250 results about "Lock-in amplifier" patented technology

The invention relates to a digital lock-in amplifier based on a frequency adaptive technology and a weak signal acquisition system and method, and the system comprises a front-end signal processing module which is used for obtaining a weak signal to be detected; the frequency self-adaptive tracking module is used for performing fast Fourier transform on the frequency of the weak signal to be measured to obtain the position of the maximum spectral line so as to synthesize a frequency control word, further generate a local reference signal and simultaneously adjust the coefficients of a low-pass filter and a loop filter and the series adjustment mode of a carrier synchronization ring; the multi-rate narrow-band low-pass filter module is used for multiplying the digital signal by a local reference signal and then carrying out filtering and down-sampling on a high-frequency signal to obtain a plurality of mutually orthogonal difference frequency components; the vector operation module is used for carrying out vector operation on the plurality of mutually orthogonal difference frequency components to obtain the phase and the amplitude in the weak signal to be measured; and the man-machine interaction module is used for displaying and storing the phase and the amplitude in the weak signal to be detected.

The invention relates to the technical field of quantum sensing and ocean detection, and discloses an ocean magnetic field sensor based on an NV color center and an ocean magnetic field measuring method.The sensor comprises a cylindrical pressure-resistant cabin, an optical platform arranged in the pressure-resistant cabin and a main control panel; a laser, a beam shaping unit, a dichroscope, a beam shaping lens group, an objective lens, a diamond NV color center chip, a plano-convex lens I, a band-pass filter and a photoelectric detector are mounted on the optical platform; two microstrip loop antennas are mounted on the outer side of the diamond NV color center chip; an FPGA + ARM dual-core processor, a digital lock-in amplifier and two microwave signal generators are installed on the main control board, and the microwave signal generators are connected with the microstrip loop antenna and achieve electromagnetic coupling with the diamond NV color center chip. The invention has the advantages of high sensitivity, good long-term stability and strong anti-interference capability, and provides a new generation of quantum sensing solution for applications such as ocean geomagnetic monitoring and underwater target identification.

The invention discloses a nonlinear dielectric constant measuring system based on a scanning nonlinear dielectric microscope, comprising: a probe, one end of which forms a micro capacitance Cs with the upper surface of a sample to be tested; the low-frequency signal module applies a low-frequency signal to the lower surface of the to-be-tested sample; the other end of the probe is connected with an LC resonance circuit in the probe module; the output end of a signal amplifier in the probe module is connected with a frequency modulation demodulator; the frequency modulation demodulator demodulates the frequency signal modulated by the probe module, removes a high-frequency carrier signal, inputs the demodulated signal into the lock-in amplifier, and detects, separates and amplifies a high-signal-to-noise-ratio signal by taking the frequency of a low-frequency signal applied to the sample to be tested as a reference frequency; according to the measurement system, the detection speed, the service life of the probe and the multi-material applicability can be remarkably improved, meanwhile, the thermal disturbance effect is inhibited, and a reliable solution is provided for accurate characterization of nano electronic devices.

The invention relates to the technical field of quantum sensing, and discloses a quantum magnetometer device based on diamond NV color center photoelectric detection magnetic resonance. Wherein the optical path module performs optical excitation and imaging positioning on a diamond sample through a laser and an objective lens. The circuit module integrates a microwave source, a lock-in amplifier, a low-noise current amplifier and a programmable power supply, applies a microwave field and bias voltage to a microwave antenna and an interdigital electrode on the surface of a sample respectively, and collects sample dependency photocurrent signals. And the operation module realizes automatic control and data processing of the system. According to the device, NV color center spin state information is converted into a photocurrent signal through a photoelectric detection magnetic resonance mechanism, an amplitude or frequency modulated signal is demodulated by using a lock-in amplification technology, information of a detection magnetic field is obtained through a high signal-to-noise ratio photoelectric detection magnetic resonance spectrum, and the sensitivity of the magnetic field is evaluated. Magnetic resonance signals are detected in an all-electricity mode, a complex optical system of traditional fluorescence detection is simplified, and the device has the advantages of being compact in structure, easy to integrate, high in measurement sensitivity and the like.

