314 results about "Intermodulation" patented technology

Aspects of the subject disclosure may include, for example, causing radio frequency (RF) signals to be transmitted via an antenna system in a plurality of directions, and responsive to transmission of the RF signals, monitoring signals that are received by the antenna system to detect an interference signal that originates from a passive intermodulation (PIM) source. Other embodiments are disclosed.

Aspects of the subject disclosure may include, for example, detecting an interference signal in two or more signals received via orthogonally-polarized elements of an antenna system, the interference signal originating from a passive intermodulation (PIM) source, measuring a polarization of the interference signal, by comparing the two or more signals, to estimate a shape of the PIM source, and generating information regarding the shape to facilitate locating of the PIM source. Other embodiments are disclosed.

Aspects of the subject disclosure may include, for example, causing radio frequency (RF) signals to be transmitted via an antenna system in a plurality of directions, and responsive to transmission of the RF signals, monitoring signals that are received by the antenna system to detect an interference signal that originates from a passive intermodulation (PIM) source. Other embodiments are disclosed.

The invention relates to the technical field of electronic component testing for investigating or analyzing internal microstructures and physical properties of materials by utilizing an electrical means, and discloses an online testing and analyzing method for physical properties of electronic component materials, which comprises the following steps of: constructing a composite excitation signal formed by linearly superposing a main carrier voltage and a perturbation wave voltage; applying the signal to a to-be-tested electronic component and acquiring response current; and extracting an intermodulation current amplitude at an intermodulation frequency point in the frequency spectrum of which the linear response interval is excluded, calculating a nonlinear response coefficient of the material in combination with the excitation amplitude, and comparing the nonlinear response coefficient with a preset degradation threshold so as to judge whether the nonlinear response coefficient is qualified or not. By extracting intermodulation components which cannot be generated by linear contact resistance, physical isolation of external contact noise in a frequency domain is realized, and the problem that contact resistance fluctuation and material intrinsic aging cannot be distinguished in a traditional linear impedance test is solved.

The invention relates to the technical field of power battery health state evaluation and anomaly recognition, in particular to a remote health state analysis and anomaly recognition method for an electric bicycle battery, which comprises the following steps of: under an access working condition, applying small-signal active excitation and synchronously acquiring to form an opportunity diagnosis excitation data window; time-frequency coupling modeling including equivalent impedance modeling, harmonic wave and intermodulation fingerprint modeling, Koopman operator modeling and entropy coefficient difference is carried out, and a spectral measurement geometric distance is constructed through optimal transmission to generate a multi-domain response packet, a physical invariant vector and an uncertainty matrix; according to the geometric distance and consistency score gating and hierarchical standardization, obtaining a health state estimation record and an abnormal event set by adopting a shape-limited health mapping model; and in combination with mapping Jacobian and dual potential, generating an opportunity diagnosis incentive plan of a next period by adopting D-optimal test design, and updating a group health manifold, thereby realizing cross-environment, cross-equipment and traceable remote health assessment and early anomaly recognition.

The invention relates to the technical field of on-line monitoring, in particular to an insulation fault on-line monitoring method and system for a medical IT system control cabinet. The method comprises the following steps: selecting a non-integer frequency multiplication detection frequency according to equivalent ground distributed capacitance in a previous monitoring period, and superposing the non-integer frequency multiplication detection frequency with a fundamental frequency to form a composite signal injection system; collecting signals to calculate a voltage instantaneous harmonic distortion rate change gradient, and selecting a time window to split the leakage current according to the change gradient; on the basis of dispersion estimation signal-to-noise ratio weighted fusion current vectors, insulation resistance and distributed capacitance are calculated; constructing a four-dimensional original feature vector composed of the insulation parameter, the phase difference and the intermodulation component energy; constructing a diagonal weighting matrix based on the resistance-capacitance ratio and the gradient to transform a feature vector, and determining the fault attribution through the Mahalanobis distance calculation with the fault template library. According to the scheme, harmonic interference can be avoided, calculation stability can be improved, insulation instantaneous sudden change can be quickly responded, and different fault types can be accurately distinguished to guide maintenance.

