CN103293376B - A kind of measuring method of frequency stability and device - Google Patents
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Abstract
The invention discloses a kind of frequency stability measurement method and apparatus, belong to electronic technology field.Described method comprises carries out frequency inverted to the output signal in measured signal source, obtains first frequency signal; With the first reference signal for reference signal, and set multiple as Measurement bandwidth with first frequency signal frequency, measure the frequency of first frequency signal; Adopt the frequency of first frequency signal, according to the short-term frequency stability in first variance formulae discovery measured signal source; Frequency inverted is carried out to the output signal in measured signal source, obtains second frequency signal; With the second reference signal for reference signal, measure the frequency of second frequency signal; Adopt the frequency of second frequency signal, according to the long-term stability in second variance formulae discovery measured signal source.The present invention, by when measuring short-term frequency stability, controls the Measurement bandwidth of count measurement, improves the accuracy measuring short-term frequency stability.
Description
Technical field
The present invention relates to electronic technology field, particularly a kind of measuring method of frequency stability and device.
Background technology
Along with the high speed development of modern society, the application of split-second precision frequency technique is more and more extensive, and the stability requirement that people export the temporal frequency of clock source is also more and more higher.Usually, the stability of clock source adopts frequency stability to weigh.
The measuring method of existing a kind of survey frequency degree of stability, the method comprises: carry out scaling down processing to the output signal in measured signal source; In setting-up time, the pulse number of the output signal in the measured signal source after reference signal and frequency division is counted; The frequency of measured signal is calculated according to pulse number; According to the frequency of the output signal in measured signal source and the normalized form of frequency stability, calculate the frequency stability in measured signal source.
Realizing in process of the present invention, inventor finds that prior art at least exists following problem:
Usually standard variance formula is adopted to calculate the frequency stability of signal source in prior art; but; find after deliberation; a signal source has two Stability indexes usually; these two Stability indexes are respectively short-term frequency stability and long-term frequency stability; wherein; what short-term frequency stability characterized is the jitter level of signal; what long-term frequency stability characterized is signal frequency drift degree in time; therefore, the performance adopting single frequency stability in prior art to weigh a signal source is not accurate enough.
Summary of the invention
Adopting single frequency stability to weigh the not accurate enough problem of the performance of a signal source to solve prior art, embodiments providing a kind of measuring method and device of frequency stability.Described technical scheme is as follows:
On the one hand, embodiments provide a kind of measuring method of frequency stability, described method comprises:
Frequency inverted is carried out to the output signal in measured signal source, obtains first frequency signal;
With the first reference signal for reference signal, and set multiple as Measurement bandwidth with described first frequency signal frequency, measure the frequency of described first frequency signal;
Adopt the frequency of described first frequency signal, determine the short-term frequency stability in described measured signal source according to first variance formula;
Frequency inverted is carried out to the output signal in described measured signal source, obtains second frequency signal;
With the second reference signal for reference signal, measure the frequency of described second frequency signal;
Adopt the frequency of described second frequency signal, determine the long-term frequency stability in described measured signal source according to second variance formula;
Described with the first reference signal for reference signal, and set multiple as Measurement bandwidth with described first frequency signal frequency, measure the frequency of described first frequency signal, comprising:
Carry out low-pass filtering to described first frequency signal, filtering bandwidth is Measurement bandwidth;
With the first reference signal for time-base signal, measure the pulse number of filtered described first frequency signal within the given time;
Frequency according to first frequency signal described in following formulae discovery:
F＝1/(T/N)；
Wherein, F is the frequency of described first frequency signal, and T is the described given time, and N is the pulse number of the filtered described first frequency signal recorded;
Described with the second reference signal for reference signal, measure the frequency of described second frequency signal, comprising:
The instantaneous phase gathering described second frequency signal and the second reference signal is poor, obtains the digital signal representing the change of described phase differential;
Integration is carried out to described digital signal, obtains d. c. voltage signal;
Analog to digital conversion is carried out to described d. c. voltage signal, obtains the phase differential of described second frequency signal and described second reference signal;
According to described phase differential and described second reference signal, determine the frequency of described second frequency signal.
