49 results about "Digital intermediate frequency" patented technology

The invention relates to the technical field of array signal processing, in particular to a space-frequency power inversion anti-interference method fusing SMI-LDL decomposition. The problems that an existing space-time anti-interference technology is high in calculation complexity, and real-time processing is difficult to achieve in limited resources of a navigation receiver are mainly solved. The method comprises the following steps: firstly, converting a radio frequency signal received by an array into a digital intermediate frequency signal and carrying out sliding window partitioning processing; windowing the data block and performing FFT (Fast Fourier Transform) to obtain a frequency domain array; then calculating an auto-covariance matrix R of other array elements except the reference array element and a cross-covariance matrix r of the reference array element and other array elements; lDL decomposition is carried out on the auto-covariance matrix to obtain a lower triangular matrix L and a diagonal matrix D, and inversion is carried out on the lower triangular matrix L and the diagonal matrix D respectively, so that huge operand caused by direct inversion of the covariance matrix is avoided; and finally, calculating an optimal weighting vector according to a power inversion criterion, and performing spatial filtering on the frequency domain data.

The invention discloses a GNSS-R terminal baseband three-ring cooperative tracking method, system and device and a medium, and belongs to the technical field of satellite navigation signal processing, and the method comprises the steps: receiving a digital intermediate frequency BOC modulation satellite navigation signal; establishing a carrier tracking loop, a subcarrier tracking loop and a code tracking loop; performing frequency mixing operation on the digital intermediate frequency BOC modulation satellite navigation signal and a local carrier wave; performing correlation operation on the signal after the frequency mixing operation and a local subcarrier and a local pseudo-random code in sequence; carrying out accumulation processing on a correlation operation result to obtain a correlation accumulation value; respectively calculating error adjustment parameters of the carrier tracking loop, the subcarrier tracking loop and the code tracking loop based on the correlation accumulation values; and when the error adjustment parameters of the carrier tracking ring, the subcarrier tracking ring and the code tracking ring are all within a preset range, outputting navigation data. According to the invention, the problem that a traditional double-ring method cannot fully utilize subcarrier components is solved.

The invention discloses a carrier ring auxiliary code delay phase-locked loop tracking method, system and device and a medium, and belongs to the technical field of signal tracking, and the method comprises the steps: obtaining a digital intermediate frequency signal, and constructing a code loop model; executing code tracking through the code loop model to obtain a code phase error measurement value, and determining a relationship between a carrier-to-noise ratio and a noise covariance; a measurement noise covariance matrix model is obtained through combination of a code phase error measurement value and a carrier-to-noise ratio dynamic state and is used for first adjustment of a filter. According to the invention, a measurement noise covariance matrix is dynamically adjusted based on real-time carrier-to-noise ratio estimation, so that the filter can accurately adapt to signal quality change, fully trust an accurate measurement value when a signal is strong, greatly reduce tracking jitter, achieve higher pseudo-range measurement precision, and automatically reduce dependence on the measurement value under noise interference when a signal is weak. In turn, the method depends on smooth prior model prediction.

In a general aspect, a magnetic resonance system performs a magnetic resonance measurement. In some examples, a magnetic resonance system includes data processing apparatus and a superheterodyne spectrometer system. The data processing apparatus generates digital intermediate frequency (IF) signal information based on a pulse profile. The digital IF signal information is configured to suppress an image sideband in a magnetic resonance control signal. The superheterodyne spectrometer generates the magnetic resonance control signal based on the digital IF signal information.

The invention discloses a service-adaptive satellite-borne non-uniform multicarrier demodulation device, and belongs to the field of digital signal processing. The method comprises the following steps of: firstly, performing orthogonal down-conversion and resampling filtering processing on a digital intermediate frequency signal sampled by an ADC (Analog to Digital Converter), processing the digital intermediate frequency signal by a non-uniform channelization splitter, and then serially outputting the digital intermediate frequency signal to a spread spectrum ratio self-adaptive variable burst capturer according to fixed quadruple sampling to capture a leading head and identify the spread spectrum ratio; the method comprises the following steps: completing symbol synchronization and de-spreading processing on an input signal according to a spread spectrum ratio, then completing carrier coarse synchronization and pattern word identification, completing modulation mode identification and carrier synchronization according to a pattern word, performing channel decoding through a multi-mode decoder to recover to an information bit stream, and outputting the information bit stream. And the information bit stream is sent to a service frame recombination processor for search identification and recombination splicing, and output is carried out after whole-frame CRC check is carried out. The method has the advantages of flexibility in use, low resource occupation and capability of realizing adaptive demodulation of variable-rate, multi-modulation-mode and multi-coding-mode service transmission signals without parameter configuration.