The invention discloses a multi-frequency digital phase-locked amplification method and device based on coherent sampling, and the method comprises the steps: applying multi-frequency sine reference signal excitation containing K reference frequencies to a measured object, and obtaining an impedance response signal of the measured object; performing coherent sampling on the impedance response signal; performing synchronous digital phase locking of K reference frequencies on the discrete impedance response signal sequence to obtain amplitudes and phases under the K reference frequencies; the device comprises a front-end unit and a rear-end unit, the front-end unit comprises a positive and negative current source and a current amplifier, and the rear-end unit comprises a control processing module, a DA conversion and low-pass filtering module and a low-pass filtering and AD conversion module. The invention aims to improve the digital lock-in amplifier so that the digital lock-in amplifier can synchronously process multi-frequency signals, reduce the design difficulty and resource consumption of a pass filter and improve the precision and speed of the lock-in amplifier, so that the digital lock-in amplifier is stable and reliable and has wide adaptability.

The invention relates to the field of mining laser gas detection, in particular to a modulation and demodulation method and system for carrier noise suppression, and the modulation and demodulation method comprises the following steps: S1, generating a driving current sequence through a laser gas sensor; s2, collecting a light intensity sequence to carry out data reconstruction; s3, extracting a harmonic signal, sending the reconstructed sequence into a lock-in amplifier, and respectively extracting a second harmonic signal and a first harmonic signal; and S4, detecting the gas concentration through the ratio by using the mapping relation between the gas concentration and the ratio of the second harmonic signal to the first harmonic signal. According to the method, a continuous data discrete reconstruction technology is introduced into a modulation and demodulation process, and a reference time sequence is generated by utilizing the characteristics of a laser output signal, so that self-matching and dynamic adjustment of modulation frequency are realized, external signal interference is effectively avoided, and the harmonic extraction stability is improved; meanwhile, the hardware structure is simplified, and the adaptability of the system to different gas absorption spectral lines is enhanced.

A quantum sensing module, a quantum current transformer, and a current measurement method, the quantum sensing module comprising a quantum probe (1), a laser module (2), a microwave module (3), a photoelectric detection module (4), a lock-in amplifier (5), a frequency locking module (6), and a data processing module (7); the quantum probe (1) comprises a diamond sensing unit (11) and a microwave radiator (12); the laser module (2) is configured to output an excitation laser; the microwave module (3) is configured to output a microwave signal; the photoelectric detection module (4) is configured to receive photoluminescence generated by the diamond sensing unit (11) and convert same into an output voltage signal; the lock-in amplifier (5) comprises a modulating unit and a demodulating unit; the frequency locking module (6) comprises a PID control unit and a frequency acquiring unit. The quantum current transformer comprises a quantum sensing module, which is configured to measure a current in a conductor. The current measurement method is applied to the quantum current transformer to obtain current information within the conductor. This improves magnetic detection efficiency and increases current measurement precision.

The embodiment of the invention provides a rubidium atomic clock based on a velocity grating spectrum and an implementation method, and the method comprises the steps: enabling a multi-frequency coherent laser source to emit a laser signal containing the velocity grating spectrum, and dividing the laser signal into two paths through a polarization splitting prism; the reflected light beam enters the laser frequency stabilization module to realize laser frequency stabilization; a transmission light beam enters the rubidium bubble through the lens group to interact with rubidium atoms; the photoelectric tube detects a transition spectral line, converts the transition spectral line from an optical signal into an electric signal and transmits the electric signal to the lock-in amplifier for demodulation; the integral amplification module converts the demodulated direct-current voltage into linear increasing voltage and transmits the linear increasing voltage to the crystal oscillator; the crystal oscillator generates an initial microwave signal and generates a microwave signal corresponding to the 87Rb atom through the frequency synthesizer; and the phase frequency modulation module modulates the microwave signal to obtain an error signal and transmits the error signal to the microwave resonant cavity so as to adjust the electromagnetic field according to the error signal to stably lock the rubidium atomic clock. The method is used for achieving the effect of improving the stability of the rubidium atomic clock system.

