CN116147754A - Ultrahigh frequency target vibration characteristic extraction method - Google Patents
Ultrahigh frequency target vibration characteristic extraction method Download PDFInfo
- Publication number
- CN116147754A CN116147754A CN202310296072.4A CN202310296072A CN116147754A CN 116147754 A CN116147754 A CN 116147754A CN 202310296072 A CN202310296072 A CN 202310296072A CN 116147754 A CN116147754 A CN 116147754A
- Authority
- CN
- China
- Prior art keywords
- carrier signal
- information
- phase
- target
- frequency
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000605 extraction Methods 0.000 title claims abstract description 12
- 238000000034 method Methods 0.000 claims abstract description 12
- 238000005259 measurement Methods 0.000 claims abstract description 9
- 238000006073 displacement reaction Methods 0.000 claims description 9
- 230000001133 acceleration Effects 0.000 claims description 4
- 238000001914 filtration Methods 0.000 claims description 3
- 230000010355 oscillation Effects 0.000 claims description 3
- 238000006243 chemical reaction Methods 0.000 claims description 2
- 238000012546 transfer Methods 0.000 claims description 2
- 230000001427 coherent effect Effects 0.000 abstract description 5
- 239000000969 carrier Substances 0.000 abstract description 2
- 238000013139 quantization Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Abstract
An ultrahigh frequency target vibration characteristic extraction method relates to the technical field of laser coherent vibration measurement and solves the problem that the accuracy of extracting target vibration information of a laser ultrahigh frequency vibration measurement system still needs to be improved, and the method comprises the following steps: calculating to obtain a phase error gain factor according to the amplitude deviation between an in-phase carrier signal I of a baseband signal and a quadrature carrier signal Q of the baseband signal, the deviation between I and the ideal carrier signal frequency and the deviation between Q and the ideal carrier signal frequency; and obtaining the target vibration information by using a target vibration information compensation algorithm model containing the phase error gain factors. The invention carries out quantization compensation on the phase error caused by amplitude and frequency deviation, reduces the influence of uneven modulation of two paths of carriers on demodulation precision, and realizes high-precision demodulation of the ultrahigh frequency micro-vibration signal.
Description
Technical Field
The invention relates to the technical field of laser coherent vibration measurement, in particular to an ultrahigh frequency target vibration characteristic extraction method.
Background
In the field of laser Doppler ultrahigh frequency micro-vibration measurement, a target vibration demodulation algorithm mainly comprises a differential cross multiplication algorithm and an arctangent phase discrimination algorithm, wherein arctangent becomes a main demodulation mode due to simple implementation mode and amplitude noise suppression. The traditional arctangent demodulation mode can recover the phase generated by target modulation only according to a simple trigonometric function relation, and further extracts the target vibration information.
The traditional arctangent micro-vibration signal demodulation algorithm relies on orthogonality of photocurrent signals output by a detector, and the micro-vibration signals are demodulated with high precision by using orthogonal baseband signals. Because the amplitude and the phase actual measurement value of the baseband signal deviate from the theoretical value, if the micro-vibration signal is demodulated in an ideal orthogonal mode by the traditional arctangent algorithm, the demodulation precision is reduced, and the characteristics of the micro-vibration signal cannot be accurately extracted.
Therefore, a new demodulation algorithm research is required to be designed to realize high-precision demodulation of the ultra-high frequency micro-vibration signal.
Disclosure of Invention
The invention provides a method for extracting ultrahigh frequency target vibration characteristics, which aims to solve the problem that the accuracy of extracting target vibration information of a laser ultrahigh frequency vibration measuring system still needs to be improved.
The technical scheme adopted by the invention for solving the technical problems is as follows:
the ultrahigh frequency target vibration characteristic extraction method comprises the following steps:
step one, according to the amplitude deviation Delta U, I between the in-phase carrier signal I of the baseband signal and the quadrature carrier signal Q of the baseband signal and the deviation f between the ideal carrier signal frequencies ei And the deviation f between Q and the ideal carrier signal frequency eq Calculating to obtain a phase error gain factor delta;
and secondly, obtaining target vibration information by using a target vibration information compensation algorithm model containing delta.
The beneficial effects of the invention are as follows:
the ultrahigh frequency target vibration characteristic extraction method disclosed by the invention carries out quantization compensation on the phase error caused by amplitude and frequency deviation, and reduces the influence of uneven modulation of two paths of carriers on demodulation precision. The phase caused by the target vibration is accurately compensated by using the target vibration information compensation algorithm model, so that the target vibration information can be accurately extracted, and the high-precision demodulation of the ultrahigh frequency micro-vibration signal is realized.