Alternatively, described setting multiple is 1-5 times.
Preferably, described first variance formula is Allan variance formula, and described second variance formula is Hadamard Variance formula.
On the other hand, embodiments provide a kind of measurement mechanism of frequency stability, described device comprises:
For carrying out frequency inverted to the output signal in measured signal source, obtain the first frequency modular converter of first frequency signal;
For carrying out frequency inverted to the output signal in described measured signal source, obtain the second frequency modular converter of second frequency signal;
For with the first reference signal for reference signal, set multiple as Measurement bandwidth with the frequency of described first frequency signal, measure the first measurement module of the frequency of the first frequency signal that described first frequency modular converter obtains;
For with the second reference signal for reference signal, measure second measurement module of frequency of the described second frequency signal that described second frequency modular converter obtains; And
The frequency of the described first frequency signal recorded for adopting described first measurement module, the short-term frequency stability in described measured signal source is determined according to first variance formula, the frequency of the described second frequency signal adopting described second measurement module to record, determines the processing module of the long-term frequency stability in described measured signal source according to second variance formula;
Described first frequency modular converter is electrically connected with described first measurement module, described processing module respectively, described second frequency modular converter is electrically connected with described second measurement module, described processing module respectively, and described processing module is electrically connected with described first measurement module, described second measurement module respectively;
Described first measurement module is used for,
Carry out low-pass filtering to described first frequency signal, filtering bandwidth is Measurement bandwidth;
With the first reference signal for time-base signal, measure the pulse number of filtered described first frequency signal within the given time;
Frequency according to first frequency signal described in following formulae discovery:
F＝1/(T/N)；
Wherein, F is the frequency of described first frequency signal, and T is the described given time, and N is the pulse number of the filtered described first frequency signal recorded;
Described second measurement module comprises:
For gathering the phase differential collecting unit of the instantaneous phase difference of described second frequency signal and the second reference signal;
For carrying out integration to digital signal, obtain the integrating circuit of d. c. voltage signal, described digital signal is that described processing module obtains according to the instantaneous phase difference of described second frequency signal and the second reference signal;
For carrying out analog to digital conversion to described d. c. voltage signal, obtain the AD conversion unit of the phase differential of described second frequency signal and described second reference signal;
Correspondingly, described processing module is used for,
The described phase differential obtained according to described AD conversion unit and described second reference signal, determine the frequency of described second frequency signal.
Alternatively, described setting multiple is 1-5 times.
Alternatively, described first frequency modular converter and described second frequency modular converter are same module.
Alternatively, described device also comprises for providing the first signal source of described first reference signal and for providing the secondary signal source of described second reference signal, described first signal source is electrically connected with described first frequency modular converter, described first measurement module respectively, and the first signal source is crystal oscillator; Described secondary signal source is electrically connected with described second frequency modular converter, described second measurement module respectively, and secondary signal source is atomic clock.
Preferably, described first variance formula is Allan variance formula, and described second variance formula is Hadamard Variance formula.
The beneficial effect that the technical scheme that the embodiment of the present invention provides is brought is:
By measuring respectively the short-term frequency stability in measured signal source and long-term frequency stability, adopt two frequency stabilities to weigh the performance of a signal source, accuracy is high.
Accompanying drawing explanation
In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, below the accompanying drawing used required in describing embodiment is briefly described, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is the process flow diagram of the measuring method of a kind of frequency stability that the embodiment of the present invention one provides;
Fig. 2 is process flow diagram measured signal being carried out to frequency inverted that the embodiment of the present invention one provides;
Fig. 3 is process flow diagram second frequency signal and the 3rd reference signal being carried out to phase compare that the embodiment of the present invention one provides;
Fig. 4 is the graph of a relation of the Measurement bandwidth that provides of the embodiment of the present invention and frequency stability;
Fig. 5 is the structural representation of the measurement mechanism of a kind of frequency stability that the embodiment of the present invention two provides;
Fig. 6 is the structural representation of the frequency translation module that the embodiment of the present invention two provides;
Fig. 7 is the structural representation of the phase compare module that the embodiment of the present invention two provides.