The invention discloses a terahertz gas insulated switch measuring device and method based on artificial intelligence, the terahertz gas insulated switch measuring device comprises a data imaging module and a data processing module, the data imaging module comprises a terahertz wave emission source, a lock-in amplifier module, a quasi-optical system and a high-sensitivity detector, and the data processing module comprises an upper computer; when the insulation degree of the gas insulated switch is measured, the data imaging module terahertz wave emission source generates terahertz waves, the terahertz waves are focused through the quasi-optical system and transmitted to the gas insulated switch equipment, the high-sensitivity detector receives the terahertz waves passing through the gas insulated switch equipment and converts the terahertz waves into electric signals, and the electric signals are transmitted to the gas insulated switch equipment. Further, the lock-in amplifier module amplifies and filters the electric signals output by the high-sensitivity detector, the data processing module receives the electric signals output by the lock-in amplifier module, defects are recognized through a noise reduction algorithm and a deep learning model, and a data processing result is displayed; the problems that traditional detection is low in precision, small in range, low in efficiency and the like are solved.

The invention discloses a device and a method for measuring the velocity field of an autoclave through hot-pressing wind speed. The device comprises a thermosensitive probe, a Wheatstone bridge, a lock-in amplifier, an NI multi-channel data acquisition card and a computer, the thermosensitive probe is used for instantaneously detecting the temperature of a placement point position and generating resistance fluctuation based on sensing temperature change; the Wheatstone bridge is formed by connecting a fixed resistor, a variable resistor and a thermosensitive probe, and is used for forming a series circuit with the lock-in amplifier; the lock-in amplifier is used for supplying power to the Wheatstone bridge and providing co-frequency voltage at the same time, so that resistance data of a thermosensitive probe in the Wheatstone bridge is converted into voltage data to be output; the NI multi-channel data acquisition card is used for acquiring in-phase component voltage signals output by the lock-in amplifier; the computer is used for processing the voltage data to obtain the average speed and the pulsation speed of the measurement point. According to the invention, the problems of limited precision, insufficient sensitivity and poor adaptability to the internal environment of the autoclave in the conventional gas speed measurement method are solved.

The invention relates to a high-precision temperature detection system based on an alternating-current impedance bridge. The high-precision temperature detection system comprises a double-resistance bridge circuit, a lock-in amplifier and a differential circuit, the double-resistor bridge circuit comprises a resistive temperature sensor and a standard resistor which are connected in series, and the phase-locked amplifier is a digital phase-locked amplifier realized based on an FPGA (Field Programmable Gate Array). Wherein the initial potential of a first voltage measurement end arranged at the midpoint of the double-resistor bridge circuit is zero by adjusting the two excitation signals which are loaded to the double-resistor bridge circuit and have the same frequency and opposite phases before temperature measurement; in the temperature measuring process, the lock-in amplifier detects the potential of the first voltage measuring end and the voltage at the two ends of the standard resistor through the differential circuit, then the resistance value of the resistance-type temperature sensor is calculated by combining the resistance value of the standard resistor, and then the temperature of the resistance-type temperature sensor is reduced. According to the invention, the anti-interference capability can be improved, and the measurement precision of 0.1 mK level can be reached near 273K.

A measurement system includes: a first laser device for outputting a pump light as a pulse laser in response to an input first signal; a second laser device for outputting a probe light as a pulse laser in response to an input second signal; a trigger generator and delay time controller for inputting the first signal and the second signal to the first laser and the second laser, repeatedly inputting the first signal and the second signal by switching a variable delay value which is a difference between a timing of inputting the first signal to the first laser and a timing of inputting the second signal to the second laser in a plurality of ways, and outputting a reference signal to a lock-in amplifier when switching the variable delay value; an auxiliary optical system for guiding the pump light and the probe light to sample; a cantilever having an probe tip disposed proximate to the sample; and a controller for applying a periodically varying voltage to the cantilever and outputting a change amount signal which is a voltage or a current corresponding to a change in the resonance frequency of the cantilever, wherein the lock-in amplifier measures the change amount signal based on reference signal.

