137 results about "Frequency mixing" patented technology

The invention provides a laser radar ranging method based on parallel detection, which relates to the technical field of laser radar ranging, and comprises the following steps: generating N lasers with different wavelengths, splitting beams by a beam splitter, separating optical channels with N independent wavelengths by a demultiplexer, performing frequency shift processing, combining N paths of optical signals after frequency shift through a beam combiner, and combining the N paths of optical signals after frequency shift through a beam splitter; generating a beam of composite reference light containing N wavelengths, wherein each wavelength has a specific frequency shift; signal light returned from a target and the composite reference light are jointly input into a coupler for frequency mixing so as to generate an optical beat frequency signal, and operation processing is performed to calculate the target distance and the target radial speed corresponding to each wavelength. According to the laser radar ranging method provided by the invention, parallel detection of the laser radar can be realized, beat frequency signals corresponding to a plurality of different wavelengths can be distinguished only by integrating a group of detectors, a cross-group amplifier and an analog-to-digital converter, the cost is greatly reduced, and the complexity of the system is reduced.

A non-contact real-time monitoring system of physiological signs based on millimeter-wave radar includes a millimeter-wave radar and multiple modules for processing radar signals. The millimeter-wave radar is configured to continuously transmit electromagnetic wave signals and simultaneously receive echo signals, perform frequency mixing processing on the echo signals to obtain an intermediate frequency signal, and process the intermediate frequency signal to obtain a radar four-dimensional data matrix. Human body physiological signs are monitored by analyzing body thoracic cavity micro-motion information in signals through the modules; a target echo is processed by adopting a constant false alarm rate detection algorithm, and invalid signals are filtered. A self-adaptive range cell selection algorithm based on short-time stability of respiratory signals is adopted to capture radar echoes reflecting physiological movement. Mixed human body physiological sign signals are processed by using a VMD algorithm, and key parameters in VMD are optimized by using a GWO algorithm.

The invention discloses a DP-MZM-based reconfigurable mixer with phase shift and image rejection functions, and belongs to the field of microwave photon signal processing. By adjusting an input radio frequency signal and a direct current bias voltage of the DP-MZM1, four different LO frequency doubling and mixing functions can be realized. By controlling the angle alpha between the polarization direction of the polarization analyzer and one axis of the modulator, the phase of the generated signal can be flexibly tuned in the range of 0-360 degrees. When combined with the optical frequency comb, the multi-channel multi-band frequency conversion system can be expanded into a multi-channel multi-band frequency conversion system with independent phase tuning capability by utilizing the channel switching and frequency slot selection functions of the wavelength selection switch, and parallel output of various frequency mixing results can be realized. By adjusting the phase difference between the two-channel output signals, I / Q mixing, double-balanced mixing and image rejection mixing can be configured. The scheme is not influenced by direct current bias drift, the system complexity is reduced, and the frequency conversion efficiency is improved.

The invention discloses a gesture recognition method and system based on an active acoustic sensing field, and the method comprises the steps: transmitting a frequency modulation continuous wave through a loudspeaker on head-mounted equipment, and receiving an echo signal reflected by the hand of a wearer through a microphone on the head-mounted equipment; performing frequency mixing, low-pass filtering and analog-to-digital conversion on the echo signal to obtain a digital baseband signal; performing range correction and noise reduction processing on the digital baseband signal to obtain a hand echo signal; inputting a hand echo signal into the multi-scale time sequence encoder, and capturing long time sequence dependence to obtain multi-scale spatial-temporal characteristics; performing trajectory tracking on the multi-scale spatial-temporal features by the hand key point regression branches to obtain hand key point features; inputting the hand key point features and the multi-scale spatial-temporal features into the gesture recognition branch to obtain a gesture recognition result; according to the method, multipath interference and spatial fuzziness in the acoustic sensing process can be overcome, and high-precision and fine-grained gesture recognition is realized.

