CN108872702A - The frequency measuring system and method in adaptive period - Google Patents
The frequency measuring system and method in adaptive period Download PDFInfo
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- CN108872702A CN108872702A CN201810521299.3A CN201810521299A CN108872702A CN 108872702 A CN108872702 A CN 108872702A CN 201810521299 A CN201810521299 A CN 201810521299A CN 108872702 A CN108872702 A CN 108872702A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
- G01R23/02—Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
- G01R23/10—Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage by converting frequency into a train of pulses, which are then counted, i.e. converting the signal into a square wave
Abstract
A kind of frequency measuring system and method in adaptive period, including frequency measurement interface, filtering and Shaping Module, signal measurement module, high steady temperature compensating crystal oscillator and communication module and interface.Wherein, frequency measurement interface is for inputting measured signal；Filtering is used to filter out the interference signal outside measurement range with Shaping Module, and converts square-wave signal for the signal after filtering out；Signal measurement module carries out step-by-step counting and frequency calculates, sampled signal periodicity carries out dynamically adapting adjusting according to measured signal frequency for capturing the signal edge of square-wave signal；And communication module and interface, it is used for transmission frequency data.The frequency measuring system in adaptive period of the invention carries out sampled measurements using multi-period Synchronous frequency measurement method to measured signal, sampled signal periodicity carries out dynamically adapting adjusting according to signal frequency, extension system frequency measurement range while guaranteeing measurement accuracy and response speed.
Description
Technical field
The invention belongs to sensor apparatus technologies and measurement and control area technical field, and in particular to a kind of frequency in adaptive period
Rate measuring system and method.
Background technique
The rate and required precision that aviation field acquires data are higher.Such as, aviation resonance type pressure sensor frequency
Rate acquisition rate requires 50 times/second, and sensor frequency measurement accuracy is better than ± 0.1Hz.Since resonance type pressure sensor works
The particularity of principle, output frequency directly characterizes pressure indicating value, thus has relatively wide frequency range, usually occupies
In 40~150kHz frequency range.Therefore it needs to realize high-precision in the case where wider frequency range and shorter sampling time require
The method of frequency measurement.
Traditional frequency measuring method includes cycle test method and two kinds of counting method.Cycle test method is suitable for low-band signal, and frequency is lower,
It is higher to measure relative accuracy, but response speed is slow；Counting method is suitable for high band, and frequency is higher, and measurement relative accuracy is higher.For
The problem of taking into account measurement accuracy and response speed, has developed multi-period synchronous measuring method.It is same within the specified signal period
When counted to measured signal with standard signal, according to the count value of measured signal and standard signal solve measured signal frequency
Method.Under normal conditions, multi-period synchronous measuring method is measured to measured signal using fixed periodic quantity, thus different
Frequency signal will occupy different sampling stages, cause its measurement error related to frequency signal itself.Furthermore at digital signal
A main source of error during reason is the counting error of digital signal.To reduce measurement error, it usually needs extension is adopted
The sample time realizes the average effect of counting error, and it is slack-off to measure response speed so as to cause it.Document shows in relative accuracy
It is 10-6Under the conditions of, the corresponding sampling time is 0.1s.Therefore, it is while to guarantee that response speed and frequency-measurement accuracy also need new
Test method and technology.
Summary of the invention
In view of the deficiencies of the prior art, the purpose of the present invention is to provide a kind of frequency measuring system in adaptive period with
Method, at least one of to solve the above problems.
The present invention is achieved through the following technical solutions：
As one aspect of the present invention, a kind of frequency measuring system in adaptive period is provided, including：Frequency measurement connects
Mouthful, for inputting measured signal, and it can be avoided when measured signal accesses and measured signal had an impact；Filtering and sizing die
Block, for filtering out from the interference signal outside the signal intermediate frequency rate measurement range that the frequency measurement interface inputs, and after filtering out
Signal be converted into square-wave signal；Signal measurement module, for capturing the square wave letter by the filtering with Shaping Module conversion
Number signal edge, carry out step-by-step counting and frequency and calculate, the signal measurement module has capture signal edge while latching
The function of counter register, sampled signal periodicity carry out dynamically adapting adjusting according to measured signal frequency；High steady temperature compensation is brilliant
Vibration carries out step-by-step counting for signal measurement module, the time source as frequency measurement for providing accurate pulse signal；And
Communication module and interface are used for transmission the frequency data that the signal measurement module is measured, realize the frequency measuring system
With the interaction of user.