The invention relates to the technical field of microelectronics, semiconductors and communication, and discloses a radio frequency switch chip, and the circuit structure of the radio frequency switch chip comprises a transformer type differential inductor T-L1, a transformer type differential inductor T-L2, a capacitor C1, an NMOS transistor M1, an NMOS transistor M2, a gate resistor RG1, and a gate resistor RG2. The radio frequency switch chip provided by the invention adopts a differential structure, so that the parasitic inductance effect of a grounding key and a wire during packaging and testing can be eliminated, and the insertion loss and the isolation performance are improved; compared with a single-end port, the lower impedance of the differential port is more beneficial to improving the power capacity of the switch; the differential structure allows the transformer type differential inductor to use differential signal characteristics, the equivalent quality factor of the inductor is improved, and the circuit performance is improved; the differential structure can improve the linearity of the circuit, especially the second-order intermodulation effect; the differential structure can be compatible with a modern silicon-based CMOS radio frequency system, and an additional balun is not needed for signal conversion.

An electronic device may include wireless circuitry. The wireless circuitry can include a first input transistor, a first capacitance neutralization having a source terminal coupled to a tail node, and a second order intermodulation generation circuit configured to produce second order intermodulation signals at the tail node. The wireless circuitry can further include a second input transistor and a second capacitance neutralization transistor having a source terminal coupled to the tail node. The first and second capacitance neutralization transistors can be cross-coupled with the input transistors. A fixed or adjustable current source can be coupled to the tail node. The second order intermodulation generation circuit can include a transistor biased in a weak inversion mode.

The invention discloses a method for automatically setting a working frequency based on a field radio frequency environment, which relates to the technical field of wireless communication, and comprises the following specific steps of: acquiring field radio frequency environment data in real time through a wireless frequency data acquisition module, and storing the field radio frequency environment data in a database; the data processing module screens non-interference frequency points based on third-order intermodulation interference compatibility calculation, the working frequency of the receiver and the working frequency of the transmitter are dynamically adjusted through the equipment control module, and the database, the data processing module and the equipment control module cooperate to achieve automatic frequency switching. A receiver in the method is provided with a standby receiving sub-module, when it is detected that a current frequency point is interfered, the current frequency point is automatically switched to a standby frequency point, stable operation of a system is ensured, the transmitter synchronizes the frequency with the receiver through a communication protocol in a speaking state, signal transmission is stopped in a mute state, environment interference can be monitored in real time, manual intervention is not needed, and the method is suitable for popularization and application. Manual frequent manual operation for frequency adjustment is avoided, and the anti-interference capability of a wireless communication system is remarkably improved.

Systems and methods of passive intermodulation (PIM) detection in a radio frequency (RF) system including: injecting, from each port of a two-port PIM analyzer, two test tones or a wideband modulated carrier signal into the system one port at a time; receiving, at each port, a response signal from the system in response to the test tones or wideband modulated carrier signal; injecting, from two ports of the two-port PIM analyzer, test tones or a wideband modulated carrier signal into the system; receiving, at the two ports, a response signal from the system in response to the test tones or wideband modulated carrier signal; and identifying one or more PIM sources based on the response signals.

The invention discloses a broadband high-precision voltage compensation control method of a power amplifier, relates to the technical field of broadband compensation, and is used for solving the problem of low voltage compensation efficiency caused by cooperative distortion caused by mutual regulation and control when the signal frequencies of different input channels are close. Recording information of the input signal is called to judge the signal type of the input signal, when the multi-frequency signal exists in the analysis database, the signal amplitude and the signal frequency of the multi-frequency signal are collected, the high-order intermodulation distortion degree of the input signal is judged, and the distortion index of the multi-frequency signal is calculated; selecting to start intermodulation distortion processing or enter a frequency coexistence risk test mechanism according to the high-order intermodulation distortion degree of the multi-frequency signals, calculating frequency intermodulation characteristics of different single-frequency signals, and performing effect integration on the frequency intermodulation characteristics of all the single-frequency signals in the analysis database according to the number of the single-frequency signals; and judging whether to carry out intermodulation distortion processing or not by combining the distortion index of the multi-frequency signal.