Embodiment
For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, embodiment of the present invention is described further in detail.
Embodiment one
Embodiments provide a kind of measuring method of frequency stability, see Fig. 1, the method comprises:
Step 101: carry out frequency inverted to the output signal in measured signal source, obtains first frequency signal.
By frequency inverted, the output signal in measured signal source can be converted to low frequency signal, be convenient to measure.Meanwhile, the frequency range in the measured signal source that the embodiment of the present invention can be made to be suitable for is wider.
In this step 101, when frequency inverted is carried out to the output signal in measured signal source, the output signal (the first reference signal as in the embodiment of the present invention) of the clock source (such as VCXO) that short-term frequency stability is high can be adopted as time-base signal, the output signal (the second reference signal as in the embodiment of the present invention) of the clock source (such as atomic clock) that long-term frequency stability are high also can be adopted as time-base signal.
Particularly, see Fig. 2, this step 101 can comprise:
Step 1011: with the first reference signal or the second reference signal for time-base signal, carry out count measurement to the output signal in measured signal source, obtains the frequency of the output signal in measured signal source.
More specifically, this step 1011 comprises:
With the first reference signal or the second reference signal for time-base signal, measure the pulse number of the output signal in measured signal source within the given time, and calculate the frequency of measured signal according to following formula (1):
F＝1/(T/N)(1)；
Wherein, F is the frequency of the output signal in measured signal source, and T is the given time, and N is the pulse number of the output signal in the measured signal source recorded.
Step 1012: according to the frequency of the output signal in measured signal source, produce the 3rd frequency signal, the frequency of the 3rd frequency signal is integer frequency immediate with the frequency of the output signal in measured signal source.
In the present embodiment, this integer frequency can with MHz (megahertz) for unit.
Step 1013: carry out frequency multiplication to the 3rd frequency signal, obtains first frequency signal.
Step 102: with the first reference signal for reference signal, and set multiple as Measurement bandwidth with first frequency signal frequency, measure the frequency of first frequency signal.
Wherein, Measurement bandwidth is the scope of the frequency of the first frequency signal that can measure, Measurement bandwidth is that the setting multiple of first frequency signal frequency represents and only measures the signal within the scope of the setting multiple of first frequency signal frequency, equipment multiple as Measurement bandwidth is 5, then at most only the quintuple harmonics of first frequency signal is measured, the part being equivalent to first frequency signal intermediate frequency rate to be greater than quintuple harmonics has carried out filtering, improves the accuracy of measurement.
Particularly, the scope setting multiple can be 1-5 times.
Preferably, the scope setting multiple is generally 1 times, 2.5 times or 5 times.For example, if first frequency signal frequency is 1KHz (KHz), so Measurement bandwidth can be 1KHz, 2.5KHz or 5KHz.
Particularly, this step 102 can comprise: carry out low-pass filtering to the first signal, and filtering bandwidth is this Measurement bandwidth; With the first reference signal for time-base signal, measure the pulse number of the output signal in measured signal source within the given time, and calculate the frequency of measured signal according to formula (1).
Step 103: the frequency adopting first frequency signal, according to the short-term frequency stability in first variance formulae discovery measured signal source.
Alternatively, first variance formula can be Allan variance formula, and Allan variance formula (2) is as follows:
Wherein, σ
yfor Allan variance value, τ is sampling period and sampling time, f
hfor the higher cutoff frequency of signal source, N is number of samples,
y is the relative frequency deviation of each sampling time output frequency, and f0 is the frequency of reference signal, f
ifor the frequency of the output signal in measured signal source.
