oscillator of 10MHz;
Two high accuracies, be symmetrically distributed in the microwave signal of hydrogen atom transition core frequency both sides different frequency, alternately be fed in the microwave cavity, under microwave field and hydrogen atom interaction, provided the detection signal of two adjacent half periods, by these two signal strength signal intensities of direct comparison, its measures of dispersion locks the frequency of crystal oscillator in order to the controlled quentity controlled variable that changes crystal oscillator as the crystal oscillator error signal;
Two high accuracies, be symmetrically distributed in the microwave signal of microwave cavity response curve centre frequency both sides different frequency, alternately be fed in the microwave cavity, under microwave field and the interaction of microwave cavity response curve, provided the detection signal of two adjacent half periods, by these two signal strength signal intensities of direct comparison, the voltage control quantity that its measures of dispersion is used for changing as the cavity error signal on the variable capacitance diode that is seated in the microwave cavity makes the microwave cavity frequency lock on the 10MHz crystal oscillator.
2. a kind of control method that is used for passive hydrogen clock as claimed in claim 1, it is characterized in that, described crystal oscillator error signal and cavity error signal are passed through the control voltage that control algolithm calculates crystal oscillator and microwave cavity variable capacitance diode, the frequency of final output locking crystal oscillator and microwave cavity; In whole process, 's the frequency that locks microwave cavity according to control algolithm in the cavity loop cycle always, and the crystal oscillator loop cycle is wanted earlier through locking according to control algolithm after the pre-locked process again, each conversion place in cavity loop cycle and crystal oscillator loop cycle, preceding crystal oscillator error signal and cavity error signal several times given up, crystal oscillator and variable capacitance diode are not revised.
3. realize the control circuit of method as claimed in claim 1 or 2 for one kind, it is characterized in that, comprise that detectable signal produces circuit and signal processing circuit;
Described detectable signal produces circuit and comprises:
Pulse signal generator receives a clock signal and generates rate signal, modulation signal and blanking signal;
The Frequency Hopping Signal generator receives described clock signal and from the modulation signal of pulse signal generator;
Switch receives from the rate signal of pulse signal generator and from the output signal of Frequency Hopping Signal generator;
The frequency frequency multiplier receives described clock signal;
The output signal of the output signal of described switch and frequency frequency multiplier obtains detectable signal after mixing, periodically deliver to microwave cavity;
Described signal processing circuit comprises:
Local oscillator;
Envelope detector receives through the detectable signal of amplification with from the mixed intermediate-freuqncy signal that zooms into of the signal of local oscillator;
Split circuit receives output signal and described rate signal from envelope detector, extracts error detection signal;
Digital servo circuit receives described blanking signal, rate signal and from the error detection signal of split circuit, the virtual voltage controlled quentity controlled variable that calculates is sent to the 10MHz crystal oscillator and is seated on the voltage-controlled end of variable capacitance diode on the microwave cavity.
4. a kind of control circuit that is used for passive hydrogen clock as claimed in claim 3 is characterized in that described clock signal is produced by a 10MHz crystal oscillator, and this 10MHz crystal oscillator receives described virtual voltage controlled quentity controlled variable.
5. a kind of control circuit that is used for passive hydrogen clock as claimed in claim 4 is characterized in that, described Frequency Hopping Signal generator is two switch synthesizers, and it is 20.405751MHz+f that these two switch synthesizers all replace output frequency
mAnd 20.405751MHz-f
mSignal, f wherein
mBe the frequency modulation amplitude of system, f in crystal oscillator loop and cavity loop
mBe different values, its size depends on the bandwidth of hydrogen atom transition spectral line and microwave cavity response curve.
6. a kind of control circuit that is used for passive hydrogen clock as claimed in claim 5 is characterized in that described switch synthesizer comprises digital phase discriminator, loop filter and voltage controlled oscillator; Digital phase discriminator is to the 20.405751MHz ± f of voltage controlled oscillator output
mSignal frequency split after 2.5MHz and the 10MHz signal frequency split of atomic clock carry out phase demodulation to the frequency of 2.5MHz; Described switch synthesizer changes divide ratio periodically under the control of square-wave modulation signal, thereby alternately output frequency is 20.405751MHz+f
mAnd 20.405751MHz-f
mSignal.