Preferably, the frequency measurement interface is high-impedance state input interface.
Preferably, the signal measurement module is MCU module or FPGA module.
Preferably, the MCU module is to support the series of products of input capture timer configuration.
Preferably, the frequency values of the high steady temperature compensating crystal oscillator are no more than the maximum frequency that the MCU module is supported, with full
The supported maximum frequency of foot is advisable；Its temperature range is the range for covering the measuring system and using temperature；Its frequency stability
Answer the relative accuracy of at least 2 times frequency measuring systems；Its output signal is square-wave signal, and supported by MCU module
Logic level.
As another aspect of the present invention, a kind of frequency measurement method in adaptive period is provided, is included the following steps：
(1) measured signal accesses measuring system through frequency measurement interface；(2) measured signal is converted to square wave by filtering and Shaping Module
Signal；(3) initial samples periodicity n is given, signal measurement module completes n signal sampling, and calculates frequency input signal fc,
According to sampling time upper limit t, next sampling period number n is calculatednewFor nnew=[tfc], wherein [] is rounding operation；(4)
After the completion of frequency measurement, frequency measurement data is transferred to communication module.
Preferably, the operation program of the signal measurement module includes main program and interruption service function program, the master
Program carries out system configuration, configures signal period times of collection n, and timer is made to start counting device clock pulse count and edge
Capture, main program cycle inquire status indicator flag, wait frequency measurement completion status flag=1；The service function program
It carries out capture counting and counter overflow counts, and read timer latched value；When first time capture measured signal rising edge or
After failing edge, capture counts n=1, timer latching accumulator clock pulses numerical value ta；Whenever capture measured signal rising edge
Or failing edge, capture count n and add up to add 1；After capture, which counts, reaches setting value (N+1), when reading timer latching accumulator
Clock pulse count tb, and and timer is made to stop counter clock step-by-step counting and edge capture, and flag states completion
Flag=1；Main program detects that completion status identifies, then carries out frequency calculating, completes one-shot measurement.
Preferably, measured signal frequency fcCalculation method be：fc=N/ (tb-ta)·f0Wherein, f0For test macro
Clock frequency.
It can be seen from the above technical proposal that the frequency measuring system in adaptive period of the invention is with method with following
Beneficial effect：
(1) cycle parameter adjustment mode is simple, is not necessarily to complex calculation；
(2) mode for carrying out frequency measurement based on timer input capture reduces the instruction time, improves measurement accuracy；
(3) frequency measurement of quick high accuracy can be achieved, the response time is short, and measurement accuracy is still higher；
(4) frequency measurement range is expanded, the correlation of measurement error and frequency is obviously reduced.
Detailed description of the invention
Fig. 1 is the frequency measuring system block diagram in adaptive period in the embodiment of the present invention；
Fig. 2 is the frequency measurement method schematic diagram in adaptive period in the embodiment of the present invention；
Fig. 3 is software design process in the frequency measurement method in period adaptive in the embodiment of the present invention；
Fig. 4 is in the embodiment of the present invention using fixed cycle sampling and adaptive integral period sampling Comparative result.
Specific embodiment
To make the objectives, technical solutions, and advantages of the present invention clearer, below in conjunction with specific embodiment, and reference
Attached drawing, the present invention is described in further detail.
The present invention provides the frequency measuring systems and method in a kind of adaptive period, including frequency measurement interface, filtering
With Shaping Module, signal measurement module, high steady temperature compensating crystal oscillator and communication module and interface.Wherein, frequency measurement interface is used for
Input measured signal；Filtering with Shaping Module for the interference signal other than rejection frequency measurement range, and by the letter after filtering out
Number it is converted into square-wave signal；Signal measurement module carries out step-by-step counting and frequency meter for capturing the signal edge of square-wave signal
Calculate, signal measurement module have capture signal edge simultaneously latching accumulator register function, sampled signal periodicity according to
Measured signal frequency carries out dynamically adapting adjusting；High steady temperature compensating crystal oscillator, provides accurate pulse signal, carries out for signal measurement module
Step-by-step counting, the time source as frequency measurement；And communication module and interface, it is used for transmission frequency data.It is of the invention from
The frequency measuring system for adapting to the period carries out sampled measurements, sampling letter using multi-period Synchronous frequency measurement method to measured signal
Number periodicity carries out dynamically adapting adjusting according to signal frequency, and extension system is surveyed while guaranteeing measurement accuracy and response speed
Frequency range.