The invention relates to a self-adaptive pulse interference suppression method and device, computer equipment and a storage medium. The method comprises the following steps: carrying out sliding window energy detection on a digital intermediate frequency signal output by the front end of a satellite navigation receiver to obtain a pulse interference duty ratio, carrying out FFT (Fast Fourier Transform) on an interference time period signal to extract an effective bandwidth, establishing a carrier-to-noise ratio loss estimation model of two strategies of time domain zero setting and frequency domain spectral line elimination, substituting parameters to calculate a loss value, and calculating the loss value according to the carrier-to-noise ratio loss estimation model. And preferentially executing interference suppression. According to the method, intelligent adaptation of an interference suppression strategy is realized, carrier-to-noise ratio loss is minimized, the robustness and availability of a receiver in a complex electromagnetic environment are improved, the algorithm compatibility is high, engineering integration is easy, and the method has the expansion potential of combining machine learning optimization.

The invention discloses a DPE / INS quasi-deep combination method and system in a GNSS navigation domain, and the method comprises the steps: collecting a GNSS digital intermediate frequency signal through a hardware platform radio frequency front end of a GNSS receiver, inputting a local signal and the digital intermediate frequency signal into a correlator after determining a parameter search range of a local copied signal, and obtaining a PVT estimation result and covariance of a DPE receiver through maximum likelihood estimation; meanwhile, the PVT estimation result and covariance of the INS at the current moment are calculated through inertial navigation calculation, and the PVT estimation result and covariance of a DPE / INS combined system are obtained through combined filtering of the PVT estimation result and covariance of the DPE receiver and the INS and used for determining the parameter search center, the search range and the search step length of a local copy signal of the DPE receiver; a series of local replication signals are then determined. According to the method, the function of the INS sensor in the navigation domain of the DPE receiver is determined by utilizing the characteristic that the INS is not interfered by the environment, an interaction mechanism of the INS auxiliary information in the related domain and the navigation domain is established, and the interaction mechanism is named as a quasi-deep combination according to the characteristics of the architecture, so that the DPE receiver is effectively helped to narrow the search range and improve the precision.

In a general embodiment, a magnetic resonance system performs magnetic resonance measurements. In some examples, the magnetic resonance system includes a data processing unit and a superheterodyne spectrometer system. The data processing unit generates digital intermediate frequency (IF) signal information based on the pulse profile. The digital IF signal information is configured to suppress image sidebands in the magnetic resonance control signal. The superheterodyne spectrometer generates the magnetic resonance control signal based on the digital IF signal information.

The application provides a multi-modal fusion radar tide intelligent adaptive filtering method, and belongs to the technical field of radar tide.The application collects dual-polarized radar signals, performs three-layer wavelet decomposition on vertical and horizontal polarization digital intermediate frequency signals, and marks clutter coefficients based on variance and skewness threshold values, performs adaptive soft threshold processing, and utilizes a convolutional neural network to evaluate residual clutter confidence and dynamically adjust suppression strength, calculates a polarization phase difference sequence and inputs a long short-term memory network to identify false target distance units, combines ray tracing calculation of a digital elevation model to calculate multipath path parameters for phase compensation and amplitude correction, and finally detects real tide height distance Doppler spectrum peak values to obtain accurate tide height values, thereby solving the technical problem that radar tide measurement in a complex marine environment cannot effectively distinguish clutter interference and multipath false targets, resulting in a decrease in measurement accuracy.

The application discloses a chip verification platform based on FPGA and a verification method thereof, and the platform comprises an FPGA core configured to realize prototype logic of a chip to be verified and perform digital signal processing, an intermediate frequency input module, a system clock configured to guarantee timing synchronization of modules of the platform, an external interface configured to support communication verification between the chip to be verified and external equipment, and a debugging interface configured to realize signal monitoring and problem positioning of a verification process; the intermediate frequency input module is configured to receive an analog intermediate frequency signal output by a radio frequency front end and provide a compliant intermediate frequency signal source for verification; the intermediate frequency input module comprises a Balun unit, an ADC unit and a CPLD data distribution module connected in sequence; the CPLD data distribution module completes adaptation and distribution of a digital intermediate frequency signal by dynamically switching a data transmission path and controlling a priority of multi-channel data. The chip verification efficiency and reliability are improved.