The invention discloses a planetary atmospheric trace gas spectrum telemetering and in-situ fusion detection system and method, and belongs to the technical field of deep space exploration. The detection system has a telemetering mode and an in-situ detection mode, and comprises a telescope module, a laser light source module, a heterodyne spectrum telemetering module, an in-situ absorption spectrum module, a gas sampling and enriching module and a signal acquisition, processing and control module. In the on-orbit stage, a heterodyne spectrum telemetering module is adopted, and a laser light source and sunlight signals are subjected to frequency mixing for atmospheric component telemetering; and after the detector enters an atmospheric descending section, the in-situ absorption spectrum module performs in-situ absorption spectrum measurement by utilizing the detection light of the same laser light source. By performing space-time fusion and joint inversion on the data acquired in the two modes, coherent detection from large-range general survey to fixed-point detailed survey is realized, the problems of load separation of telemetering and in-situ detection and difficulty in data fusion are solved, and the detection efficiency, the data consistency and the integration level of the system are greatly improved.

The invention relates to a low-noise high-precision pressure measuring circuit which comprises a bridge type sensor, an alternating-current excitation signal source, a phase-sensitive detector, a low-pass filter, a reference signal source and a signal conditioning amplifier. The alternating current excitation signal source modulates a differential voltage signal generated by the bridge type sensor to a high-frequency alternating current excitation signal generated by the alternating current excitation signal source to obtain a high-frequency pressure signal; the high-frequency pressure signal is amplified by the signal conditioning amplifier to form a modulated signal; the phase-sensitive detector performs frequency mixing on the modulated signal and a reference signal generated by a reference signal source to obtain a frequency mixing signal; the frequency mixing signal is filtered by a low-pass filter to form a direct-current voltage signal for pressure measurement; the reference signal generated by the reference signal source and the high-frequency AC excitation signal generated by the AC excitation signal source have the same frequency. According to the circuit, signals are modulated to a high-frequency area with low noise energy to be processed by adopting alternating-current excitation and coherent detection technologies, the signals and noise are effectively separated, and extremely high measurement resolution and precision are achieved.

The invention relates to the technical field of signal generation, and discloses a signal generation system and method, and the system comprises a first signal generation module; the second signal generation module comprises an analog signal generation unit and a signal copying unit; the signal mixing module comprises an analog frequency mixing unit, a digital frequency mixing unit and a signal switching unit; the output end of the analog signal generation unit is connected with the input end of the analog frequency mixing unit; the first end of the signal copying unit is connected with the clock signal output end of the analog signal generating unit, the second end is connected with the mixing input end of the analog signal generating unit, and the third end is connected with the first end of the signal switching unit; the second end of the signal switching unit is connected with the output end of the analog frequency mixing unit, and the third end is connected with the input end of the digital frequency mixing unit. Therefore, a direct digital frequency synthesizer in the analog signal generation unit is calibrated when the clock signal is switched to, and spurious signals are eliminated based on a calibration result when the clock signal is switched to the analog local oscillator signal.

A spectral linewidth adjusting method includes: adjusting a timing of a first trigger signal for amplifying and converting a portion of a first pulse laser beam to a second pulse laser beam and / or a timing of a second trigger signal for amplifying and converting a portion of second continuous light to a third pulse laser beam and adjusting a spectrum of a fourth pulse laser beam obtained by performing sum-frequency mixing of the second and third pulse laser beams to a first spectrum in a non-Gaussian shape; and modulating a wavelength of the second continuous light within time corresponding to one pulse of the third pulse laser beam and adjusting the spectrum of the fourth pulse laser beam to a second spectrum having a spectral linewidth wider than the first spectrum through generation of a modulation signal for supplying the modulation signal to an optical phase modulator.

The invention discloses an in-vitro liquid level measurement method and device based on millimeter wave radar and a medium, and relates to the technical field of liquid level measurement, and the method comprises the steps: collecting geometric parameters of a container, building a container coordinate system, and forming static background data; the millimeter wave radar array is controlled to radiate millimeter wave signals in sequence, a receiving channel receives reflection echoes, amplification, frequency mixing, filtering and sampling processing are carried out, and array time sequence data are obtained; according to the array time sequence data, generating a distance direction frequency spectrum data set, combining static background data to carry out background deduction, executing an incident direction estimation algorithm, obtaining scattering point cloud under a container coordinate system, and generating a liquid level two-dimensional contour; based on the two-dimensional contour of the liquid level and the geometric parameters of the container, effective bottom surface grids are screened, the estimated value of the liquid volume in the container is obtained and converted into the equivalent liquid level height, and the final liquid level height is obtained. The two-dimensional fluctuation form of the liquid level is finely described, and the liquid volume and liquid level height measurement precision is improved.

