CN101183124A - System and method for measuring tiny frequency deviation - Google Patents
System and method for measuring tiny frequency deviation Download PDFInfo
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- CN101183124A CN101183124A CNA2007101947530A CN200710194753A CN101183124A CN 101183124 A CN101183124 A CN 101183124A CN A2007101947530 A CNA2007101947530 A CN A2007101947530A CN 200710194753 A CN200710194753 A CN 200710194753A CN 101183124 A CN101183124 A CN 101183124A
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- frequency measurement
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Abstract
The present invention discloses a system for measuring a minimal frequency error, which comprises two frequency amplification modules, a frequency mixer, a low-pass filter, a waveform transformation module and a frequency measurement module. A method using the system for measuring the minimal error comprises the steps as follows: a first frequency amplification module and a second frequency amplification module respectively send a reference signal and a signal to be measured to the frequency mixer after taking frequency amplification; the frequency mixer sends a signal obtained through frequency mixing and down conversion after the reference signal and the signal to be measured are amplified to the low-pass filter; the low-pass filter filters out a intermediate-frequency signal and sends to the waveform transformation module; the waveform transformation module transforms the filtered out intermediate-frequency signal to a digital signal and exports to the frequency measurement module; the frequency measurement module conducts frequency measurement to the digital signal and the minimal frequency error is obtained. The present invention can conducts quick and high definition frequency measurement to the minimal frequency error.
Description
Technical field
The present invention relates to measuring technique, relate in particular to a kind of system and method for measuring tiny frequency deviation.
Background technology
The use of high precision clock makes to the accuracy requirement of clock measurement more and more higher.Traditional survey frequency method has two kinds of frequency counting method and cycle chronometries.The frequency counting method is in a regular time cycle of measured signal to be counted, and this counting is proportional to signal frequency, and the method is applicable to the measurement of upper frequency; The cycle chronometry is that one of measured signal or fixing several cycles are carried out timing, and this time is inversely proportional to the frequency of measured signal, and the method is applicable to the measurement of low frequency signal.
In actual use, we need use some frequency standard signals (is the signal of 5M, 10M as frequency) through regular meeting, but because technical restriction, and often the frequency of the signal that is produced by signal generator all has certain little deviation with the required standard value.Because this value is very little, so the user is difficult to use above-mentioned two kinds of classic methods to measure the exact value of this deviation.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of system and method for measuring tiny frequency deviation.
The technical solution used in the present invention is:
The invention provides a kind of system of measuring tiny frequency deviation, comprising: two frequency amplification modules, frequency mixer, low-pass filter, waveform transformation module and frequency measurement modules;
First, second frequency amplification module is respectively applied for reference signal and measured signal is carried out sending to described frequency mixer after frequency is amplified;
Described frequency mixer is used for and will sends to described low-pass filter behind the signal that down coversion obtains after described reference signal after amplifying and the measured signal mixing;
Described low-pass filter sends to described waveform transformation module after being used for intermediate-freuqncy signal leached;
Described waveform transformation module is exported to described frequency measurement module after being used for converting the described intermediate-freuqncy signal that leaches to digital signal;
Described frequency measurement module obtains described tiny frequency deviation after being used for described digital signal measured.
Further, described frequency measurement module as sampling clock, is carried out frequency measurement to described digital signal with described reference signal.
Further, described system also comprises the 3rd frequency amplification module, and it is used for and will sends to described frequency measurement module after the described reference signal amplification; The reference signal of described frequency measurement module after with described amplification carried out frequency measurement as sampling clock to described digital signal.
Further, described frequency measurement module is the field programmable gate array module.
Further, described first, second frequency amplification module is respectively two frequency synthesizers, and it is used for described reference signal and measured signal are amplified integral multiple or non-integral multiple respectively.
Further, described the 3rd frequency amplification module is a frequency multiplier, and it is used for described reference signal is amplified integral multiple.
The present invention also provides a kind of method that said system is measured tiny frequency deviation of using, and may further comprise the steps:
A, first, second frequency amplification module carry out reference signal and measured signal to send to frequency mixer after frequency is amplified respectively;
Send to low-pass filter behind the signal that down coversion obtains after described reference signal after b, described frequency mixer will amplify and the measured signal mixing;
C, described low-pass filter send to the waveform transformation module after intermediate-freuqncy signal is leached;
D, described waveform transformation module are exported to the frequency measurement module after converting the described intermediate-freuqncy signal that leaches to digital signal;
E, described frequency measurement module are carried out frequency measurement to described digital signal, obtain described tiny frequency deviation.
Further, among the step e, described frequency measurement module as sampling clock, is carried out frequency measurement to described digital signal with described reference signal.
Further, among the step e, described frequency measurement module uses reference signal after the 3rd frequency amplification module amplifies as sampling clock, and described digital signal is carried out frequency measurement.
Further, among the step a, described first, second frequency amplification module is respectively two frequency synthesizers, and it amplifies integral multiple or non-integral multiple respectively with described reference signal and measured signal.