Drawings
Fig. 1 is a flowchart of a method for extracting ultrahigh frequency target vibration characteristics according to the present invention.
Fig. 2 is a diagram of a quadrature demodulation process of an ultrahigh frequency target vibration feature extraction method according to the present invention.
Fig. 3 is a diagram showing an arctangent demodulation process of an ultra-high frequency target vibration feature extraction method according to the present invention.
Detailed Description
The invention will be described in further detail with reference to the drawings and examples.
An ultrahigh frequency target vibration characteristic extraction method, as shown in figure 1, specifically comprises the following steps:
the photocurrent signals are mixed with two paths of carrier signals respectively and pass through a low-pass filter, a difference frequency component containing target vibration information is reserved, a sum frequency component containing high-frequency noise is removed, and two paths of quadrature I & Q baseband signals are obtained.
Two-way I&The amplitude and frequency of the Q baseband signal (I means the in-phase carrier signal of the baseband signal and Q means the quadrature carrier signal of the baseband signal) always deviate due to noise, and thus the target vibration information demodulated by arctangent also deviates, so that accurate demodulation of the target vibration information using phase compensation is required. Assuming that the amplitude deviation of the two carrier signals is DeltaU, the deviation between the two carrier signals and the ideal carrier signal frequency is f ei and feq . Thus, the two baseband signals may be represented as
wherein ,ui (t) represents the amplitude of the in-phase carrier signal of the baseband signal,u q (t) the amplitude of the quadrature carrier signal of the baseband signal, U the amplitude of the ideal carrier signal, deltaU the amplitude deviation of the in-phase carrier signal and the quadrature carrier signal, f ei Representing the deviation between the in-phase carrier signal and the ideal carrier signal frequency, f eq Representing the deviation between the orthogonal carrier signal and the ideal carrier signal frequency, t representing time, f c Representing the ideal carrier signal frequency.
In order to obtain target vibration information, the photocurrent signals are mixed with two paths of carrier signals respectively and then pass through a low-pass filter, a difference frequency component containing the target vibration information is reserved, a sum frequency component containing high-frequency noise is removed, and two paths of quadrature I are obtained&Q baseband signal. The quadrature demodulation process is shown in fig. 2: photocurrent signal and sine carrier signal sin (2pi.f AOM t) performing coherent mixing in the first mixer 1, filtering the difference frequency component generated after mixing by the first low-pass filter 2, and mixing the photocurrent signal with the cosine carrier signal cos (2pi f) AOM t) respectively performing coherent mixing in the second mixer 3, filtering the difference frequency component generated after mixing by the second low-pass filter 4, and reserving the difference frequency component containing target vibration information to obtain mutually orthogonal baseband signals, wherein the orthogonal baseband signals are important preconditions for subsequent signal processing. Sin (2pi.f) in FIG. 2 AOM t) represents an in-phase carrier signal, cos (2pi.f) AOM t) represents the quadrature carrier signal, f AOM Representing the carrier frequency of the acousto-optic modulator.
Wherein I (t) represents an in-phase carrier signal of the baseband signal, Q (t) represents a quadrature carrier signal of the baseband signal, Δi (t) represents a photocurrent signal, h LPF Representing the transfer function of the low-pass filter, K representing the photoelectric conversion parameter, P m and Pr Respectively representing the power of the measuring light and the local oscillation light,
representation of inclusion orderPhase information of the target shift information s (t),/for the target shift information s (t)>
To delay the phase, λ represents the wavelength of the measurement light.
From the expression formula (2) of the two baseband signals, it is possible to derive a signal containing the target displacement information s (t), the amplitude deviation DeltaU and the frequency deviation f ei and feq Is a calculated phase value of (a)
On this basis, we define a phase error gain factor comprising phase information and offset information,
the phase deviation caused by instability of the carrier signal can be expressed as an expression of a phase error gain factor,
wherein ,
representing phase deviations due to instability of the in-phase carrier signal and the quadrature carrier signal, +.>
Namely->
The amplitude deviation DeltaU is a very small quantity, the frequency deviation f ei and feq The two are approximately equal, so the phase error gain factor delta is a very small quantity, and the invention can utilize the Taylor series expansion to perform Taylor expansion on f (delta) so as to obtain
Wherein o (·) represents a higher order infinitely small.