The invention discloses a signal reading system and method for superconducting microwave multiplexing device detection, and belongs to the field of superconducting microwave multiplexing device detection, and the system comprises a server which can issue a detection configuration instruction to a signal board, receive and return detection data, operate detection software, execute spectrum analysis and data analysis, and generate a detection result; the signal board is provided with a circuit containing a programmable logic device, and the circuit can output accurate intermediate frequency signals and excitation current signals according to instructions of the server, processes output signals of the detected superconducting microwave multiplexing devices mixed by the frequency mixing board through a critical sampling filter bank algorithm to obtain detection data, and transmits the detection data back to the server; and the frequency mixing plate can perform up-conversion on the intermediate frequency signal generated by the signal plate to radio frequency to form a radio frequency detection signal, output the radio frequency detection signal to each detected superconducting microwave multiplexing device, perform down-conversion on the radio frequency response signal returned from each superconducting microwave multiplexing device to intermediate frequency, and output the radio frequency response signal to the signal plate. The system can detect the quality of the device with low computing resources.

The utility model provides a phase-locked loop circuit, which relates to the technical field of phase-locked loops and comprises a reference frequency multiplication filtering unit, an auxiliary mixing frequency-locked phase loop unit and a main mixing frequency-locked phase loop unit. The reference frequency multiplication filtering unit is used for receiving the first reference signal, performing frequency division processing on the first reference signal, performing frequency multiplication filtering on one path of signal after frequency division processing, and outputting a low-phase noise signal; the auxiliary frequency-mixing phase-locked loop unit is used for receiving the low-phase noise signal output by the reference frequency-doubling filtering unit and the other path of signal obtained by frequency division of the reference frequency-doubling filtering unit, and outputting an LO reference signal after frequency mixing and phase discrimination; and the main frequency mixing phase-locked loop unit is used for receiving the second reference signal and the LO reference signal output by the auxiliary frequency mixing phase-locked loop unit, and outputting a coherent signal after frequency mixing and phase discrimination. According to the utility model, the LMX2820 is used as the phase discriminator, the phase detection range is small, the locking detection can be easier, and the practicability is strong.

The invention discloses a small-sized wide instantaneous bandwidth radio frequency receiving front-end SiP module based on an HTCC, and belongs to the technical field of microwaves and radio frequency. The radio frequency receiving front end is realized on the basis of an SiP module of the HTCC, the mirror image frequency is far away from the radio frequency signal frequency spectrum through a high local oscillator dual-frequency conversion mode, and the spurious component generated by frequency mixing is moved to a high-frequency area outside an intermediate-frequency passband, so that wide instantaneous bandwidth and high spurious suppression are realized. According to the invention, miniaturization of the SiP module is realized based on the HTCC technology; a secondary frequency conversion superheterodyne circuit architecture and a high local oscillator design are combined, so that the instantaneous working bandwidth is widened to 4GHz, and meanwhile, high spurious suppression is realized; in addition, the vertical interconnection structure is improved, long-distance low-loss transmission of radio-frequency signals is achieved, and the size is further reduced. The ultra-wideband low-noise amplifier has the advantages of miniaturization, wide instantaneous bandwidth, low noise amplification and high spurious suppression, and a solution is provided for miniaturization and low-cost mass production of an ultra-wideband radio frequency system.

The invention provides a space laser communication fine tracking assembly, which adopts a two-stage closed-loop control system to realize high-precision tracking, the first stage adopts a light spot centroid tracking technology and adjusts a light beam direction in real time through elements such as an FSM fast reflector and a CMOS camera to compensate miss distance, and the second stage adopts an optical fiber nutation coherent tracking technology to compensate miss distance. According to the system, the micro-electromechanical system (MEMS) mirror, the nutation device, photoelectric detection and the like are combined, the tracking precision is further improved through optical fiber coupling and frequency mixing processing, the FPGA programmable processor serves as a core to process images and signals and generate control signals to drive the reflector and the nutation device, accurate alignment of receiving and transmitting optical axes is ensured, and efficient and stable space laser communication is achieved. According to the invention, through combination of the first-stage light spot positioning tracking technology and the second-stage space nutation coherent tracking technology, precise control and tracking of the light spot position in space laser communication are realized, and the suppression bandwidth and precision of precise tracking are effectively improved.