Step 104: carry out frequency inverted to the output signal in measured signal source, obtains second frequency signal.
In this step 104, when frequency inverted is carried out to the output signal in measured signal source, the output signal (the first reference signal as in the embodiment of the present invention) of the clock source (such as VCXO) that short-term frequency stability is high can be adopted as time-base signal, the output signal (the second reference signal as in the embodiment of the present invention) of the clock source (such as atomic clock) that long-term frequency stability are high also can be adopted as time-base signal.
Particularly, this step 104 can comprise: with the first reference signal or the second reference signal for time-base signal, carry out count measurement to the output signal in measured signal source, obtains the output signal frequency in measured signal source; According to the frequency of the output signal in measured signal source, produce the 4th frequency signal, the frequency of the 4th frequency signal is integer frequency immediate with the frequency of the output signal in measured signal source; Frequency multiplication is carried out to the 4th frequency signal, produces second frequency signal.
Step 105: with the second reference signal for reference signal, measures the frequency of second frequency signal.
Particularly, see Fig. 3, this step 105 comprises:
Step 1051: the instantaneous phase gathering second frequency signal and the 3rd reference signal is poor, obtains the digital signal representing phase differential change.
Preferably, the collection of the instantaneous phase difference to second frequency signal and the 3rd reference signal can be triggered with the rising edge of signal.
Alternatively, digital signal is the digital square-wave of the phase differential change representing second frequency signal and the 3rd reference signal.
Step 1052: carry out integration to digital signal, obtains d. c. voltage signal.
Step 1053: analog to digital conversion is carried out to d. c. voltage signal, obtain second frequency signal and the 3rd reference signal phase differential.
Step 1054: according to phase differential and the 3rd reference signal, obtains the frequency of second frequency signal.
Step 106: the frequency adopting second frequency signal, according to the long-term stability in second variance formulae discovery measured signal source.
Particularly, second variance formula can be Allan variance formula, also can be Hadamard Variance formula; Be preferably Hadamard Variance formula, Hadamard Variance formula (3) is as follows:
Wherein, H σ
yfor Hadamard Variance value, τ is the sampling time, and m is number of samples, y
kfor the relative frequency deviation of output frequency.
In Hadamard Variance formula (3), y
k+2-2*y
k+1+ y
k=(y
k+2-y
k+1)-(y
k+1-y
k), due to previous bracket (y
k+2-y
k+1) in include the impact of frequency drift on frequency stability, a rear bracket (y
k+1-y
k) in also include the impact of frequency drift, therefore previous bracket and a rear bracket subtract each other, and can eliminate the impact of frequency drift on frequency stability.
Simply introduce the relation of Measurement bandwidth and frequency stability below in conjunction with Fig. 4, as shown in Figure 4, what the longitudinal axis represented is degree of stability, and what transverse axis represented is the sampling time, and three curves in figure are frequency stability measured under different Measurement bandwidths respectively.As shown in Figure 1, when the sampling time is less than 1s, frequency stability is relevant with Measurement bandwidth, and when being greater than 1s when employed, frequency stability is basic and Measurement bandwidth is irrelevant.During owing to carrying out short-term frequency stability measurement, the employing time is generally less than 1s, when carrying out long-term frequency stability measurement, the employing time is generally greater than 1s, the embodiment of the present invention is when carrying out short-term frequency stability and measuring, and carried out bandwidth control, the frequency stability accuracy therefore recorded is high.
The embodiment of the present invention is by measuring respectively the short-term frequency stability in measured signal source and long-term frequency stability, and adopt two frequency stabilities to weigh the performance of a signal source, accuracy is high.And when measuring short-term frequency stability, Measurement bandwidth being controlled, take into account the relation between short-term frequency stability and Measurement bandwidth, improve the accuracy measuring short-term frequency stability.