The invention discloses a rheology-birefringence combined in-situ testing device and method based on chopper rotation frequency signals, belongs to the technical field of optical testing, and aims to solve the technical problems that an existing Spark-FB device is low in measurement accuracy and limits application scenes. The laser emitter emits a light beam along a set angle (forming an angle of 45 degrees with the horizontal plane), the light beam is converted into linearly polarized light through the polarizer, and an optical signal is modulated through the rotating chopper; the modulated light beam penetrates through a polymer sample to which a shear flow field is applied by a commercial rheometer, and transmission light carrying optical anisotropy information of the sample sequentially passes through a 1 / 4 wave plate and a polarization analyzer, and is finally received by a photoelectric detector and transmitted to a lock-in amplifier for analysis. According to the invention, an independent datum reference signal is provided through the chopper, decoupling and combination of a commercial rheometer and a birefringence light path are realized, and synchronous and accurate in-situ measurement of rheological and optical properties of a high polymer material under a deformation condition can be realized.

The invention relates to a Rydberg atomic communication receiving system and method based on AT split peak value analysis, and belongs to the technical field of quantum communication. The system comprises a detection laser, a coupling laser, an AOM / EOM, a function generator, a high-frequency signal generator, a cesium atom gas chamber, a photoelectric detector, a lock-in amplifier, a data acquisition module and a microwave signal output module. The AOM / EOM modulates the frequency of the detection laser; the microwave signal output module generates an AM modulation microwave signal and transmits the AM modulation microwave signal to the cesium atom gas chamber, so that the target Rydberg state atoms generate an AT splitting effect to calibrate system parameters; the photoelectric detector and the lock-in amplifier obtain a first harmonic component based on the transmission light. During communication, the system is arranged in a microwave electric field received by communication, and the data acquisition and processing module outputs AM modulation microwave signals received by the recovered cesium atom gas chamber based on calibrated system parameters and phase locking. The method solves the problem of signal distortion existing in EIT-AT direct communication transmission and the problem of tedious operation of a heterodyne method.

The invention relates to a resonant optical gyroscope signal detection method based on an optical switch. The resonant optical gyroscope signal detection method comprises the following steps: step 1, adopting a narrow linewidth laser as a light source; 2, the split light field enters a lithium niobate phase modulator A and a phase modulator B to be modulated by a triangular wave voltage signal, the light field subjected to phase modulation is coupled in opposite directions to enter a waveguide resonant cavity, and a photoelectric detector A and a photoelectric detector B are used at the output end of the resonant cavity to obtain a voltage signal; and voltage signals obtained by the photoelectric detector A and the photoelectric detector B are accessed to a lock-in amplifier. 3, arranging an optical switch A between the waveguide resonant cavity and the photoelectric detector A; and an optical switch b is arranged between the waveguide resonant cavity and the photoelectric detector B, so that the detection of a gyro signal is completed. The interference of polarization noise can be reduced, and the resonant frequency locking precision and the angular velocity detection sensitivity of the gyroscope are improved.

The invention discloses a bearing fault acoustic detection method and system based on fractional harmonic phase-locked amplification, and the method comprises the steps: obtaining an acoustic signal of a target motor, measuring the shaft rotation frequency of a motor shaft in real time, synchronizing the shaft rotation frequency to a fractional phase-locked loop, and carrying out the calculation of a bearing fault characteristic frequency according to the geometric parameters of a bearing, the bearing fault characteristic frequency is a non-integer multiple of the shaft rotation frequency, generating a reference signal synchronous with the bearing fault characteristic frequency through a fractional phase-locked loop, and performing phase sensitive detection on the obtained acoustic signal and the generated reference signal by using a phase-locked amplifier, specifically, performing orthogonal demodulation on the acoustic signal and the reference signal, and performing phase sensitive detection on the obtained acoustic signal and the reference signal. The method comprises the following steps: generating an in-phase component and an orthogonal component, extracting a direct-current component through low-pass filtering, calculating to obtain a vibration amplitude and phase information corresponding to a bearing fault characteristic frequency, and judging the type and severity of a bearing fault according to the comparison between the vibration amplitude and a preset baseline, the harmonic consistency and the phase stability.