The utility model discloses a multi-frequency metal detector which comprises a single-chip microcomputer master controller, a key module, a receiving module, a transmitting module, an FM module, a single-chip microcomputer programming module, an adjustable power supply module, a frequency mixing control module, a power supply module, a sound amplification module and a storage module. Wherein the transmitting module is provided with an H-bridge structure, and the H-bridge structure is connected in series with an LC to generate sine wave current potential eddy current to perform same-frequency resonance on various metals; the key module, the receiving module, the transmitting module, the FM module, the single-chip microcomputer programming module, the adjustable power supply module and the frequency mixing control module are electrically connected with the single-chip microcomputer master controller. The power supply module, the sound amplification module and the storage module are electrically connected with the frequency mixing control module. The multi-frequency metal detector provided by the utility model is stable in operation, high in efficiency, capable of generating 144 frequencies, strong in signal and high in metal detection efficiency.

The invention discloses a device and a method for testing frequency domain characteristics of a high-speed optoelectronic device. The device comprises a laser, a sawtooth wave generator, a signal source, an acousto-optic modulator, an electro-optic intensity modulator, a low-frequency photoelectric detector, a frequency spectrograph and a computer. An electro-optic intensity modulator is driven through a sawtooth wave modulation technology, and frequency-shifted and non-frequency-shifted optical carriers and frequency-shifted and non-frequency-shifted radio frequency optical sidebands are synchronously generated in an optical path in combination with radio frequency signal modulation. And after the signal is subjected to beat frequency processing by the photoelectric detector, the power of the frequency shift signal in different working states is measured by the frequency spectrograph, so that the frequency domain characteristic parameters of the photoelectric device to be measured are obtained. The method is based on sawtooth wave modulation and an amplitude comparison method, frequency domain response characteristics of a single / dual-drive electro-optic intensity modulator, dual-parallel electro-optic intensity modulation and a photoelectric detector can be accurately represented, the test method is simple, and dependence on a high-frequency test instrument is effectively reduced.

The invention discloses a parallel port type hexagonal frequency mixing solid-state transformer and a regulation and control method and device thereof, and the method comprises the steps: under the conditions that the direct-current active power and the alternating-current active power of the solid-state transformer are equal, and the instantaneous active power absorbed by each sub-bridge arm is 0, calculating the frequency of each sub-bridge arm in each sub-bridge arm; the stability relation between the fundamental frequency alternating current port current distribution coefficient and the intermediate frequency alternating current port current distribution coefficient is determined; and calculating a bridge arm circulation current through the stability relationship, thereby calculating to obtain a bridge arm circulation voltage reference value, calculating to obtain a sub-module capacitor voltage reference value of each sub-bridge arm, superposing each sub-module capacitor voltage correction component of each sub-bridge arm, obtaining a corresponding optimized sub-module capacitor voltage, and generating a corresponding modulation signal. By the adoption of the technical scheme, the multi-scene access requirement of the alternating current and direct current hybrid power distribution network is met, and inherent decoupling of three-frequency components including direct current, fundamental frequency and intermediate frequency can be achieved without an additional frequency selection network under the corresponding control method.

This invention discloses a method for quantifying the wear depth of finger sleeves used in nuclear power plant neutron flux measurement. The method includes the following steps: a. Measuring the actual dimensions of the finger sleeves in a nuclear power plant, establishing simulation models and performing simulation calculations for finger sleeves with annular and wedge-shaped defects; b. Establishing a unified calibration process, calibrating the simulation signals, and using the model to calculate signals at multiple frequencies for different finger sleeve defects; c. Performing frequency mixing calculations on the multi-frequency simulation signals to eliminate signals from the external sleeve structure; d. Drawing a graph showing the relationship between defect depth and circumferential angle and the amplitude and phase of the simulation signal, based on the specific parameters of the defect; e. Importing the measured signal values ​​into the drawn image, and quantizing the signal to defect parameters based on coordinates and legend information. This patent effectively reduces the quantization error of finger sleeve wear depth in Bobbin probe eddy current signals, improves the reliability of quantization, and can also quantify the wear angle of unilateral wedge-shaped wear.