The invention discloses a method for realizing dual-polarization phased array weather radar target simulation by using a digital receiver, and relates to the technical field of radar signal processing. According to the method for realizing dual-polarization phased array weather radar target simulation by utilizing the digital receiver, a weather target micro-physical parameter model is established, abundant FPGA resources in the phased array radar digital receiver are combined, and a similar direct digital frequency synthesis (DDS) technology is utilized, so that a high-fidelity digital intermediate frequency echo signal is generated; dynamic target simulation is realized in an active array digital receiver of a phased array radar. Controllable and repeatable simulation of various weather phenomena (rain, snow, hail and the like) can be realized in a laboratory environment. Under the condition of not depending on external hardware, echo characteristics of weather targets (such as rainfall particles), including parameters such as distance, speed, amplitude and dual-polarization parameter quantity, are simulated, and debugging, performance verification and algorithm testing of a radar system are effectively supported.

The application provides a signal modulation mode recognition method and system based on time-frequency domain image matching, and belongs to the technical field of signal processing. The method comprises the following steps: obtaining a signal data set, which contains M types of signals with different signal system modes, and each type contains N signals; performing time-frequency analysis on the M*N signals respectively to obtain M*N time-frequency power spectrum matrices and generate M*N signal time-frequency domain images; dividing the M*N signal time-frequency domain images into a training set and a test set according to a proportion to train a recognition classifier based on a neural network; obtaining a received radio frequency signal to be recognized, performing down-conversion processing on the radio frequency signal to obtain a digital intermediate frequency signal, and generating a signal time-frequency domain image of the digital intermediate frequency signal; and using the trained recognition classifier to match the signal time-frequency domain image of the digital intermediate frequency signal with the M*N signal time-frequency domain images to obtain a recognition result of the signal modulation mode of the radio frequency signal to be recognized.

The embodiment of the invention provides a transmitting device, a receiving device, a system and a method of a terahertz wireless communication system, and the method comprises the steps: generating an initial signal modulation symbol based on an initial random bit sequence, and generating a transmitting end digital intermediate frequency signal based on the initial signal modulation symbol; converting the transmitting end digital intermediate frequency signal into a transmitting end analog intermediate frequency signal; generating a terahertz signal according to the local oscillator signal and the transmitting end analog intermediate frequency signal; generating a receiving end analog intermediate frequency signal according to the terahertz signal and the local oscillator signal, and converting the receiving end analog intermediate frequency signal into a receiving end digital intermediate frequency signal; and processing the digital intermediate frequency signal of the receiving end to obtain a baseband signal, processing the digital baseband signal to obtain a carrier phase synchronization digital signal, and processing and demapping the carrier phase synchronization digital signal based on the sliding window bidirectional LSTM neural network to obtain a target random bit sequence. Nonlinear distortion caused by a terahertz device in terahertz communication is relieved, and EVM is reduced.

This invention belongs to the field of antenna signal processing technology, specifically relating to a method and system for optimizing multi-frequency antenna signals based on data processing. The method includes the following steps: acquiring the digital intermediate frequency (IF) signal of the multi-frequency antenna; calculating the target band power spectral density and frequency cross-correlation matrix of the IF signal; calculating the power distribution data of adjacent band interference; determining the filter order of the discrete-domain digital transfer function based on the spectral entropy value of the target band power spectral density; identifying key frequency intervals within the passband based on the frequency cross-correlation matrix; setting strict passband ripple constraints; and setting high attenuation target values ​​for high-interference frequency points in the stopband based on the power distribution data of adjacent band interference. The discrete-domain digital transfer function generated by this invention can filter the multi-frequency antenna signal, ensuring high-fidelity transmission of the passband signal while filtering out adjacent band interference, thus improving the overall signal communication quality of the multi-frequency antenna.

The invention belongs to the field of satellite navigation, and particularly relates to a space-frequency anti-interference method based on self-adaptive null broadening, which comprises the following steps: converting a digital intermediate frequency signal into a frequency domain signal through windowing and discrete Fourier transform, and calculating a covariance matrix in a conventional operation scene; the Doppler change rate is adopted to identify a current motion scene, so that whether matrix reconstruction is carried out or not is judged, and an adaptive null broadening function is realized; and performing spatial filtering on each narrow sub-band, and transforming a frequency domain signal back to a time domain signal by using inverse discrete Fourier transform and inverse window to obtain anti-interference data. According to the method, the Doppler change rate is innovatively introduced into null broadening for self-adaptive judgment, the problem of mismatching of the null depth and the interference coming direction in special motion scenes such as a large off-axis attitude is solved, meanwhile, the anti-interference limit performance in a conventional operation scene is not affected, and the self-adaptive capacity of the anti-interference navigation terminal is effectively improved.