Compared with prior art, pull-in frequency synthesizer of the present invention is to reference frequency and treat that measured frequency all carries out frequency multiplication, also frequency departure is amplified simultaneously.On the frequency selection purposes of frequency multiplication, choose different frequency multiplication values again, like this, just produced the intermediate-freuqncy signal of the frequency departure that comprises amplification after the mixing, make the low-pass filter of back level be easy to this intermediate-freuqncy signal is leached.The method of this introducing intermediate frequency mixing has guaranteed on the one hand frequency departure is amplified, and the intermediate-freuqncy signal after the conversion is leached easily, avoids the interference of high order component after the mixing, has improved realizability.
In addition, the present invention also uses FPGA (Field Programmable Gate Array, field programmable gate array) module is as the frequency measurement module, use the reference frequency after the frequency multiplication as sample frequency, can realize the tiny frequency deviation signal that has amplified is carried out quick, high-precision frequency measurement.
Description of drawings
Fig. 1 is a system architecture synoptic diagram of measuring tiny frequency deviation in the embodiment of the invention;
Fig. 2 is a structural representation of measuring two constant-temperature crystal oscillator (OCXO) system for use in carrying in the embodiment of the invention.
Embodiment
Below in conjunction with drawings and Examples technical scheme of the present invention is described in detail.
As shown in Figure 1, the system of measuring tiny frequency deviation comprises: two frequency synthesizers, frequency mixer, low-pass filter, waveform transformation module, frequency multiplier, frequency measurement module (can be the FPGA module, but be not limited to adopt this module).
Wherein:
Frequency synthesizer 1,2 is respectively applied for reference signal and measured signal is carried out sending to frequency mixer after frequency is amplified, and has amplified frequency departure thus;
Frequency mixer is used for reference signal and measured signal mixing after amplifying, and down coversion obtains comprising the intermediate-freuqncy signal of the frequency departure of amplification, sends to low-pass filter again;
After leaching, the intermediate-freuqncy signal that low-pass filter is used for comprising the frequency departure of amplification sends to the waveform transformation module;
The waveform transformation module is used for converting the intermediate-freuqncy signal of simulation to digital signal, and sends to the frequency measurement module;
Frequency multiplier is used for giving the reference signal frequency multiplication frequency measurement module as work clock;
The frequency measurement module is used for according to frequency counting method of the prior art and cycle chronometry the digital signal that receives being carried out frequency measurement, thereby calculates tiny frequency deviation.
If reference frequency is f
0, treat that measured frequency is f
0+ Δ f then utilizes the present invention to measure the step of tiny frequency deviation Δ f, comprising:
Steps A, amplify reference frequency f respectively with frequency synthesizer 1,2
0With frequency f to be measured
0+ Δ f is to k
0* f
0And k
1* (f
0+ Δ f), wherein, k
0＞0, k
1＞0, and k
0≠ k
1With frequency multiplier with reference frequency f
0Frequency multiplication is to k
2* f
0After, make sampling clock for the frequency measurement module, wherein, k
2Be positive integer.Also can directly use f
0As sampling clock;
Reference frequency after step B, frequency mixer will amplify and treat the measured frequency mixing after the signal that obtains of down coversion send to low-pass filter;
Step C, low-pass filter are with intermediate-freuqncy signal k
1* (f
0+ Δ f)-k
0* f
0Send to the waveform transformation module after leaching; Because the introducing of intrinsic intermediate frequency is convenient to low-pass filter the undesired signal that the higher hamonic wave difference frequency produces is leached;
Step D, waveform transformation module are with above-mentioned intermediate-freuqncy signal k
1* (f
0+ Δ f)-k
0* f
0Become the discernible digital signal of logic, be input to the frequency measurement module;
Step e, frequency measurement module f
0Or the k after the frequency multiplication
2* f
0Make sampling clock, to comprising the intermediate-freuqncy signal k of amplification frequency deviation
1* (f
0+ Δ f)-k
0* f
0Carry out frequency measurement, obtain Δ f.
By said method as can be seen, increase the frequency multiplication multiple k of frequency multiplier
2With increase frequency synthesizer k
0, k
1Can improve the precision of frequency deviation measurement, therefore, in actual applications, the selection of these three values should be with reference to concrete accuracy requirement.
Further be illustrated with an application example of the present invention below.
When measuring the frequency departure of two constant-temperature crystal oscillators (OCXO), its theory diagram as shown in Figure 2.Owing to need measure the frequency departure of OCXO module to be measured under difference control voltage, so on the existing systems basis, increased by two parts of single-chip microcomputer and analog-digital chip again.Reference signal (being the frequency standard signal) is exported by caesium clock.By selecting suitable k
0, k
1And k
2Value can go out the little deviation value of OCXO crystal output frequency and reference frequency under difference control voltage at 1 second build-in test, and measuring accuracy can reach 1e
-10With the different control voltage of Single-chip Controlling analog-digital chip output, from the frequency measurement module, read the frequency departure that test obtains again and be shown to the user, then can measure OCXO crystal output frequency and whether satisfy index request.
Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection domain of the appended claim of the present invention.