The application discloses a six-tone signal generation circuit system, and relates to the technical field of circuit design, comprising: a quadrature frequency mixing module, a local oscillator driving module, a frequency mixing module, a signal synthesis module and a power amplification module; the quadrature frequency mixing module is used for frequency conversion of input first and second differential quadrature signals to first and sixth output signal frequencies; the signal output by the quadrature frequency mixing module, containing the first and sixth output signal frequencies, is used as the input of the signal synthesis module and the local oscillator signal of the frequency mixing module; the local oscillator driving module is used for amplifying the signal containing the first and sixth output signal frequencies as the local oscillator of the frequency mixing module; the frequency mixing module is used for frequency conversion of input differential signals to second, third, fourth and fifth output signal frequencies; the signal synthesis module is used for synthesizing the above six-tone signals; and the power amplification module is used for wideband amplification of the output six-tone signals and improvement of output power. The circuit system effectively solves the technical problem of multi-tone signal generation in a quantum conditioning circuit.

The application discloses a terahertz mixer, comprising: a radio frequency input waveguide, a local oscillator input waveguide, a local oscillator filter and an intermediate frequency output waveguide, wherein the intermediate frequency output waveguide comprises a built-in fin line transition structure and a Schottky diode pair; one end of the fin line transition structure is connected with the radio frequency input waveguide, the other end of the fin line transition structure is connected with the local oscillator filter, the Schottky diode pair is connected with one side of the fin line transition structure and connected with an intermediate frequency output port of the intermediate frequency output waveguide; after the local oscillator signal is filtered by the local oscillator filter, the local oscillator signal is transmitted to the fin line transition structure, the radio frequency signal and the local oscillator signal are loaded into the Schottky diode pair through the fin line transition structure for frequency mixing, and the intermediate frequency signal is output through the intermediate frequency output port. In this case, the fin line transition structure simultaneously carries the radio frequency signal and the local oscillator signal, which can realize spatial superposition and power efficient injection of the signals, and has good impedance matching characteristics.

The invention provides a W-band sixteen-channel chip circuit model, and relates to the technical field of radio frequency integrated microsystems. The model comprises an up-conversion frequency mixing circuit, a down-conversion frequency mixing circuit and sixteen channel circuits connected in parallel, and each channel circuit comprises two branch circuits connected in parallel. Wherein one branch is sequentially connected in series with a low-noise amplification circuit, a first six-bit numerical control phase shift circuit, a first driving amplification circuit, a five-bit numerical control attenuation circuit and a second driving amplification circuit, and the other branch is sequentially connected in series with a first power amplification circuit, a second six-bit numerical control phase shift circuit and a second power amplification circuit. The sixteen channel circuits are all connected to an input port of the radio frequency switch circuit S. The up-conversion frequency mixing circuit and the down-conversion frequency mixing circuit are respectively connected with two output ends of the radio frequency switch circuit S. According to the method, the design speed of a complex circuit or system can be increased, and a priori condition is provided for research of a large-scale complex network.

The invention belongs to the technical field of chip algorithms, and particularly relates to a circular array beam forming method and system based on a domestic FPGA. Comprising the following steps: receiving multiple paths of array element signals, and performing frequency mixing and filtering to obtain baseband I / Q data; the base band I / Q data is unpacked to be distributed and stored in a plurality of distributed memories in an FPGA (Field Programmable Gate Array) processing unit; the method comprises the following steps: reading baseband I / Q data of a plurality of channels and corresponding phase shift coefficients in parallel, and carrying out multiplication, accumulation, summation and modulo operation to generate data of a beam point; repeating the calculation step of generating the beam point data by updating the phase shift coefficient so as to generate beam domain data; reordering the calculated sequence of the beam domain data, and adjusting the output sequence of the beam domain data; the method has the advantages of being high in processing speed, high in anti-noise capacity and the like on the basis of meeting domestic substitution.