The application relates to a GNSS high-sensitivity acquisition method and equipment applied to a deep space spacecraft. The core process of the method is as follows: the time and corresponding position of receiving GNSS signals by the spacecraft are acquired, the satellite position at the receiving time is calculated by combining the pre-stored target satellite orbit information, and the signal transmission time is obtained through iterative correction; the starting time of digital intermediate frequency data storage is determined according to the subframe period of the navigation message, so that the key specified bits of the message are completely contained, and the navigation message is stripped by using the fixed and predictable bits; the Doppler center frequency offset is obtained by calculating the relative speed of the line-of-sight direction between the star and the earth, the search range is determined by combining the speed uncertainty, the signal acquisition is completed in the limited range, and the code phase and the carrier frequency offset are solved. The application is suitable for the scene that the deep space signal is weak, the propagation time delay is long, and the Doppler characteristic is complex, the position mismatch error is avoided through iterative correction, a high-precision time reference is acquired, and the GNSS signal acquisition performance is significantly improved.

The invention discloses a digital down-conversion method based on full digital domain processing, which relates to the technical field of signal processing, and comprises the following steps: down-converting an input digital intermediate frequency signal to a zero intermediate frequency position by adopting a frequency mixing mode according to the input digital intermediate frequency signal; performing multi-stage filtering extraction on the signal after frequency conversion processing; and resampling is carried out, and the sampling rate of the signal is changed to adapt to a subsequent signal processing module. According to the invention, the requirement of any multiple sampling rate conversion at the rear end of equipment can be met.

The invention discloses a method and a system for suppressing an image frequency of a receiver, and relates to the technical field of radio frequency microwave communication, and the method comprises the following steps: receiving a first digital intermediate frequency signal which is obtained by performing frequency mixing output on a radio frequency input signal and a local oscillator signal by a frequency mixer and then performing analog-to-digital conversion on the radio frequency input signal and the local oscillator signal; the first numerical value intermediate frequency signal corresponds to a first local frequency; performing signal processing on the first digital intermediate frequency signal, and obtaining a first frequency mapping result through FFT operation; performing fine tuning on the first local frequency by a preset offset to obtain a second local frequency, obtaining a corresponding second numerical value intermediate frequency signal based on the second local frequency, performing signal processing on the second digital intermediate frequency signal, and performing FFT operation to obtain a second frequency mapping result; and comparing the first frequency mapping result with the second frequency mapping result, identifying and rejecting the mirror image frequency signal, and effectively discriminating and rejecting the mirror image interference signal.

The invention belongs to the technical field of global satellite navigation system signal processing, and particularly relates to a code tracking method and system for joint multi-frequency signals, and the method comprises the steps: carrying out the filtering, amplification, coherent integration and code discrimination of received signals of a plurality of frequency points, the digital intermediate frequency signals corresponding to the received signals and the code delay error estimation values thereof can be accurately obtained; the target weight of each code delay error estimation value is determined through the acquired variance of the target estimation error value of each digital intermediate frequency signal, and then weighted fusion can be performed on each code delay error estimation value based on each target weight to obtain common-mode code phase output and differential-mode code phase output with higher precision. Therefore, the target code rate correction amount of the inter-frequency deviation corresponding to each received signal can be accurately obtained, and each inter-frequency deviation is dynamically corrected, so that the code tracking precision of the joint multi-frequency signal is effectively improved.

The invention relates to the field of channel blind equalization, and provides an adaptive blind equalization method and device based on channel perception, and the method comprises the steps: obtaining a digital intermediate frequency signal; performing channel feature extraction on the digital intermediate frequency signal to obtain a channel feature parameter; mapping the channel characteristic parameters to obtain pre-equalization parameters and initial working mode suggestions; comprehensive decision processing is carried out according to the pre-equalization parameters, the initial working mode suggestion and error signals, a dynamic weighting factor is obtained, and the error signals comprise error signals output by the equalizer in real time; performing signal conditioning and distortion correction processing according to the dynamic weighting factor to obtain a baseband signal; according to the method, through the synergistic effect of the technical means, signal conditioning and distortion correction are finally carried out by utilizing the dynamic weight, the baseband signal is accurately recovered, and system parameters are continuously optimized through closed-loop adaptive adjustment.