Specifically, as one aspect of the present invention, a kind of frequency measuring system in adaptive period is provided, including：Frequently
Rate measures interface, for inputting measured signal, and can be avoided when measured signal accesses and has an impact to measured signal；Filtering with
Shaping Module, for filtering out from the interference signal outside the signal intermediate frequency rate measurement range that the frequency measurement interface inputs, and will
Signal after filtering out is converted into square-wave signal；Signal measurement module, for capturing by the filtering and Shaping Module conversion
The signal edge of square-wave signal, carries out step-by-step counting and frequency calculates, and it is same that the signal measurement module has capture signal edge
When latching accumulator register function, sampled signal periodicity according to measured signal frequency carry out dynamically adapting adjusting；Gao Wen
Temperature compensating crystal oscillator carries out step-by-step counting for signal measurement module, the time as frequency measurement for providing accurate pulse signal
Source；And communication module and interface, the frequency data that the signal measurement module is measured are used for transmission, realize that the frequency is surveyed
The interaction of amount system and user.
The frequency measurement interface is high-impedance state input interface.
The signal measurement module is MCU module or FPGA module.
The MCU module is to support the series of products of input capture timer configuration.
To meet, MCU supports maximum frequency to be advisable to the frequency values of the high steady temperature compensating crystal oscillator；Its temperature range is to cover
The measuring system uses the range of temperature；Its frequency stability should at least 2 times frequency measuring systems relative accuracy；Its
Output signal is square-wave signal, and the logic level supported by MCU module.As another aspect of the present invention, one is provided
The frequency measurement method in kind adaptive period, includes the following steps：(1) measured signal is through frequency measurement interface, access measurement system
System；(2) measured signal is converted to square-wave signal by filtering and Shaping Module；(3) initial samples periodicity n, signal measurement are given
Module completes n signal sampling, and calculates frequency input signal fc, according to sampling time upper limit t, calculate next sampling period number
nnewFor nnew=[tfc], wherein [] is rounding operation；(4) after the completion of frequency measurement, frequency measurement data is transferred to communication
Module.
The operation program of the signal measurement module includes main program and interrupts service function program, and the main program carries out
System configuration configures signal period times of collection n, and timer is made to start counting device clock pulse count and edge capture, main
Program cyclic query status indicator flag waits frequency measurement completion status flag=1；The service function program is captured
It counts and counter overflow counts, and read timer latched value；After first time capture measured signal rising edge or failing edge,
Capture counts n=1, timer latching accumulator clock pulses numerical value ta；Whenever capture measured signal rising edge or failing edge,
Capture counts n and adds up to add 1；After capture, which counts, reaches setting value (N+1), timer latching accumulator clock pulse count is read
Value tb, and so that timer is stopped counter clock step-by-step counting and edge capture, and flag states complete flag=1；Main program
It detects that completion status identifies, then carries out frequency calculating, complete one-shot measurement.
Measured signal frequency fcCalculation method be：fc=N/ (tb-ta)·f0, wherein f0For the clock frequency of test macro
Rate.
Below in conjunction with specific embodiments and the drawings, frequency measuring system and method to the adaptive period of the invention make into
The detailed description of one step.
Embodiment
Fig. 1 is the frequency measuring system block diagram in adaptive period.As shown in Figure 1.The frequency measuring system in adaptive period
Block diagram system includes frequency measurement interface, filtering and Shaping Module, MCU module, high steady temperature compensating crystal oscillator and communication module and connects
Mouthful.Wherein, filtering is with Shaping Module for filtering the interference signal in addition to measurement range and being translated into square-wave signal；
MCU is the series of products for supporting input capture timer configuration, such as STM32.The Series MCU has capture signal edge simultaneously
Latching accumulator register functions can reduce MCU instruction operation, promote the net synchronization capability of timing.Surely temperature compensating crystal oscillator is height used
24MHz ± 0.5ppm, temperature range are -40 DEG C~+85 DEG C, export the square-wave signal of COMS level.