The invention provides a radio frequency transmitting and receiving fusion circuit, a transmitting and receiving front-end chip and a radio frequency heterogeneous microsystem, and the radio frequency transmitting and receiving fusion circuit comprises a first bidirectional driving amplifier which is configured to be a radio frequency power amplifier and a low noise amplifier in a radio frequency transmitting process and a radio frequency receiving process; the phase shifter is connected with the first bidirectional driving amplifier and is configured to adjust the phase of a radio frequency signal; the radio frequency signal comprises a transmitting signal and a receiving signal; and the second bidirectional driving amplifier is connected with the phase shifter and is configured to carry out frequency mixing on the radio frequency signal. The invention provides a compact and efficient transmit-receive fusion design technology, and modules and devices with similar functions in the transmitting channel and the receiving channel are deeply fused and designed, so that the size of the transmit-receive channel is reduced, the chip simulation integration level is improved, and the performance of the transmit-receive channel is improved.

The invention relates to the technical field of optical fiber communication, and discloses an optical fiber fault positioning device and method based on electric chaos and coherent detection.In the device, a narrow linewidth laser is used for generating continuous light, and a beam splitter is used for splitting the continuous light into continuous light carriers and local reference light; the electric chaotic signal generation module is used for outputting broadband chaotic electric signals; the optical modulation module is used for modulating a continuous optical carrier according to the broadband chaotic electric signal and outputting chaotic detection light; the optical coherent detection module is used for performing coherent frequency mixing on the echo signal and local reference light from the beam splitter and outputting a differential electric signal; and the signal processing module is used for performing cross-correlation operation on the broadband chaotic electric signal and the differential electric signal, and determining fault information in the optical fiber link based on a cross-correlation result. According to the invention, through fusion of electric chaos and coherent detection, a scheme with high resolution, large dynamic range, high stability and good integration potential is realized.

The application discloses a high-density multi-channel Ku-band radio frequency channel integrated micro module, and belongs to the technical field of radio frequency micro systems. The micro module adopts a three-dimensional stacking architecture, and comprises a four-channel transceiving front end IP, a transceiving frequency conversion IP, a local oscillator source IP and a high-density integrated PCB substrate, and the three IPs are silicon-based packages; a received input signal enters the four-channel transceiving front end IP, is subjected to amplitude and phase control, is transmitted to the transceiving frequency conversion IP through the high-density integrated PCB substrate, is subjected to radio frequency frequency gating filtering, is mixed and frequency-converted to an intermediate frequency output. A transmitted input signal enters the transceiving frequency conversion IP, is subjected to frequency mixing and up-conversion, is subjected to radio frequency frequency gating filtering, is transmitted to the four-channel transceiving front end IP through the high-density integrated PCB substrate, is subjected to amplitude and phase control, and is amplified and output through a power amplifier chip. The application adopts a chip preset grounding ring, a silicon substrate independent cavity and an IP shielding cavity, and solves the complex electromagnetic compatibility problem during communication.

A Costas ring utilizing pilot frequency self-adaptive sensitivity comprises a frequency mixer which carries out frequency mixing processing on an input base band to obtain an in-phase component and an orthogonal component; the phase discriminator is used for calculating the in-phase component and the quadrature component, generating a phase error and providing the phase error to the loop filter; the loop filter is used for carrying out filtering and frequency phase calculation on the phase error so as to control the phase increment of the numerical control oscillator; the numerically-controlled oscillator generates local carriers according to the phase increment and sends the local carriers to the mixer; the combiner is used for combining the in-phase component and the orthogonal component into an output base band, and the output base band is the final output of the Costas ring; the correlator is used for calculating the cross-correlation between the output baseband and the local pilot frequency, and sending the calculated cross-correlation to the power estimator; the delayer is used for providing delay of a pilot symbol length and carrying out symbol alignment before an output baseband and a local pilot are input into the power estimator; a power estimator that estimates and outputs a signal-to-noise ratio based on the cross-correlation; according to the method, the dynamic characteristic and the anti-noise capability of the Costas ring on carrier tracking are improved.