Embodiment two
Embodiments provide a kind of measurement mechanism of frequency stability, see Fig. 5, this device comprises first frequency modular converter 1, second frequency modular converter 2, first measurement module 3, second measurement module 4 and processing module 5.First frequency modular converter 1, for carrying out frequency inverted to the output signal in measured signal source, obtains first frequency signal.Second frequency modular converter 2, for carrying out frequency inverted to the output signal in measured signal source, obtains second frequency signal.First measurement module 3 for the first reference signal for reference signal, set multiple as Measurement bandwidth with the frequency of first frequency signal, measure the frequency of the first frequency signal that first frequency modular converter 1 obtains.Second measurement module 4 for second frequency signal for reference signal, measure the frequency of the second frequency signal that second frequency modular converter 2 obtains.The frequency of first frequency signal of processing module 5 for adopting the first measurement module 3 and recording, according to the short-term frequency stability in first variance formula determination measured signal source, the frequency of the second frequency signal adopting the second measurement module to record, according to the long-term frequency stability in second variance formula determination measured signal source.
Wherein, first frequency modular converter 1 is electrically connected with the first measurement module 3, processing module 5 respectively, second frequency modular converter 2 is electrically connected with the second measurement module 4, processing module 5 respectively, and processing module 5 is electrically connected with the first measurement module 3, second measurement module 4 respectively.
Alternatively, this setting multiple can be 1-5 times.
Alternatively, first frequency modular converter 1 and second frequency modular converter 2 can be same module.
Alternatively, this device can also comprise the first signal source for providing the first reference signal, and the first signal source is electrically connected with first frequency modular converter 1, first measurement module 3 respectively.
Particularly, the first signal source can be crystal oscillator.
Alternatively, this device can also comprise the secondary signal source for providing the second reference signal, and secondary signal source is electrically connected with second frequency modular converter 2, second measurement module 4 respectively.
Particularly, secondary signal source can be atomic clock, as hydrogen atomic clock, rubidium atomic clock or cesium-beam atomic clock.
Preferably, this device can also comprise for carrying out frequency division to the second reference signal, obtains the DDS (DirectDigitalSynthesizer, Direct Digital Synthesizer) of the 3rd reference signal.
Particularly, processing module 5 can comprise central processing unit, single-chip microcomputer, microcontroller or microprocessor.
Particularly, see Fig. 6, counting unit 11, DDS12 and PLL (PhaseLockedLoop, phaselocked loop) 13 when first frequency modular converter 1 comprises walking.When walking counting unit 11 for the first reference signal or the second reference signal for reference signal, count measurement is carried out to the output signal in measured signal source, obtains the frequency of the output signal in measured signal source.DDS12 is used under the control of control module 5, and produce the 3rd frequency signal, the frequency of the 3rd frequency signal is the immediate integer frequency of frequency of the output signal in the measured signal source obtained with counting unit when walking 11.The 3rd frequency signal that PLL13 is used for DDS12 produces carries out frequency multiplication, produces first frequency signal.When walking, counting unit 11 is electrically connected with DDS12 by processing module 5.PLL13 is electrically connected with DDS12, processing module 5 respectively.
More specifically, DDS12 obtain the frequency of frequency signal and the frequency multiplication ratio of PLL13 controlled by processing module 5.Processing module 5 can by sending command control word to DDS12, rewrite the internal frequency register of DDS12, make DDS12 output frequency be the frequency signal of the immediate integer of measured signal frequency obtained with counting unit when walking 11, command control word is that the measured signal frequency that processing module 5 obtains according to counting unit when walking 11 obtains.During as walked, counting unit 11 obtains the frequency of measured signal is 11.0592MHz, it is 11MHz that processing module 5 obtains with the immediate integer of frequency according to this frequency, processing module 5 sends the command control word corresponding with 11MHz to DDS12, rewrite the internal frequency register of DDS12, made DDS12 output frequency be the frequency signal of 11MHz.PLL13, according to the frequency multiplication ratio of processing module 5, carries out frequency multiplication to the frequency signal of 11MHz, obtains the frequency signal of required frequency, as the frequency signal of 1KHz.