Thus, a target vibration information compensation algorithm model containing the phase error gain factor delta is obtained. Firstly, a phase error gain factor is obtained according to amplitude deviation delta U and frequency deviation of two paths of carrier signals, and then a target vibration information compensation algorithm model is utilized to obtain a true value of target vibration information.
The target vibration information includes target displacement information, target velocity information, and target acceleration information. As in fig. 3, the arctangent demodulation process is shown: i (t) and Q (t) of the formula (2) are obtained after the I & Q two roadbed signals pass through the corresponding low-pass filter, division operation (formula (3)) is carried out on the I (t) and the Q (t) in the divider (5), then demodulation (corresponding f (delta)) is carried out on a tangent function containing target vibration information in the arc tangent arithmetic unit (6), phase information containing target vibration characteristics is obtained, the phase information is continuous by the phase unwrapping module (7) (namely, a phase unwrapping algorithm is utilized), target displacement information can be obtained after continuous phase information enters the band-pass filter (8), target velocity information can be obtained through primary differential operation on the target displacement information in the differentiator (9), and target acceleration information can be obtained through secondary differential operation.
The laser Doppler ultrahigh frequency micro-vibration measurement technology utilizes the coherent superposition of local oscillation light and signal light to convert a high frequency light wave signal into an intermediate frequency signal, and then converts the intermediate frequency signal into a baseband signal through the modulation-demodulation technology of a carrier signal, thereby realizing the measurement of Doppler frequency shift caused by a micro-vibration target and recovering the vibration characteristic of the detection target. Wherein the stability of the carrier signal is an important factor in determining the characteristics of the micro-vibration target, and the stability of the carrier signal includes amplitude stability and frequency stability. According to the technical scheme, the amplitude and frequency deviation caused by carrier instability are quantized, the phase error caused by the amplitude and frequency deviation is quantized and compensated, and the influence of two paths of carrier modulation unevenness on demodulation precision is reduced.
Due to the instability of carrier frequency in a laser ultrahigh frequency vibration measuring system, demodulation accuracy of vibration information is often required to be improved through phase compensation. According to the invention, an arctangent phase compensation algorithm is established, a phase error compensation factor is introduced, quantitative compensation is carried out on the demodulation output phase containing the target vibration information, and accurate compensation is carried out on demodulation precision reduction caused by the amplitude and phase deviation of the baseband signal. The invention directly calculates the numerical value of the phase error compensation factor through the amplitude and frequency deviation of the carrier signal, and accurately compensates the phase caused by the target vibration, wherein the phase is obtained through Doppler frequency shift demodulation caused by the target vibration, so that the target vibration information can be accurately extracted.
Furthermore, descriptions such as those referred to as "first," "second," and the like, are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying an order of magnitude of the indicated technical features in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.
Claims (6)
1. The ultrahigh frequency target vibration characteristic extraction method is characterized by comprising the following steps of:
step one, according to the amplitude deviation Delta U, I between the in-phase carrier signal I of the baseband signal and the quadrature carrier signal Q of the baseband signal and the deviation f between the ideal carrier signal frequencies ei And the deviation f between Q and the ideal carrier signal frequency eq Calculating to obtain a phase error gain factor delta;
and secondly, obtaining target vibration information by using a target vibration information compensation algorithm model containing delta.
2. The method for extracting ultrahigh frequency target vibration characteristics according to claim 1, wherein the target vibration information compensation algorithm model is as follows:
wherein ,
representing the phase value +.>
Representing phase information comprising target displacement information s (t), for example>
To delay the phase, λ represents the wavelength of the measurement light, and o (·) represents a higher order infinitely small.
3. The ultrahigh frequency target vibration feature extraction method of claim 2, wherein I and Q are expressed as:
wherein ,ui (t) represents the amplitude of the in-phase carrier signal of the baseband signal, u q (t) the amplitude of the quadrature carrier signal of the baseband signal, U the amplitude of the ideal carrier signal, deltaU the amplitude deviation of the in-phase carrier signal and the quadrature carrier signal, f ei Representing the deviation between the in-phase carrier signal and the ideal carrier signal frequency, f eq Representing the deviation between the orthogonal carrier signal and the ideal carrier signal frequency, t representing time, f c Representing the ideal carrier signal frequency.