Claims (10)
1. a system of measuring tiny frequency deviation is characterized in that, comprising: two frequency amplification modules, frequency mixer, low-pass filter, waveform transformation module and frequency measurement modules;
First, second frequency amplification module is respectively applied for reference signal and measured signal is carried out sending to described frequency mixer after frequency is amplified;
Described frequency mixer is used for and will sends to described low-pass filter behind the signal that down coversion obtains after described reference signal after amplifying and the measured signal mixing;
Described low-pass filter sends to described waveform transformation module after being used for intermediate-freuqncy signal leached;
Described waveform transformation module is exported to described frequency measurement module after being used for converting the described intermediate-freuqncy signal that leaches to digital signal;
Described frequency measurement module obtains described tiny frequency deviation after being used for described digital signal measured.
2. the system as claimed in claim 1 is characterized in that,
Described frequency measurement module as sampling clock, is carried out frequency measurement to described digital signal with described reference signal.
3. the system as claimed in claim 1 is characterized in that,
Described system also comprises the 3rd frequency amplification module, and it is used for and will sends to described frequency measurement module after the described reference signal amplification; The reference signal of described frequency measurement module after with described amplification carried out frequency measurement as sampling clock to described digital signal.
4. as claim 1,2 or 3 described systems, it is characterized in that,
Described frequency measurement module is the field programmable gate array module.
5. the system as claimed in claim 1 is characterized in that,
Described first, second frequency amplification module is respectively two frequency synthesizers, and it is used for described reference signal and measured signal are amplified integral multiple or non-integral multiple respectively.
6. system as claimed in claim 3 is characterized in that,
Described the 3rd frequency amplification module is a frequency multiplier, and it is used for described reference signal is amplified integral multiple.
7. an application rights requires the method for 1 described systematic survey tiny frequency deviation, it is characterized in that, may further comprise the steps:
A, first, second frequency amplification module carry out reference signal and measured signal to send to frequency mixer after frequency is amplified respectively;
Send to low-pass filter behind the signal that down coversion obtains after described reference signal after b, described frequency mixer will amplify and the measured signal mixing;
C, described low-pass filter send to the waveform transformation module after intermediate-freuqncy signal is leached;
D, described waveform transformation module are exported to the frequency measurement module after converting the described intermediate-freuqncy signal that leaches to digital signal;
E, described frequency measurement module are carried out frequency measurement to described digital signal, obtain described tiny frequency deviation.
8. method as claimed in claim 7 is characterized in that,
Among the step e, described frequency measurement module as sampling clock, is carried out frequency measurement to described digital signal with described reference signal.
9. method as claimed in claim 7 is characterized in that,
Among the step e, described frequency measurement module uses reference signal after the 3rd frequency amplification module amplifies as sampling clock, and described digital signal is carried out frequency measurement.
10. method as claimed in claim 7 is characterized in that,
Among the step a, described first, second frequency amplification module is respectively two frequency synthesizers, and it amplifies integral multiple or non-integral multiple respectively with described reference signal and measured signal.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2007101947530A CN100567998C (en) | 2007-12-03 | 2007-12-03 | A kind of system and method for measuring tiny frequency deviation |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2007101947530A CN100567998C (en) | 2007-12-03 | 2007-12-03 | A kind of system and method for measuring tiny frequency deviation |
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|---|---|
| CN101183124A true CN101183124A (en) | 2008-05-21 |
| CN100567998C CN100567998C (en) | 2009-12-09 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101458279B (en) * | 2008-12-09 | 2010-11-03 | 中国科学院国家授时中心 | Frequency measurement method by beat method capable of enhancing precision |
| CN106059575A (en) * | 2016-05-23 | 2016-10-26 | 中国舰船研究设计中心 | Boat-carrying information system frequency standard calibrating device and calibrating method |
| CN110687555A (en) * | 2019-09-23 | 2020-01-14 | 西安空间无线电技术研究所 | Navigation satellite atomic clock weak frequency hopping on-orbit autonomous rapid detection method |
| CN115015630A (en) * | 2022-05-31 | 2022-09-06 | 天津大学 | Ultra-weak frequency offset signal detection system and method based on photoelectric oscillator |
-
2007
- 2007-12-03 CN CNB2007101947530A patent/CN100567998C/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101458279B (en) * | 2008-12-09 | 2010-11-03 | 中国科学院国家授时中心 | Frequency measurement method by beat method capable of enhancing precision |
| CN106059575A (en) * | 2016-05-23 | 2016-10-26 | 中国舰船研究设计中心 | Boat-carrying information system frequency standard calibrating device and calibrating method |
| CN110687555A (en) * | 2019-09-23 | 2020-01-14 | 西安空间无线电技术研究所 | Navigation satellite atomic clock weak frequency hopping on-orbit autonomous rapid detection method |
| CN115015630A (en) * | 2022-05-31 | 2022-09-06 | 天津大学 | Ultra-weak frequency offset signal detection system and method based on photoelectric oscillator |
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| Publication number | Publication date |
|---|---|
| CN100567998C (en) | 2009-12-09 |
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