Correspondingly, counting unit 21, DDS22 and PLL23 when first frequency modular converter 2 comprises walking.When walking counting unit 21 for the first reference signal or the second reference signal for reference signal, count measurement is carried out to the output signal in measured signal source, obtains the frequency of the output signal in measured signal source.DDS22 is used under the control of control module 5, and produce the 4th frequency signal, the frequency of the 4th frequency signal is the immediate integer frequency of frequency of the output signal in the measured signal source recorded with counting unit when walking 21.The 4th frequency signal that PLL23 is used for DDS22 produces carries out frequency multiplication, produces second frequency signal.When walking, counting unit 21 is electrically connected with DDS22 by processing module 5.PLL23 is electrically connected with DDS22, processing module 5 respectively.
Particularly, see Fig. 7, the second measurement module 4 comprises phase differential collecting unit 41, integrating circuit 42 and AD conversion unit 43.Phase differential collecting unit 41 for gather the instantaneous phase difference of second frequency signal and the 3rd reference signal phase differential collecting unit 41, for carrying out integration to digital signal, the acquisition integrating circuit 42 of d. c. voltage signal and the d. c. voltage signal for obtaining integrating circuit 42 carry out analog to digital conversion, obtain the AD conversion unit 43 of the phase differential of second frequency signal and the 3rd reference signal.Phase acquisition unit 41 is electrically connected with second frequency modular converter 2.Phase acquisition unit 41 is electrically connected with integrating circuit 42 by processing module 5.Integrating circuit 42 and AD conversion unit 43 are electrically connected.AD conversion unit 43 is electrically connected with processing module 5.
Wherein, digital signal is that processing module 5 obtains according to the instantaneous phase difference of second frequency signal and the 3rd reference signal.
Correspondingly, processing module 5 for, according to AD conversion unit 3 obtain phase differential and the 3rd reference signal, determine the frequency of second frequency signal.
The embodiment of the present invention is by measuring respectively the short-term frequency stability in measured signal source and long-term frequency stability, and adopt two frequency stabilities to weigh the performance of a signal source, accuracy is high.And when measuring short-term frequency stability, Measurement bandwidth being controlled, take into account the relation between short-term frequency stability and Measurement bandwidth, improve the accuracy measuring short-term frequency stability.
The invention described above embodiment sequence number, just to describing, does not represent the quality of embodiment.
The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (8)
1. a measuring method for frequency stability, is characterized in that, described method comprises:
Frequency inverted is carried out to the output signal in measured signal source, obtains first frequency signal;
With the first reference signal for reference signal, and set multiple as Measurement bandwidth with described first frequency signal frequency, measure the frequency of described first frequency signal;
Adopt the frequency of described first frequency signal, determine the short-term frequency stability in described measured signal source according to first variance formula;
Frequency inverted is carried out to the output signal in described measured signal source, obtains second frequency signal;
With the second reference signal for reference signal, measure the frequency of described second frequency signal;
Adopt the frequency of described second frequency signal, determine the long-term frequency stability in described measured signal source according to second variance formula;
Described with the first reference signal for reference signal, and set multiple as Measurement bandwidth with described first frequency signal frequency, measure the frequency of described first frequency signal, comprising:
Carry out low-pass filtering to described first frequency signal, filtering bandwidth is Measurement bandwidth;
With the first reference signal for time-base signal, measure the pulse number of filtered described first frequency signal within the given time;
Frequency according to first frequency signal described in following formulae discovery:
F＝1/(T/N)；
Wherein, F is the frequency of described first frequency signal, and T is the described given time, and N is the pulse number of the filtered described first frequency signal recorded;
Described with the second reference signal for reference signal, measure the frequency of described second frequency signal, comprising:
The instantaneous phase gathering described second frequency signal and the second reference signal is poor, obtains the digital signal representing the change of described phase differential;
Integration is carried out to described digital signal, obtains d. c. voltage signal;
Analog to digital conversion is carried out to described d. c. voltage signal, obtains the phase differential of described second frequency signal and described second reference signal;
According to described phase differential and described second reference signal, determine the frequency of described second frequency signal.