The present invention relates to an audio-video signal processing apparatus, which comprises: an audio-video application circuit, a power supply circuit, and at least one impedance matching circuit, wherein the audio-video application circuit is configured to receive, process, and output audio and / or video intermodulation signals; the power supply circuit is configured to output a DC voltage to the audio-video application circuit for powering it; the impedance matching circuit includes a plurality of impedance elements, at least one input end, and at least one output end, and is arranged before or inside the audio-video application circuit. The audio-video signal processing apparatus of the present invention can perform impedance matching and timing adjustment on the power supply signal and the audio and / or video intermodulation signals, thereby reducing the intermodulation distortion generated by the audio and / or video intermodulation signals during transmission through the impedance matching circuit.

The invention discloses a time interference double-target electrical stimulation system, which comprises a signal generation unit used for generating multiple paths of carrier signals and adjusting the frequency, amplitude and / or phase of the carrier signals; the current output unit is used for converting the multiple paths of carrier signals into multiple paths of carrier currents, and electrical isolation and intermodulation suppression are provided between the multiple paths of carrier currents; the electrode unit is electrically connected with the current output unit and comprises a plurality of electrodes and a position subunit, the plurality of electrodes are used for receiving the multi-channel carrier current so as to discharge in an attached target area, and the position subunit is used for determining the attaching position of each electrode; and the control unit is used for controlling the discharge of the plurality of electrodes, detecting the impedance and carrier current at the plurality of electrodes to assist the position subunit in determining the fitting position and detecting the frequency and / or phase of the plurality of carrier current to control the signal generation unit to adjust the frequency and / or phase of each path of carrier signal. The system realizes independent stimulation of two target spots in a hardware-level time interference mode, has signal output with high stability and low mutual interference, and can perform real-time feedback regulation and safety protection.

A wireless communication system includes a transmitter, a plurality of passive substantially linear medium portions including one or more first portions and a second portion, one or more passive substantially nonlinear medium portions disposed proximate the substantially linear medium portions, and for each first portion, a dielectrically lossy or magnetically lossy first material disposed on the first portion. When the transmitter transmits first and second radio waves, the substantially linear and nonlinear medium portions receive the first and second radio waves and generate first and second signals propagating therein, where at least one intermodulation signal is generated in the one or more substantially nonlinear medium portions from the first and second signals, and the one or more first materials reduces the generation of the at least one intermodulation signal by at least 2 dB.

The invention discloses a method for acquiring passive intermodulation interference caused by oxidation corrosion of a base station antenna, and aims to further supplement and improve the existing research so as to quantitatively evaluate the passive intermodulation interference generated after the oxidation corrosion of the base station antenna. An analysis object is set as the side surface of a microstrip line conductor, firstly, the amplitude coefficient AD2 of voltage of each point in the lower edge area of the side surface of an unoxidized and corroded microstrip line under the action of a single carrier signal is determined, and then after it is determined that the microstrip line is oxidized and corroded, the amplitude coefficient AD2 of voltage of each point is determined. According to the method, the tunneling current density JMIM and the total tunneling current IMIM of the oxidation corrosion areas are obtained according to the average voltage value of the oxidation corrosion areas, and on the basis, the third-order passive intermodulation voltage V3rd-PIM (t) is calculated, so that the passive intermodulation interference generated after oxidation corrosion of the base station antenna is quantitatively evaluated.

An electronic device may include wireless circuitry with a processor, a transceiver circuit, a front-end module, and an antenna. The front-end module may include amplifier circuitry such as a low noise amplifier for amplifying received radio-frequency signals. The amplifier circuitry may include non-linearity suppression circuitry that suppresses or reduces non-linear behavior of components such as a core amplification transistor and a degeneration inductor within the amplifier circuitry. The non-linearity suppression circuitry may include an intermodulation distortion suppression circuit having an auxiliary amplification transistor. The non-linearity suppression circuitry may include a frequency-selective filter coupled to the degeneration inductor.