The invention discloses a photoacoustic spectrum trace gas detection device and method based on a secondary demodulation technology. The device comprises a tunable laser, a laser collimation device, a focusing lens, a gas chamber, a quartz tuning fork resonance circuit, a first lock-in amplifier, a trigger capture circuit, a phase modulation circuit, a second lock-in amplifier and a control and signal acquisition device. In the aspect of automatic tracking of the frequency, the quartz tuning fork is integrated into an oscillator circuit, and automatic tracking of the laser modulation frequency is achieved. The oscillator circuit can automatically adjust the output according to the current resonant frequency of the quartz tuning fork, and ensures that the laser is always modulated at the optimal frequency. In the aspect of continuous phase modulation, traditional fixed phase setting is replaced, the phases of electric excitation and photoacoustic excitation are continuously modulated, and pure photoacoustic signals are separated by using two lock-in amplifiers, so that a complex phase calibration process is avoided, and the accuracy and stability of signal detection are improved.

The invention relates to the technical field of low-temperature infrared radiation detection, and provides low-temperature infrared radiation detection equipment, which comprises a vacuum cold box, an infrared detection device, a control system and a signal processing system, and is characterized in that the infrared detection device comprises an infrared window sheet, an optical shutter, an optical lens, an optical chopper and an infrared detector; the optical chopper adjusts an infrared radiation signal emitted by a target object to a predetermined frequency, and the infrared detector receives the infrared radiation signal and converts the infrared radiation signal into an electric signal; the signal processing system comprises a pre-amplifier, a lock-in amplifier, a signal processing unit and a display unit, the pre-amplifier amplifies the electric signals output by the infrared detector, and the lock-in amplifier extracts signals corresponding to the preset frequency from the electric signals amplified by the pre-amplifier and amplifies the signals. Through the arrangement, the optical chopper, the pre-amplifier and the lock-in amplifier are combined, so that the measurement precision of infrared detection is effectively improved.

The invention discloses an atomic force microscopic imaging device and method for a Josephson probe microscope, and belongs to the technical field of atomic force microscopic imaging. The device comprises a sample table, a second displacement assembly, a first displacement assembly, a superconductive Josephson probe assembly, a first controller, a second controller, a lock-in amplifier, a current amplifier and a high-speed data collector, the superconductive Josephson probe assembly comprises a probe module and a tuning fork module, and the probe module comprises a probe and a probe box. The tuning fork module comprises a tuning fork wafer and a substrate, the probe is connected with the tuning fork wafer, the lock-in amplifier is connected with the tuning fork wafer to monitor the amplitude change of the tuning fork wafer in real time, and the lock-in amplifier drives the sample to move up and down by controlling the second controller to realize closed-loop adjustment of the distance between the probe and the sample. The distance between the probe and the surface of the sample is adjusted in real time, the high stability in the imaging process is ensured, and the resolution is further improved; the service life of the probe can be effectively prolonged, and the use cost is reduced.

According to various embodiments, a sensing device for measuring oxygen concentration cycles in breath is disclosed. The sensing device includes a laser configured to emit light at an A-band of oxygen, a lens configured to collimate the light, and a multi-pass cell configured to contain a replaceable sample cell. The light passes through the multi-pass cell and is attenuated by oxygen in the sample cell. The sensing device further includes a photodetector configurated to convert the attenuated light into an electrical signal, and a lock-in amplifier or an equivalent processing circuit configured to determine oxygen concentration from the electrical signal.

The invention provides a biaxial coupling error suppression method of a nuclear magnetic resonance atomic gyroscope, and belongs to the technical field of nuclear magnetic resonance atomic gyroscopes. A nuclear magnetic resonance atomic gyroscope inertial measurement system is started, and a magnetic field is applied to the system, so that the system works in a nuclear magnetic resonance state; applying a low-frequency modulation magnetic field with a certain amplitude on a y axis orthogonal to the x axis, and outputting a measured magnetic field amplitude of the x axis under the condition by using a magnetometer embedded in the nuclear magnetic resonance atomic gyroscope; a PID module of a phase-locked amplifier in a system demodulation signal system is used as an input quantity of PID control, a target value is set as 0, an output quantity is set as a carrier demodulation frequency, and the suppression of coupling errors is realized by adjusting the carrier demodulation frequency to be consistent with an atomic frequency; when the nuclear magnetic resonance atomic gyroscope works normally, the alkali metal spin frequency is locked, it is guaranteed that the carrier demodulation frequency is consistent with the alkali metal spin frequency, additional auxiliary and calibration equipment does not need to be added, and the method has important significance in the field of inertial measurement.