Fig. 2 is the frequency measurement method schematic diagram in adaptive period.As shown in Figure 2.MCU enables timer, and timer is opened
Begin to carry out clock signal counting.When MCU captures the rising edge of measured signal, then present counter value t is recordeda；When detecting
(N+1) a frequency signal rising edge, then recording counter value tb, hereafter control signal-off clock counter.It is assumed that standard
Clock frequency f0, then it is assumed that time T shared by N number of signal periodcFor：
Tc=(tb-ta)/f0 (1)
In fact, error present in above-mentioned measurement process is when first rising edge and the last one rising edge timer
The counting deviation of latch is 1 standard clock signal, therefore the frequency of standard time clock used is higher, and time measurement error is got over
Small, measurement result is more accurate.With this condition, measured signal measurement frequency fcFor：
fc=N/ (tb-ta)·f0 (2)
Frequency measurement relative error ζ is：
ζ=1/ (tb-ta) (3)
Therefore, to improve measurement accuracy, it should guarantee enough time of measuring as far as possible.But work as frequency measurement wider range
When, the time of measuring that fixed cycle numbers catching method will lead to measurement upper limiting frequency shortens, and then introduces biggish measurement error.
To compensate its defect, the present invention uses a kind of measurement method of adaptive periodicity.As, in given initial samples periodicity n
Afterwards, MCU completes n signal sampling, and calculates measured signal frequency fc.According to sampling time upper limit t, then next sampling can be calculated
Periodicity nnewFor,
nnew=[tfc] (4)
Wherein, [] indicates round numbers operation.This method can adapt to automatically according to the variation of frequency, be no more than the sampling time limit
Under the premise of, realize that periodicity maximumlly measures.
Fig. 3 is software design process in the frequency measurement method in adaptive period.As shown in figure 3, programming includes master
Program and interruption service function program, main program carry out system configuration, configure signal period times of collection, and enabled timer.
Hereafter, main program cycle inquires status indicator, waits frequency measurement completion status.Service function carries out capture counting and counter
It overflows and counts, and read timer latched value.After capture, which counts, reaches (N+1), then disable timer, and flag states are complete
At.Main program detects that completion status identifies, then carries out frequency calculating, and send frequency, completes one-shot measurement.Measurement next time will
Next times of collection is automatically updated according to current frequency value, realizes maximum time sampling.
Fig. 4 is fixed cycle sampling and adaptive integral period sampling Comparative result.As shown in figure 4, sampling time limit t=20ms,
Sampling test is carried out using the fixed cycle 1000, for 50kHz frequency from signal, the measurement error of two methods is identical；For
200kHz frequency signal, fixed cycle sampled measurements deviation reaches 0.25Hz or more, and uses adaptive frequency sampling measured deviation
Less than 0.1Hz.Therefore, the present invention can be obviously improved measurement accuracy and expand measurement range.
In conclusion the frequency measuring system in adaptive period of the invention uses multi-period Synchronous frequency measurement method pair
Measured signal carries out sampled measurements, and sampled signal periodicity carries out dynamically adapting adjusting according to signal frequency, is guaranteeing measurement essence
Degree and extension system frequency measurement range while response speed.
Particular embodiments described above has carried out further in detail the purpose of the present invention, technical scheme and beneficial effects
Describe in detail bright, it should be understood that the above is only a specific embodiment of the present invention, is not intended to restrict the invention, it is all
Within the spirit and principles in the present invention, any modification, equivalent substitution, improvement and etc. done should be included in protection of the invention
Within the scope of.
Claims (8)
1. a kind of frequency measuring system in adaptive period, which is characterized in that including：
Frequency measurement interface for inputting measured signal, and can be avoided when measured signal accesses and have an impact to measured signal；
Filtering and Shaping Module, for filtering out from the interference outside the signal intermediate frequency rate measurement range that the frequency measurement interface inputs
Signal, and square-wave signal is converted by the signal after filtering out；
Signal measurement module is carried out for capturing the signal edge by the filtering and the square-wave signal of Shaping Module conversion
Step-by-step counting and frequency calculate, the function of latching accumulator register while the signal measurement module has capture signal edge
Can, sampled signal periodicity carries out dynamically adapting adjusting according to measured signal frequency；
High steady temperature compensating crystal oscillator carries out step-by-step counting for signal measurement module, as frequency measurement for providing accurate pulse signal
Time source；And
Communication module and interface are used for transmission the frequency data that the signal measurement module is measured, realize the frequency measurement
The interaction of system and user.
2. the frequency measuring system in adaptive period according to claim 1, which is characterized in that
The frequency measurement interface is high-impedance state input interface.