7. a kind of control circuit that is used for passive hydrogen clock as claimed in claim 4 is characterized in that, described Frequency Hopping Signal generator comprises a Direct Digital Frequency Synthesizers and a single-chip microcomputer; Described single-chip microcomputer under the control of rate signal, to the register timesharing in the Direct Digital Frequency Synthesizers chip insert the control number, and modulation signal is received the FSK input of Direct Digital Frequency Synthesizers chip.
8. a kind of control circuit that is used for passive hydrogen clock as claimed in claim 7 is characterized in that, described single-chip microcomputer is a 89C52 type single-chip microcomputer, and described Direct Digital Frequency Synthesizers is an AD9852 type Direct Digital Frequency Synthesizers.
9. a kind of control circuit that is used for passive hydrogen clock as claimed in claim 3 is characterized in that this control circuit also comprises a variable attenuator, and this variable attenuator receives described rate signal; Described detectable signal is periodically delivered to microwave cavity again through behind this variable attenuator.
10. as the described a kind of control circuit that is used for passive hydrogen clock of arbitrary claim in the claim 4 to 8, it is characterized in that this control circuit also comprises a variable attenuator, this variable attenuator receives described rate signal; Described detectable signal is periodically delivered to microwave cavity again through behind this variable attenuator.
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| CN101727067B (en) * | 2009-12-02 | 2011-04-27 | 东南大学 | Intelligent control algorithm used for passive hydrogen clock |
| JP5954540B2 (en) * | 2012-09-10 | 2016-07-20 | セイコーエプソン株式会社 | Atomic cell module, quantum interference device, electronic device, and magnetic field control method for atomic cell |
| CN103077799B (en) * | 2012-12-05 | 2015-06-03 | 东南大学 | Passive hydrogen clock ultra-uniform C-field magnetic cylinder and manufacturing method thereof |
| CN104579340B (en) * | 2015-02-04 | 2018-01-30 | 上海航天测控通信研究所 | A kind of passive hydrogen clock digital servosystem based on FPGA |
| CN109324498A (en) * | 2018-09-30 | 2019-02-12 | 中国科学院上海天文台 | A kind of atomic state state selection system of hydrogen atomic clock |
| CN111884653B (en) * | 2020-06-08 | 2022-06-24 | 北京无线电计量测试研究所 | Device and method for stabilizing microwave cavity frequency of integrating sphere cold atomic clock |
| CN112286106B (en) * | 2020-10-30 | 2022-02-18 | 上海航天测控通信研究所 | Detection signal universal generating device for microwave atomic clock |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5714910A (en) * | 1994-12-19 | 1998-02-03 | Efratom Time And Frequency Products, Inc. | Methods and apparatus for digital frequency generation in atomic frequency standards |
| CN1591243A (en) * | 2003-09-03 | 2005-03-09 | 美国迅腾有限公司 | Light stabilization for an optically excitable atomic medium |
| CN100495926C (en) * | 2004-11-30 | 2009-06-03 | 中国科学院武汉物理与数学研究所 | Dominance combination method in passive atomic frequency standard system and its device |
-
2007
- 2007-10-11 CN CN200710046964XA patent/CN101409556B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5714910A (en) * | 1994-12-19 | 1998-02-03 | Efratom Time And Frequency Products, Inc. | Methods and apparatus for digital frequency generation in atomic frequency standards |
| CN1591243A (en) * | 2003-09-03 | 2005-03-09 | 美国迅腾有限公司 | Light stabilization for an optically excitable atomic medium |
| CN100495926C (en) * | 2004-11-30 | 2009-06-03 | 中国科学院武汉物理与数学研究所 | Dominance combination method in passive atomic frequency standard system and its device |
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| CN101409556A (en) | 2009-04-15 |
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