The invention provides a light-induced force microscope system and an application method thereof. The system comprises a first laser, an atomic force microscope probe, a photosensitive detector, a first lock-in amplifier, a control box, piezoelectric ceramic, a second lock-in amplifier, a semiconductor laser, a light path system, a sample table, a piezoelectric scanning tube and a host. According to the light-induced force microscope system, the semiconductor laser is used, sine wave modulation is directly carried out on the semiconductor laser through the oscillator in the lock-in amplifier, and the light-induced force microscope system can accurately measure light force information at a needle point-sample position by using a common silicon needle point probe in the atmosphere. By analyzing the light force information, the light-induced force component can be qualitatively identified, and the rigidity, polarizability and other property information of the material can be reflected. According to the invention, accurate measurement of the light force signal on the surface of the two-dimensional material is realized, and a technology which is economical, simple in structure and convenient to operate is provided for identifying components and defects of the two-dimensional material in electronic devices, optoelectronic elements and sensors.

The utility model provides a spectral responsivity calibration device, and relates to the technical field of optical metrology. The device comprises a light source module, a light path module, a detection module, a control system and a packaging box, wherein the control system is respectively in communication connection with a light source, a light path and the detection module; the light source module is a direct-current voltage-stabilizing light source combined by a deuterium lamp and a halogen lamp; the light path module comprises an adjustable grating, a monochromator, a reflector and a lock-in amplifier, and the light path module is of a double-light-path design; the detection module comprises a reference detector, a standard detector and a detected detector. The standard detector is composed of a standard silicon detector, a standard indium gallium arsenic detector, a standard germanium detector and a standard lead sulfide detector. The device can be used for calibrating the spectral responsivity of ultraviolet, visible and near infrared detectors, and can be used for measuring and calibrating the spectral responsivity of the detected detector through a comparison method by arranging standard detectors such as silicon, germanium, indium gallium arsenic, lead sulfide and the like.

The invention discloses an all-optical-fiber liquid level measuring system and method based on double-optical-comb phase decoupling and self-adaptive compensation, and the system comprises a double-optical-comb light source module, an optical fiber coupling module, a signal collection and processing system, a self-adaptive compensation module, a measuring arm and a reference arm. The optical fiber coupling module comprises a polarization-maintaining optical fiber beam splitter and a polarization-maintaining optical fiber beam combiner; the signal acquisition and processing system comprises a balance detector, a lock-in amplifier and an upper computer which are sequentially connected from front to back, and the lock-in amplifier is connected with a self-adaptive compensation module; the double-optical-comb light source module is connected with the measuring arm and the reference arm through the polarization-maintaining optical fiber beam splitter, and the measuring arm and the reference arm are connected with the balance detector through the polarization-maintaining optical fiber beam combiner. According to the invention, interference signal intensity and phase information are combined, the problem of reflectivity difference between transparent liquid and opaque liquid is solved, phase noise caused by environmental disturbance is eliminated, and the measurement stability is improved. According to the invention, non-contact, real-time and high-resolution measurement of the height of the liquid level is realized, especially measurement in a high-pressure, high-temperature or corrosive environment is realized, and the application range is expanded.

The invention discloses a multi-mode nanometer measurement system and method based on terahertz scattering type scanning near-field optical microscopy and multi-frequency electrostatic force microscopy, and belongs to the technical field of near-field imaging, the measurement system comprises an AFM main body, a terahertz source, an optical path system, a terahertz detector, a multi-frequency signal generator and two phase-locked amplifiers; terahertz waves emitted by the terahertz source reach the terahertz detector through the optical path system, and near-field optical signals are obtained. The AFM comprises a metal coating probe; the multi-frequency signal generator generates sinusoidal signals with frequencies of omega1 and omega2; a sample is placed on the scanner, and the cantilever beam is controlled to vibrate at the frequency omega 1; an alternating voltage with the frequency of omega 2 is applied to a metal coating probe arranged at the top end of the cantilever beam; laser emitted by the laser is reflected to the light spot position detector through the cantilever beam, and morphology and electrostatic force signals are obtained through the two lock-in amplifiers respectively. According to the invention, a morphology signal, an optical signal and an electrostatic force signal can be synchronously obtained through single scanning.