The utility model belongs to the technical field of unmanned aerial vehicle obstacle avoidance radars, and particularly discloses an anti-interference control circuit for unmanned aerial vehicle obstacle avoidance radar communication, which comprises a filtering module used for filtering signals outside a working frequency band and interference signals; the amplification module is used for amplifying the received weak signal; according to the utility model, the filtering module is used for filtering out signals and interference signals outside a working frequency band, the amplification module is used for amplifying the received weak signals, and the detection module can help to identify and separate useful signal components so as to enhance the anti-interference capability of the unmanned aerial vehicle. The frequency mixing module avoids an interference frequency band by changing the frequency of the signal, and the unmanned aerial vehicle adapts to interference signals with different intensities through the automatic gain control module, so that the signal can be correctly received and processed under strong interference, and the anti-interference capability of the unmanned aerial vehicle is effectively improved.

The invention provides a design method of an ultra-low phase noise frequency synthesizer based on regenerative frequency division. The design method comprises the following steps: step 1, enabling a source frequency to generate a multiple frequency through a frequency multiplier; step 2, inputting the multiple frequency into a two-way power divider, and generating an excessive frequency 1 through a phase-locked loop 1 by one path of output of the two-way power divider; the other path of output of the two-way power divider generates an excessive frequency 2 through a phase-locked loop 2; 3, the transition frequency 1 passes through a digital frequency divider and a regeneration frequency divider in sequence to generate transition frequency 3; and step 4, inputting the transition frequency 2 and the transition frequency 3 into a frequency mixer for frequency mixing, and then processing through a filter and an amplifier again to generate a target frequency. When the circuit topology and the transition frequency are designed, how to reduce the phase noise index is considered. According to the design method, the low-phase noise characteristic of the regenerative frequency divider is fully utilized.

The application discloses an ultra-wideband odd harmonic frequency mixer for frequency spreading, and belongs to the technical field of planar harmonic frequency mixing, and comprises a first microstrip line, a Marchand balun, a first Schottky diode, a second Schottky diode, a matching circuit and a second microstrip line; the first microstrip line is located at a radio frequency input end and is connected with a non-balanced end of the Marchand balun, two balanced ends A and B of the Marchand balun are respectively connected with an anode of the first Schottky diode and a cathode of the second Schottky diode, the cathode of the first Schottky diode and the anode of the second Schottky diode are connected in sequence and are connected with the matching circuit and the second microstrip line in sequence, and the second microstrip line is connected with a local oscillator / intermediate frequency port. The harmonic frequency mixer can be directly used for frequency expansion of an existing mainstream frequency spectrometer, and the expansion range can cover the bandwidth of two to three standard waveguide frequency bands.

The invention relates to a superheterodyne transceiver system, which belongs to the technical field of millimeter wave and wireless radio frequency links, and comprises a transmitter and a receiver, the transmitter comprises a plurality of first chopping modulation modules used for modulating a plurality of paths of baseband signals to different intermediate frequency bands through a first chopping circuit to obtain a plurality of paths of different intermediate frequency signals; the first local oscillator source is used for generating a shared up-conversion local oscillator signal; the plurality of first frequency mixing modules are used for performing frequency mixing processing on the plurality of paths of intermediate frequency signals and the up-conversion local oscillator signals respectively so as to perform up-conversion on the intermediate frequency signals to an E wave band and obtain a plurality of paths of E wave band signals; the transmitting module is used for transmitting multiple paths of E-waveband signals; and the receiver is used for receiving the multiple paths of E-band signals and demodulating a target signal from the multiple paths of E-band signals. According to the invention, the demand on a local oscillator source is reduced, so that the complexity, power consumption and cost of the system are reduced.

The invention discloses a non-contact breathing state monitoring method based on a millimeter wave radar, and belongs to the technical field of non-contact human body vital sign monitoring. The method comprises the steps that radar echo signals of a human body target are collected through a millimeter wave radar, a phase sequence is obtained through frequency mixing, filtering and phase demodulation, and breathing signals are extracted through phase unwrapping and displacement conversion; fourier transform is carried out on the respiratory signals, and the respiratory frequency and amplitude are calculated; a plurality of slope extraction algorithms are adopted, derivation is conducted on the respiration signals in the inspiration and expiration stages, and the respiration slope is obtained; and finally, integrating the respiratory rate, the amplitude and the slope, setting a threshold value and a scoring system, and quickly and accurately evaluating the respiratory distress degree. The method does not need to contact a human body, can penetrate through clothes, is suitable for various scenes such as clinical monitoring and emergency triage, and has the advantages of being easy and convenient to operate, high in real-time performance and high in reliability.