3. the frequency measuring system in adaptive period according to claim 1, which is characterized in that
The signal measurement module is MCU module or FPGA module.
4. the frequency measuring system in adaptive period according to claim 1, which is characterized in that
The MCU module is to support the series of products of input capture timer configuration.
5. the frequency measuring system in adaptive period according to claim 1, which is characterized in that
The frequency values of the high steady temperature compensating crystal oscillator are the maximum frequency values supported no more than the MCU module, and with MCU module branch
Holding maximum frequency is advisable；Its temperature range is the range for covering the measuring system and using temperature；Its frequency stability should at least 2
The relative accuracy of times frequency measuring system；Its output signal is square-wave signal, and the logic electricity supported by MCU module
It is flat.
6. a kind of frequency measurement method in adaptive period, using the adaptive period according to any one of claims 1 to 4
Frequency measuring system, which is characterized in that include the following steps：
(1) measured signal accesses measuring system through frequency measurement interface；
(2) measured signal is converted to square-wave signal by filtering and Shaping Module；
(3) initial samples periodicity n is given, signal measurement module completes n signal sampling, and calculates measured signal frequency fc, root
According to sampling time upper limit t, next sampling period number n is calculatednewFor,
nnew=[tfc], wherein [] is rounding operation；
(4) after the completion of frequency measurement, frequency measurement data is transferred to communication module.
7. the frequency measurement method in adaptive period according to claim 6, which is characterized in that
The operation program of the signal measurement module include main program and interrupt service function program,
The main program carries out system configuration, configures signal period times of collection n, and timer is made to start counting device clock pulses
It counts and is captured with edge, main program cycle inquires status indicator flag, waits frequency measurement completion status flag=1；
The service function program carries out capture counting and counter overflow counts, and reads timer latched value；When for the first time
After capturing measured signal rising edge or failing edge, capture counts n=1, timer latching accumulator clock pulses numerical value ta；Often
When capture measured signal rising edge or failing edge, capture counts n and adds up to add 1；After capture, which counts, reaches setting value (N+1), read
Take timer latching accumulator clock pulses numerical value tb, and so that timer is stopped counter clock step-by-step counting and caught with edge
It obtains, and flag states complete flag=1；
Main program detects that completion status identifies, then carries out frequency calculating, completes one-shot measurement.
8. the frequency measurement method in adaptive period according to claim 6, which is characterized in that measured signal frequency fc's
Calculation method is：
fc=N/ (tb-ta)·f0；
Wherein, f0For the clock frequency of test macro.
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| CN110007144A (en) * | 2019-04-30 | 2019-07-12 | 杭州万高科技股份有限公司 | A kind of frequency measurement method and associated component of input signal |
| CN110361595A (en) * | 2019-07-22 | 2019-10-22 | 西安电子科技大学 | A kind of frequency measuring system in adaptive period |
| CN110988467A (en) * | 2019-12-18 | 2020-04-10 | 北京自动化控制设备研究所 | Frequency measurement system and frequency measurement method thereof |
| CN111103456A (en) * | 2019-12-30 | 2020-05-05 | 四川锐智电气科技有限公司 | Frequency measurement method and device for locomotive control system |
| CN111679091A (en) * | 2020-04-30 | 2020-09-18 | 中国航发南方工业有限公司 | High-real-time segmented self-adaptive rotating speed measuring method, device, medium and equipment |
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| CN112858780A (en) * | 2020-12-31 | 2021-05-28 | 广东大普通信技术有限公司 | Method, device and system for measuring crystal oscillation frequency |
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| CN112858780A (en) * | 2020-12-31 | 2021-05-28 | 广东大普通信技术有限公司 | Method, device and system for measuring crystal oscillation frequency |
| CN113049878A (en) * | 2021-03-04 | 2021-06-29 | 中国科学院微小卫星创新研究院 | Satellite frequency measurement system and method |
| CN113341221A (en) * | 2021-04-29 | 2021-09-03 | 浙江万里学院 | Whole-period sampling circuit and whole-period sampling method in harmonic analysis |
| CN113419110A (en) * | 2021-06-21 | 2021-09-21 | 四川都睿感控科技有限公司 | Frequency shift signal frequency detection system and method based on ZPW2000 track circuit |
| CN114221659A (en) * | 2022-02-22 | 2022-03-22 | 成都凯天电子股份有限公司 | Method and system for improving conversion precision of low-frequency signal and electronic equipment |
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Application publication date: 20181123 |