2. method according to claim 1, is characterized in that, described setting multiple is 1-5 times.
3. method according to claim 1 and 2, is characterized in that, described first variance formula is Allan variance formula, and described second variance formula is Hadamard Variance formula.
4. a measurement mechanism for frequency stability, is characterized in that, described device comprises:
For carrying out frequency inverted to the output signal in measured signal source, obtain the first frequency modular converter of first frequency signal;
For carrying out frequency inverted to the output signal in described measured signal source, obtain the second frequency modular converter of second frequency signal;
For with the first reference signal for reference signal, set multiple as Measurement bandwidth with the frequency of described first frequency signal, measure the first measurement module of the frequency of the first frequency signal that described first frequency modular converter obtains;
For with the second reference signal for reference signal, measure second measurement module of frequency of the described second frequency signal that described second frequency modular converter obtains; And
The frequency of the described first frequency signal recorded for adopting described first measurement module, the short-term frequency stability in described measured signal source is determined according to first variance formula, the frequency of the described second frequency signal adopting described second measurement module to record, determines the processing module of the long-term frequency stability in described measured signal source according to second variance formula;
Described first frequency modular converter is electrically connected with described first measurement module, described processing module respectively, described second frequency modular converter is electrically connected with described second measurement module, described processing module respectively, and described processing module is electrically connected with described first measurement module, described second measurement module respectively;
Described first measurement module is used for,
Carry out low-pass filtering to described first frequency signal, filtering bandwidth is Measurement bandwidth;
With the first reference signal for time-base signal, measure the pulse number of filtered described first frequency signal within the given time;
Frequency according to first frequency signal described in following formulae discovery:
F＝1/(T/N)；
Wherein, F is the frequency of described first frequency signal, and T is the described given time, and N is the pulse number of the filtered described first frequency signal recorded;
Described second measurement module comprises:
For gathering the phase differential collecting unit of the instantaneous phase difference of described second frequency signal and the second reference signal;
For carrying out integration to digital signal, obtain the integrating circuit of d. c. voltage signal, described digital signal is that described processing module obtains according to the instantaneous phase difference of described second frequency signal and the second reference signal;
For carrying out analog to digital conversion to described d. c. voltage signal, obtain the AD conversion unit of the phase differential of described second frequency signal and described second reference signal;
Correspondingly, described processing module is used for,
The described phase differential obtained according to described AD conversion unit and described second reference signal, determine the frequency of described second frequency signal.
5. device according to claim 4, is characterized in that, described setting multiple is 1-5 times.
6. device according to claim 4, is characterized in that, described first frequency modular converter and described second frequency modular converter are same module.
7. the device according to any one of claim 4-6, it is characterized in that, described device also comprises for providing the first signal source of described first reference signal and for providing the secondary signal source of described second reference signal, described first signal source is electrically connected with described first frequency modular converter, described first measurement module respectively, and the first signal source is crystal oscillator; Described secondary signal source is electrically connected with described second frequency modular converter, described second measurement module respectively, and secondary signal source is atomic clock.
8. the device according to any one of claim 4-6, is characterized in that, described first variance formula is Allan variance formula, and described second variance formula is Hadamard Variance formula.
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| CN103472330B (en) * | 2013-09-13 | 2015-11-04 | 北京无线电计量测试研究所 | A kind of measurement mechanism of frequency stability of superconduction frequency stabilization oscillator |
| CN103575982B (en) * | 2013-10-28 | 2016-01-20 | 中国科学院国家授时中心 | A kind of real-time frequency Analysis on Stability method |
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