The present disclosure relates to a method and device for removing background noise in microscopic imaging based on frequency-domain modulation. The method includes irradiating a surface of a sample to be measured by simultaneously irradiating the surface of the sample by utilizing two beams from two laser devices. One of the two beams passes through a 0˜2π vortex phase plate and then focuses on the sample to be measured to form a high-energy hollow spot, and the other of the two beams focuses on the sample to be measured to form a low-energy solid spot. The method further includes modulating the two beams in time-domain simultaneously using an electro-optic modulator and demodulating signal light at different frequencies using a lock-in amplifier, then removing the background noise by a differential process to realize a high signal-to-noise ratio super-resolution image.

A system for automatically locking a control laser in a Rydberg atomic sensor may comprise an atomic vapor cell, a probe laser configured to excite the atoms in the atomic vapor cell to an intermediate energy state, and a control laser configured to excite the one or more atoms in the atomic vapor cell from the intermediate energy state to a higher energy state. The light generated by the control laser may be dithered at a pre-determined frequency. The system further comprises a photodiode configured to convert light received from the vapor cell into an electrical signal, a lock-in amplifier configured to generate an error signal based on the electrical signal received from the photo diode and a received reference oscillation frequency, and a servo configured to receive the generated error signal from the lock-in amplifier and adjust a frequency of the control laser based on the received error signal.

The present invention relates to a high-altitude carbon fiber cable detection system and detection method. The high-altitude carbon fiber cable detection system includes a high-altitude carrying unit, a detection unit, a channel switching unit, an excitation signal amplification unit, a phase-locked amplifier unit, a main control unit, and an image reconstruction unit. The high-altitude carrying unit is used to carry the detection unit, so that the carbon fiber cable in the air can be detected. The high-altitude carrying unit can directly realize the placement and detachment of the detection unit, without the need for manual disassembly and installation, thereby improving the safety and convenience of the detection. After image reconstruction, a damage distribution image on the radial cross section of the inspected carbon fiber cable is obtained. The C-shaped frame of the detection unit can detect the notch position that cannot be detected before rotation by rotating. After image fusion, a complete damage distribution image on the radial cross section of the inspected carbon fiber cable is obtained.

The invention relates to the technical field of semiconductor laser control, and discloses an automatic frequency stabilization control system of a semiconductor laser, which comprises a lock-in amplifier used for demodulating a frequency discrimination signal; the modulation signal generator is used for outputting a sinusoidal signal or a cosine signal with the frequency of 100kHz and the peak-to-peak value of 40mV, and taking the sinusoidal signal or the cosine signal as a reference signal; the basic current and frequency sweep signal generator is used for adjusting the direct current offset, aligning a wave crest in a frequency discrimination error curve to a scanning midpoint, and outputting a sawtooth wave frequency sweep signal of which the peak value and the frequency can be adjusted; the PID controller is used for stabilizing the frequency discrimination signal to a saturation absorption peak corresponding value; and the automatic frequency stabilization state judgment and controller identifies a target saturated absorption peak through a two-stage peak searching algorithm, and locks the working frequency of the semiconductor laser on the frequency corresponding to the target saturated absorption peak. According to the invention, the operation process of the frequency stabilization system is simplified, and long-term stable operation of the semiconductor laser is ensured.

The invention discloses a TDLAS (Tunable Diode Laser Absorption Spectroscopy)-based gas concentration and temperature dual-parameter detection method and device, and the detection method comprises the following steps: 1, obtaining an optical signal passing through an absorption cell filled with gas to be detected, and converting the obtained optical signal into a digital signal to be detected; step 2, obtaining a fundamental frequency harmonic phase signal according to the digital signal to be measured and the two fundamental frequency reference signals; obtaining a second harmonic signal according to the digital signal to be measured and the two paths of frequency doubling reference signals; and 3, establishing an equation set of the fundamental frequency harmonic phase signal, the second harmonic signal and the gas concentration and temperature, and solving the equation set to obtain the gas concentration and temperature. According to the invention, the gas concentration and temperature signals are obtained through a simple method, the method can be used for replacing a lock-in amplifier, and the cost of a detection device and the system complexity can be effectively reduced.