The invention discloses an RRU multi-band passive intermodulation elimination method based on a sequence-to-sequence learning model, and the method comprises the steps: obtaining a transmitting signal and a receiving signal of a multi-band RRU, carrying out the feature extraction of the signals through adaptive transformation, and obtaining the multi-band intermodulation interference feature data; generating a nonlinear intermodulation feature vector based on the multi-band intermodulation interference feature data; training a PIM signal prediction model by using a sequence-to-sequence learning model, and performing residual compensation on a prediction result based on an error optimization mechanism; performing adaptive filtering processing on the predicted PIM interference signal to generate an optimized interference compensation signal; and dynamically updating the PIM signal prediction model by using an online learning mechanism based on the signal data after interference suppression. According to the method, the multi-band nonlinear intermodulation characteristics can be modeled in a self-adaptive manner, the PIM prediction precision is improved, and the calculation complexity is reduced.

The invention relates to the technical field of radio frequency cable testing, in particular to a method and device for improving cable intermodulation testing, and the method comprises the steps: pretreating a cable sample, cleaning a cable connector joint, and sleeving a welding part of a cable and a connector with a flexible protective sleeve; the test fixture is adapted, and the rotating shaft distance and the contact pressure of the dynamic test fixture are adjusted; carrying out multi-parameter collaborative testing, starting an intermodulation analyzer to load a test carrier, and collecting various data in real time; dynamic stress loading is carried out, a stepped vibration stress loading mode is adopted, and intermodulation value changes are monitored in real time; data storage and analysis: storing the data in the test process into a database to generate a test report; the device comprises a customized cleaning module, a test fixture module, a multi-parameter monitoring module, a welding part protection module and a control and data analysis module. The problem that an existing static test is separated from an actual working condition is solved, small-size cable test damage is avoided, and errors caused by manual operation are reduced.

The invention discloses a system for simultaneously suppressing second-order nonlinearity and third-order nonlinearity in a direct modulation laser (DML), which belongs to the field of optical communication, and can simultaneously suppress the second-order nonlinearity and the third-order nonlinearity in the system under the condition of DSP-FREE through the combined action of a broadband pre-distortion circuit and an optical path push-pull structure. Wherein at a transmitting end, a set of Schottky diodes and Chebyshev gradient transmission lines which are connected in parallel reversely are adopted to build a DC-10GHz broadband pre-distortion module, and a radio frequency signal generates a reverse third-order intermodulation (IMD3) component through an analog pre-distortion circuit so as to counteract forward third-order nonlinearity of a laser; at a receiving end, a second-order intermodulation (IMD2) component is differentially eliminated through an optical path push-pull modulation architecture. Compared with a traditional DSP scheme, digital signal processing is not needed, the method has the advantages of being low in complexity and wide in bandwidth, and nonlinear accurate compensation of an optical communication system can be achieved.

The invention provides a base station OTA intermodulation test method based on a reverberation chamber. The reverberation chamber comprises a shielding shell which encloses a closed cavity, and a stirrer which is arranged in the closed cavity and is used for stirring electromagnetic waves transmitted in the closed cavity; and the tested base station and the interference signal antenna are arranged in the working area of the closed cavity in parallel at a preset interval. The method comprises the following steps: starting a tested base station, and enabling the tested base station to transmit a main signal of a first frequency and bandwidth in a preset transmitting power mode; providing an interference signal of a second frequency and bandwidth with a predetermined power level to an interference signal antenna to generate intermodulation interference on the tested base station so as to perform an intermodulation interference test; under the condition that the stirrer is started for electromagnetic wave stirring, electromagnetic wave signals in the closed cavity are collected; and analyzing and processing the acquired electromagnetic wave signal to obtain a measurement result of the intermodulation interference test index based on the total radiation power. The universality of the emission intermodulation test is realized, and the test cost and time are reduced.

A method for reducing receive band leakage may include: sensing, at a full duplexer, passive intermodulation distortion and power amplifier distortion; generating, at a processing device, a passive intermodulation distortion and power amplifier distortion cancellation signal; and cancelling, on a receive path, the passive intermodulation distortion and power amplifier distortion using the passive intermodulation distortion and power amplifier distortion cancellation signal.

The invention discloses an up-mixing harmonic energy communication system and method based on direct-mixing intermodulation signal suppression. The communication system includes a receive antenna and an integrated rectified transmitter. The integrated rectified transmitter includes a first branch and a second branch. The invention provides an integrated rectification transmitter with a double-branch structure, an IM2 modulation module is arranged at the tail end of a first branch, and a 90-degree phase shift network is arranged at the head end of a second branch, so that uncontrollable IMD3 signals generated in the first branch and the second branch have a phase difference of 180 degrees and are mutually counteracted; in this way, only the upmixing IMU3 signal which can be controllably and accurately modulated in the first branch is reserved in the uploaded backscattering signal, and more accurate and reliable wireless energy cooperative information transmission is achieved. According to the invention, the frequency of the IM3 signal for communication is close to that of the input dual-tone signal, so that multiplexing can be realized by only needing a small bandwidth in the design of the receiving and transmitting antenna.

Aspects of the subject disclosure may include, for example, detecting, by a monitoring system associated with a communication system, signals received at an array of orthogonally-polarized radiating elements of an antenna, causing, via a motorized drive assembly, the array of orthogonally-polarized radiating elements to sequentially rotate to a plurality of positions, obtaining, by a control system from the monitoring system and for each of the plurality of positions, data relating to signals from the array of orthogonally-polarized radiating elements, based on the data, determining, by the control system, an optimal position of the plurality of positions for the array of orthogonally-polarized radiating elements at which an impact of passive intermodulation (PIM) on the communications system is minimized, and controlling, by the control system, the motorized drive assembly to cause the array of orthogonally-polarized radiating elements to occupy the optimal position. Other embodiments are disclosed.

A system and method for measuring and analyzing power flow parameters in RF-based excitation systems for semi-conductor plasma generators. A measuring probe is connected to an RF transmission line for receiving and measuring voltage and current signals from the transmission line. A high-speed sampling process converts the measured RF voltage and current signals into digital signals. The digital signals are then processed so as to reveal fundamental, intermodulation, triple beat, and harmonic amplitude and phase information corresponding to the original RF signals. The measurement system may also inhibit arcing by detecting when the amplitude of the intermodulation or triple beat signal exceeds a predetermined threshold, and indicating an alarm and / or reducing the power of the plasma generator when the predetermined threshold is exceeded.

The invention discloses an optimal linear point searching method for a silicon-based Mach-Zehnder modulator. According to the method, the linearity of a corresponding working point is estimated according to the power of a fundamental component and a third-order intermodulation component of an output signal of the modulator, and the optimal linear point of the modulator can be obtained based on the maximum estimated value of the linearity. According to the method, a maximum entropy spectral subtraction method is adopted to reduce a signal noise floor, and a violent search method is adopted to retrieve an optimal combination of a modulator upper and lower arm phase difference and a reverse bias voltage to obtain an optimal working point. Compared with a conventional linearity test method that the linearity is obtained by testing when the working point of the modulator is set to be an orthogonal point, the optimal linear point searched by the method can obviously improve the linearity of the modulator, and a high-linearity silicon-based integrated microwave photon system can be realized.

Embodiments herein describe a circuit including a passive intermodulation (PIM) model circuit configured to process first data to generate a PIM interference model output to be concatenated with second data, the second data including a first carrier frequency and a second carrier frequency, and the circuit further including a PIM model adapt circuit configured to receive frequency shifted captured data and frequency shifted PIM models to generate updated values to compensate for PIM interference after the PIM interference model output is concatenated with the second data.

The invention relates to a multi-frequency sensitivity test evaluation method and system, the evaluation method is realized based on a multi-frequency sensitivity test device, and the device comprises a signal generator, an attenuator, a power amplifier, a directional coupler, a power meter, a frequency spectrograph and an interference applying module. According to the evaluation method, the sensitivity of the electronic product to single-frequency interference and multi-frequency interference in different frequency bands can be determined, modes such as frequency band sub-band division and reverse frequency spectrum monitoring are designed, the influence of multi-frequency-point signal intermodulation interference on a test result can be reduced, and the test accuracy is improved. The problem that the accuracy of a multi-frequency-point sensitivity test result is affected due to the fact that a traditional multi-frequency-point test method generates extra interference risks on the tested electronic product is solved. Meanwhile, under the condition that the multi-frequency sensitivity indication parameter provided by the invention meets a certain condition, a continuous wave sensitivity test method can be adopted to replace a multi-frequency point sensitivity test method, so that the test cost is reduced.

The invention discloses a train running gear bearing state prediction and early warning method and system, and the method comprises the steps: synchronously collecting vibration, noise and temperature data, and building a standard vibration reference based on rotation period segmentation; extracting a component characteristic frequency and confirming fault information by adopting a frequency spectrum decomposition and intermodulation analysis technology, and determining a monitoring working frequency and a component weight table; a temperature confrontation processing mechanism is introduced, decoupling parameters are generated through a heat distribution matrix and directional heat flow analysis, and accurate separation of temperature influence and mechanical wear signals is achieved; constructing an equivalent transformation matrix based on a noise dependency relationship, and performing standardized transformation on pure vibration data to generate a comparable state index; through abrasion tracking and vibration transmission analysis, path reconstruction is carried out in combination with transfer parameters, and accurate positioning and evolution prediction of faults are achieved; and finally, dynamically adjusting the component weight based on the path control signal, establishing a four-level grading early warning system, and realizing real-time monitoring and intelligent early warning of the running state of the bearing.

The invention discloses a low-frequency intermodulation leaky coaxial cable based on an asymmetric slot design, and relates to the field of cables, the low-frequency intermodulation leaky coaxial cable comprises a cable body, a seven-core stranded silver-coated copper wire is installed in an inner cavity of the cable body, a gradient insulating layer is installed on the outer wall of the cable body, a composite outer conductor is installed on the outer wall of the gradient insulating layer, and the composite outer conductor is connected with a cable core. And a multi-layer sheath is arranged on the outer wall of the composite outer conductor. According to the low-frequency intermodulation leaky coaxial cable based on the asymmetric slotted hole design, the periodic structure characteristic of a traditional leaky coaxial cable is thoroughly broken through through the full-penetrating four-dimensional gradual change slotted holes and the semi-penetrating four-dimensional gradual change slotted holes which are asymmetrically arranged; the width, the depth and the arrangement density of the full-penetrating four-dimensional gradually-changing slot holes and the semi-penetrating four-dimensional gradually-changing slot holes are gradually changed, so that electromagnetic waves cannot form standing waves and resonance at a specific frequency, a generation path of an intermodulation product is fundamentally cut off, excessive concentration of energy in a local area can be avoided, and the nonlinear effect is remarkably reduced.

The invention relates to a model training method and device and a signal conversion method. The model training method comprises the following steps: inputting an original digital signal sent by a digital signal source into an initial model to obtain a sample digital signal output by the initial model; performing digital-to-analog conversion on the sample digital signal through a digital-to-analog conversion circuit in the signal processing chip to obtain a sample analog signal corresponding to the sample digital signal; determining a predicted value of a nonlinear distortion index of the digital-to-analog conversion circuit according to the sample digital signal and the sample analog signal; wherein the nonlinear distortion index comprises a total harmonic distortion index and / or an intermodulation distortion index; and performing parameter adjustment on the initial model according to the predicted value and the expected value of the nonlinear distortion index to obtain a digital signal conversion model. The digital signal conversion model obtained through training of the method can process original digital signals so as to compensate nonlinear distortion of a digital-to-analog conversion circuit.