The invention discloses a device for detecting burst signals of a navigation management receiving channel, and relates to the technical field of navigation management application. The equipment comprises a field programmable gate array (FPGA) which is connected with an analog-to-digital converter of the navigation management equipment and used for processing digital intermediate frequency signals output by the analog-to-digital converter of the navigation management equipment so as to obtain time domain information and frequency domain information of burst signals in the digital intermediate frequency signals, and the FPGA is the FPGA of the navigation management equipment; and the display module unit is connected with the FPGA and is used for receiving and displaying the time domain information and the frequency domain information of the burst signal. According to the method, the receiving channel problem can be quickly positioned by design and testing personnel, and the receiving channel signal monitoring efficiency is improved.

The invention belongs to the technical field of digital signal processing in a radio frequency / microwave communication system, and particularly discloses a multi-frequency parallel compensation method for a nonlinear phase of a radio frequency device, which is characterized by comprising the following steps of: S1, acquiring a phase-frequency curve p (f) of an output signal of a radio frequency end of the radio frequency device; s2, converting the phase frequency curve p (f) into a plurality of amplitude-frequency responses amp (f), performing inverse Fourier transform on the amp (f) to generate a filter coefficient hp, and performing M-order truncation and N-bit fixed-point quantization on the hp to generate an all-pass filter coefficient hp (m); s3, performing orthogonal down-conversion on a digital intermediate frequency signal y (n) to be compensated to a baseband, inputting the digital intermediate frequency signal y (n) into the all-pass filter, and simultaneously completing phase compensation on all frequency components contained in the y (n) by utilizing a group delay characteristic; and the compensated baseband signal is recovered to the original intermediate frequency through quadrature up-conversion, and an output signal with a corrected nonlinear phase is obtained. Phase modulation can be carried out on multiple frequency signals at the same time, frequency measurement is not needed, and frequency and data alignment does not need to be considered.

The invention discloses a digital intermediate-frequency coherent Doppler wind-finding radar system, and relates to the field of wind-finding radars, in particular to a compact laser wind-finding radar system based on optical fiber optics design, which comprises a transmitting unit, a digital intermediate-frequency coherent receiving module and an upper computer unit, the digital intermediate-frequency coherent receiving module receives backward echo signals scattered by aerosol particles in the atmosphere in a digital intermediate-frequency coherent receiving mode and performs preliminary signal conditioning, and the upper computer unit accurately extracts Doppler frequency shift information by applying a digital signal processing algorithm, so that the wind speed and the wind direction are calculated; and the system is responsible for coordinating the work of each unit and realizing the automatic operation of the system. By optimizing the optical module, the digital intermediate frequency coherent receiving mode and the signal processing algorithm, the wind measurement precision and reliability are improved, the system complexity is reduced, and the wide application prospect is achieved.

The invention discloses a satellite mobile communication system multi-broadcast frequency point parallel search method and device, and the method comprises the steps: obtaining a satellite digital intermediate frequency signal containing a plurality of target frequency bands, carrying out the digital down-conversion processing of the intermediate frequency signal through employing multiple channels, obtaining a baseband signal corresponding to each target frequency band, and transmitting the baseband signal to a receiver; performing cross-correlation operation on the baseband signal after downsampling and filtering processing and a local broadcast signal; and performing frequency domain transformation on a cross-correlation operation result, determining the maximum amplitude and the signal-to-noise ratio in the frequency domain data of each channel, screening the effectiveness of each channel according to the signal-to-noise ratio, and determining the position of the satellite by taking the beam direction corresponding to the maximum amplitude in the effective channel as the incoming wave direction of the broadcast signal. The real-time performance of signal searching in the multi-frequency-point environment is improved, the high signal detection capacity and anti-interference performance are shown in the complex electromagnetic environment, and the method has the advantages of being small in resource consumption, high in operation speed, stable in searching result and good in universality.