4. The method for extracting ultrahigh frequency target vibration characteristics as defined in claim 3, wherein the method for obtaining the target vibration information compensation algorithm model comprises the following steps:
mixing the photocurrent signal with I and Q respectively, and passing through a low-pass filter after mixing to retain the difference frequency component containing the target vibration information, and removing the sum frequency component containing high-frequency noise to obtain
Wherein I (t) represents an in-phase carrier signal of the baseband signal, Q (t) represents a quadrature carrier signal of the baseband signal, Δi (t) represents a photocurrent signal, h LPF Representing the transfer function of the low-pass filter, K representing the photoelectric conversion parameter, P m and Pr Respectively representing the power of the measuring light and the local oscillation light;
derived according to formula (2)
Defining a phase error gain factor delta comprising phase information and offset information as
Phase deviation caused by instability of in-phase carrier signal and quadrature carrier signal
An expression denoted as delta,
and (3) carrying out Taylor expansion on f (delta) by using a Taylor series expansion method, so as to obtain the target vibration information compensation algorithm model.
5. The ultrahigh frequency target vibration feature extraction method of claim 1, wherein the target vibration information comprises target displacement information, target velocity information, and target acceleration information.
6. The method according to claim 1, wherein the target displacement information is obtained by filtering continuous phase information with a band-pass filter, the target velocity information is obtained by differentiating the target displacement information once in a differentiator, and the target acceleration information is obtained by differentiating the target displacement information twice in the differentiator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310296072.4A CN116147754A (en) | 2023-03-24 | 2023-03-24 | Ultrahigh frequency target vibration characteristic extraction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310296072.4A CN116147754A (en) | 2023-03-24 | 2023-03-24 | Ultrahigh frequency target vibration characteristic extraction method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116147754A true CN116147754A (en) | 2023-05-23 |
Family
ID=86352640
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310296072.4A Pending CN116147754A (en) | 2023-03-24 | 2023-03-24 | Ultrahigh frequency target vibration characteristic extraction method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116147754A (en) |
-
2023
- 2023-03-24 CN CN202310296072.4A patent/CN116147754A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11168975B2 (en) | Phase delay extraction and compensation method in PGC phase demodulation technology | |
| US4143322A (en) | Carrier wave recovery system apparatus using synchronous detection | |
| CN104964735B (en) | A kind of detecting system and demodulation method of laser phase carrier doppler vibration signal | |
| EP0478265A1 (en) | Phase based vector modulator | |
| CN111609792B (en) | Phase delay compensation method in PGC phase demodulation method | |
| CN112134136B (en) | Fiber laser frequency stabilization system using fast and slow locking | |
| US6442383B1 (en) | Demodulator and digital wireless communication receiver | |
| US5212825A (en) | Synthetic heterodyne demodulator circuit | |
| CN111609791B (en) | Method for extracting and compensating modulation depth in PGC phase demodulation method | |
| CN104601506A (en) | Non-data aided OQPSK (Offset Quadra Phase Shift Keying) signal closed loop carrier synchronization method | |
| US6618404B2 (en) | Method for producing highly accurate frequency and FM of a laser | |
| CN116147754A (en) | Ultrahigh frequency target vibration characteristic extraction method | |
| KR0142943B1 (en) | Cdma | |
| CN117740047A (en) | Method and system for extracting and correcting phase modulation depth and eliminating nonlinear influence factors in PGC-Atan demodulation method | |
| CN114964001A (en) | Linear PGC demodulation signal processing method based on hybrid phase modulation | |
| CN204758116U (en) | Detecting system of laser phase carrier doppler vibration signal | |
| CN112923863B (en) | Secondary frequency conversion fiber grating resonance peak tracking detection system | |
| CN115022140A (en) | Method and apparatus for eliminating phase delay of phase demodulation carrier and compensating modulation depth | |
| CN1193504C (en) | Method and apparatus for improving capture and lock characteristics of phase lock loops | |
| Oka et al. | Real-time phase demodulator for optical heterodyne detection processes | |
| US4567486A (en) | Phase difference measurement technique for VOR | |
| RU2595638C1 (en) | Method for frequency modulation of oscillations and device therefor | |
| CN113834561B (en) | System and method for extracting and compensating phase modulation depth in PGC phase demodulation | |
| RU2510145C1 (en) | Method for restoring carrier frequency of phase-shift keyed signal and monitoring thereof | |
| EP0154963B1 (en) | Quarternary differential psk demodulator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |