14 results about "Channel transfer function" patented technology

A fault detection system for detecting a fault condition in a direct current (DC) system. The system may include a DC power transmitter to energize a cable and a DC power receiver connected to the cable. A signal generator at the receiver employs orthogonal frequency division multiplexing (OFDM) and combines symbols for messaging or data communications with redundant symbols dedicated to fault detection. At a signal receiver, the transmitted OFDM signal is used to measure changes in the channel transfer function by monitoring changes in a parameter of the received redundant symbols. The redundant symbols need not be decoded to detect a greater-than-threshold change in the transfer function that is indicative of a fault on the cable.

A fault detection system for detecting a fault condition in a direct current (DC) system. The system may include a DC power transmitter to energize a cable and a DC power receiver connected to the cable. A signal generator at the receiver employs orthogonal frequency division multiplexing (OFDM) and combines symbols for messaging or data communications with redundant symbols dedicated to fault detection. At a signal receiver, the transmitted OFDM signal is used to measure changes in the channel transfer function by monitoring changes in a parameter of the received redundant symbols. The redundant symbols need not be decoded to detect a greater-than-threshold change in the transfer function that is indicative of a fault on the cable.

The application provides a deep neural network-based active noise reduction method, system, terminal and medium, and belongs to the active noise reduction technical field.The method comprises the following steps: collecting noise signals in real time through a reference microphone; obtaining a main channel estimation signal at a current moment; inputting the noise signal at the current moment and the main channel estimation signal after preprocessing into a trained deep neural network, obtaining a neural filter parameter through processing, generating a cancellation signal based on the neural filter parameter and the noise signal after preprocessing; and playing the cancellation signal through a loudspeaker to generate a reverse noise signal for offsetting a main channel noise signal, wherein the main channel noise signal is generated by the noise signal propagating in the main channel.The application simultaneously inputs the main channel estimation signal and the noise signal into the deep neural network for prediction, can effectively perceive the main channel transfer function, and further generates a cancellation signal highly matched with the noise information of the main channel.

The invention discloses a multi-channel active noise control method capable of reducing the calculated amount. The method comprises the following steps: (1) building a multi-channel ANC system, wherein the system comprises M (Mgt; 1) the number of the microphones; (2) measuring a secondary channel transfer function; (3) selecting Q (Qlt; m) microphones, calculating a weighting matrix by using the latest T signals collected by the microphone system, and weighting the signals of the selected Q microphones to obtain a signal of a Q channel for controlling the updating of a filter; (4) updating a control filter; and (5) calculating the output of the control filter, and inputting the output into the secondary sound source for playing. According to the method, the Q microphones are randomly selected in each period of time, and the Q microphone signals are weighted to obtain the update signal of the control filter, so that the calculation amount can be greatly reduced, and the global noise reduction effect can be obtained.

The invention discloses a direct current side frequency coupling effect suppression method and device for a grid-connected inverter. The method comprises the following steps: obtaining a forward channel transfer function according to an LCL filter parameter of the inverter; obtaining a conversion matrix according to a phase angle difference between the dq coordinate system of the power grid and the dq coordinate system of the phase-locked loop controller; obtaining an output admittance matrix according to the current loop transfer function, the forward channel transfer function and the conversion matrix of the inverter; obtaining a transfer function model according to the DC voltage loop transfer function and the output admittance matrix of the inverter; drawing a preset number of Bode diagrams according to the transfer function model by taking a first proportionality coefficient of a PI controller in the DC voltage loop transfer function as a variable; selecting a first proportionality coefficient corresponding to the Bode diagram of which the amplitude of the harmonic current meets a preset requirement as a transfer function model parameter to obtain a first model; and performing inverter control according to the first model.

A drill string communication system is described. An uphole transceiver can couple a signal onto the drill string at a power that is always greater that a selectable power for a downhole signal. Communication from a drill rig to an inground tool can be re-initiated using a maximum uphole transmit power of an uphole transceiver. A procedure can establish a new set of transmission parameters for a drill string signal to establish communication between the drill rig and the inground tool. The system can include a walkover locator that receives an active / inactive status-controlled electromagnetic locating signal. Responsive to a locating signal degradation, a reconfiguration command can modify the locating signal. The uphole transceiver and a downhole transceiver can automatically modify at least one parameter of a downhole signal. An uphole receiver can apply a compensation response to a transferred signal to compensate for a drill string channel transfer function.

The application discloses a multi-channel iteration method based on a multi-degree-of-freedom electro-hydraulic servo vibration test bench servo system decoupling method and a storage medium, and belongs to the technical field of electro-hydraulic servo control. In order to solve the problems of multi-degree-of-freedom coupling interference and insufficient waveform reproduction accuracy of a multi-channel electro-hydraulic servo vibration test bench, the application adopts an H1 non-parametric identification method to perform system identification to obtain a multi-channel transfer function matrix, and then designs a decoupling controller based on the transfer function matrix to eliminate the coupling interference between the multi-channels; finally, the control input is dynamically optimized through correction iteration, so that the purpose of improving the control accuracy of the multi-degree-of-freedom electro-hydraulic servo vibration table and accurately simulating the structural response under the action of an earthquake is achieved. The test data of the application is accurate and reliable. The application is suitable for the fields of civil engineering, traffic and machinery.

A method for performing transfer function measurements on a DUT using a dual-channel transfer function analyzer without a real-time copy of the test signal from a device such as a loudspeaker. A virtual reference test signal, serving as a copy of the DUT test signal, is played back in a channel of the transfer function analyzer at the estimated start time of the DUT test signal and at an estimated playback speed. The known playback speed of the virtual reference test signal is compared with the estimated playback speed of the DUT test signal, and any detected differences between the two signals are compensated by adjusting the playback speed of the virtual reference test signal or the playback speed of the DUT output, or both. A system for performing this method includes a virtual reference module having a detection section and an adjustment section.

A method for performing transfer function measurements on a device such as a loudspeaker (referred to as a device under test or DUT) using a two-channel transfer function analyzer without a live copy of the DUT test signal. A virtual reference test signal, which is a copy of the DUT test signal, begins playing into a channel of the transfer function analyzer at the estimated start time and estimated play-back speed of the DUT test signal. The known play-back speed of the virtual reference test signal is compared to the estimated play-back speed of the DUT test signal and any detected differences between these two signals compensated for by either adjusting the play-back speed of the virtual reference test signal or the play-back speed of the DUT output, or both. A system for performing this method includes a virtual reference module having a detection part and adjustment part.

The invention discloses a main and auxiliary dual ADC mutual calibration method and device based on a broadband current signal, and the method comprises the steps: constructing a main and auxiliary dual ADC hardware platform, and achieving the synchronous sampling time sequence control; frequency domain features of output signals of the double ADCs are extracted respectively, and a channel transmission function model is established; an optimal calibration parameter between the two channels is solved by adopting a complex frequency domain least square fitting algorithm; the fitting residual error is compensated in real time, and self-adaptive filtering is carried out; carrying out time domain fusion on the signals after dual-channel calibration, and outputting full-band signals; on-line self-diagnosis and performance monitoring are carried out by calculating an error index in real time and carrying out temperature drift compensation. According to the invention, full-band high-precision measurement can be realized, junction region jump can be eliminated, temperature self-adaptive compensation can be carried out, an on-line self-diagnosis function is realized, calculation complexity is low, expandability is realized, the method can be expanded to a multi-channel system, and the measurement requirement of a higher frequency band is supported.

The application discloses a method for separating mixed signals of a gigabit Ethernet, which comprises the following steps: selecting a first signal collection position for collecting signals at a master device end and a second signal collection position for collecting signals at a slave device end between the master device and the slave device; the master device separately sends signals to obtain a channel transfer function at the 0th signal collection; the master device and the slave device simultaneously send signals to obtain a channel transfer function at the 1st signal collection; judging whether the channel transfer functions at the 2nd signal collection are consistent; if yes, separating the sending signals of the master device and the sending signals of the slave device according to the signals collected at the two signal collection positions and the channel transfer function at the 1st signal collection; if not, re-executing until the channel transfer functions are consistent. The application utilizes the irrelevance of the signals sent by the devices at two sides of a wired network to provide a stable and effective mixed signal separation method for gigabit Ethernet devices, and further extracts the device fingerprints of the gigabit Ethernet.

The present application relates to the technical field of mine safety monitoring, and discloses a mine communication control and remote monitoring data real-time analysis system, which transmits a detection signal between communication nodes and calculates a channel transfer function to obtain a resonance fingerprint representing a physical environment of a mine; changes in the fingerprint are analyzed, and a hypothesis about a physical event is generated according to a physical model library that can be self-adaptively calibrated, and then an optimized detection signal most sensitive to the hypothesis is generated and controlled to be transmitted to verify the hypothesis; a sensor service signal transmitted through the channel is decoupled and processed using the real-time measured channel transfer function to restore original data; a relationship between the verified channel fingerprint change and a true value of the physical event is stored in a causal knowledge base, and state estimation is performed on an area where no physical sensor is deployed to realize virtual sensing and early warning. The present application realizes integration of communication and sensing, improves monitoring precision, data fidelity and early warning capability, and expands the monitoring coverage range.

The application discloses a DC side frequency coupling effect suppression method and device for a grid-connected inverter, and the method comprises the following steps: obtaining a forward channel transfer function according to LCL filter parameters of the inverter; obtaining a conversion matrix according to a phase angle difference between a power grid dq coordinate system and a phase-locked loop controller dq coordinate system; obtaining an output admittance matrix according to a current loop transfer function of the inverter, the forward channel transfer function and the conversion matrix; obtaining a transfer function model according to a DC voltage loop transfer function of the inverter and the output admittance matrix; taking a first proportional coefficient of a PI controller in the DC voltage loop transfer function as a variable, and drawing a preset number of Bode diagrams according to the transfer function model; selecting the first proportional coefficient corresponding to the Bode diagram with a harmonic current amplitude meeting a preset requirement as a parameter of the transfer function model to obtain a first model; and performing inverter control according to the first model.

The invention provides a method and a device for analyzing additional frequency control stability of a grid-following type grid-connected converter. The method comprises the following steps of: acquiring a current running state of a system for representing dynamic interaction between a voltage source type converter and a power grid; determining an active power phase coupling channel transfer function and a reactive power phase coupling channel transfer function according to the current operation state of the system in combination with the converter model; wherein the current converter model is firstly constructed based on a voltage source type current converter in the system; according to the active power phase coupling channel transfer function and the reactive power phase coupling channel transfer function, the influence of additional frequency control on damping is determined in combination with a small signal model, and an additional disturbance stability evaluation result is obtained; wherein the small signal model is firstly constructed based on a system. According to the method, the complex system is dynamically decoupled, so that the influence of the additional frequency control on the damping characteristic of the system is efficiently and accurately quantitatively evaluated.