This invention discloses an adaptive interference suppression method and system based on spectrum analysis, belonging to the field of radar signal interference suppression technology. The method includes: acquiring multiple digital intermediate frequency (IF) interference signals; performing spectrum analysis on each IF interference signal to obtain signal spectrum analysis results; adjusting the sub-band filter structure based on the signal spectrum analysis results to ensure that the number of interference signals within any sub-band satisfies interference suppression; inputting each IF interference signal into the adjusted sub-band filter to obtain corresponding multi-channel sub-band signals; inputting each sub-band signal into an adaptive interference suppression structure, and using the signal spectrum analysis results for the initial calculation of the optimal weight vector to obtain a synthesized signal. This invention performs spectrum analysis on the interference signal and adaptively modifies the parameters of various interference suppression parameters based on the spectrum analysis results, thereby achieving optimal interference suppression effect with fixed hardware resource consumption.

This application provides a satellite navigation signal tracking method, apparatus, electronic device, and readable storage medium. The method includes: generating a local satellite navigation signal based on a lookup table and current multi-branch local satellite navigation signals; performing calculations on the local satellite navigation signal and a digital intermediate frequency (IF) satellite navigation signal to obtain multiple energy values; accumulating the multiple energy values ​​and inputting the accumulation result into a carrier loop and / or a code loop; and tracking the satellite navigation signal based on the carrier loop and / or the code loop. This application generates a local satellite navigation signal using a lookup table and current multi-branch local satellite navigation signals, and then inputs the signal into a carrier loop and / or a code loop after a series of calculations on the local satellite navigation signal and the IF satellite navigation signal. This allows for tracking of satellite navigation signals with sufficient front-end bandwidth. The entire tracking method has low complexity, simple processing, and is easy to implement.

The invention discloses a dual-mode satellite-borne base station device supporting NTN / cellular terminal direct connection satellites, which adopts a multi-beam structure, and each beam can be configured to access an NTN system terminal or access a cellular terminal direct connection satellite. The device comprises a baseband processing module which operates a dual-mode physical layer, comprises an event processing unit, a computing unit, a radio frequency driving unit and a data transfer unit, and is switched to an NTN physical layer mode or a physical layer mode directly connected with a cellular terminal through MAC layer configuration; the heterogeneous protocol stack module runs an NTN protocol stack and / or a satellite-borne protocol stack directly connected with a cellular terminal; the radio frequency front-end module adopts a broadband digital intermediate frequency architecture, covers an NTN frequency band and a cellular frequency band, and realizes multi-frequency-band parallel processing; and the beam resource management module is used for dynamically allocating the number of beams serving the NTN terminal and the number of beams serving the cellular terminal according to the number of terminal users. The method has the characteristics of high flexibility and high compatibility, and is suitable for satellite communication, a space-ground integrated network and a heterogeneous networking scene.

The invention relates to the technical field of radio frequency signal receiving and transmitting equipment, and discloses a low-cost miniaturized digital intermediate frequency receiving and transmitting front end based on an SIP (Session Initiation Protocol) module, which comprises a transmitting unit, a local oscillator unit and a receiving unit, the transmitting unit receives signal input from the digital signal processing unit for transmitting, and the receiving unit outputs the received signal to the digital signal processing unit; a transmitting intermediate frequency module and a transmitting SIP module are arranged in the transmitting unit. Through SIP modular design, a large number of radio frequency bare chips are integrated in a tube shell, the integration level of the assembly can be greatly improved, meanwhile, the self-shielding characteristic of metal ceramic BGA packaging is utilized, a metal partition wall occupying a large space in a traditional microwave assembly can be omitted, and the space of the assembly is greatly saved.

The application discloses a high-precision RCS measurement method and device based on a navigation radar intermediate frequency signal, and the method comprises the following steps: acquiring a working parameter information set of a navigation radar and intermediate frequency analog signal output port information; based on the working parameter information set and the intermediate frequency analog signal output port information, a digital intermediate frequency signal is collected; and the digital intermediate frequency signal is processed to obtain a target RCS value.

After an unnecessary band component is removed from an intermediate frequency (IF) demodulated signal obtained through IF demodulation of an observation signal of nuclear magnetic resonance, a digitization device (21) generates a magnetic field or the like corresponding to the IF demodulated signal, generates light corresponding to the magnetic field or the like by using a sensing member in an optical quantum sensor unit, converts the light to a sensor signal by using a photoelectric element, and digitizes the sensor signal by using an A / D converter to generate a digital IF demodulated signal. The optical quantum sensor unit has unstable output intensity characteristics in a prescribed frequency range. A correction processing unit (22b) corrects the IF demodulated signal in accordance with the frequency of the magnetic field or the like so that the frequency characteristics of the IF demodulated signal in the aforementioned frequency range are brought close to a constant value.