308 results about "Signal synthesis" patented technology

A low voltage ride through control method for a grid-forming inverter based on dynamic internal potential adjustment comprises the following steps: detecting a voltage per unit value of a grid-connected point in real time, and comparing the voltage per unit value with a threshold value to judge a voltage drop event and trigger low voltage ride through control; dynamically calculating active and reactive power reference values through a reactive compensation equation and an active current limiting equation according to the voltage amplitude and the power reference value before falling during the ride-through period; inputting the active reference value into a virtual rotor motion equation to generate a reference phase, and outputting a phase reference signal in combination with a dual-mode phase compensation controller; superposing the reactive reference value with the reference voltage through a reactive voltage regulating ring to generate a voltage amplitude reference signal; synthesizing an internal potential according to the phase and the amplitude reference signal, and obtaining an inductive current reference value through virtual impedance control and current amplitude limiting; and finally, a driving signal is generated through the current inner loop controller and the modulation module. According to the invention, overcurrent can be effectively inhibited, rapid reactive power support is provided, and synchronous stability and smooth transition in a fault period and a recovery process are ensured.

The invention discloses a frequency domain ground penetrating radar transmitting source coding and receiving signal synthesis method and system. The method comprises the following steps: constructing a frequency domain coding continuous wave ground penetrating radar transmitting signal by extracting amplitude and phase information of multiple frequency points of a time domain ultra-wideband transmitting pulse; adopting a fast forward modeling method based on impulse response to realize forward modeling of a coding source emission signal of the typical geoelectric model; in-phase components and orthogonal components of all frequency points are extracted, frequency responses are synthesized into responses of quasi-time-domain transmitted pulses through an inverse Fourier transform method, the high resolution equal to that of time-domain ultra-wideband transmitted signals is obtained, and higher anti-noise performance is achieved. According to the invention, the amplitude phase coding continuous wave transmitting signal is adopted, so that the frequency spectrum shaping of the quasi-time domain pulse of the transmitting frequency spectrum is realized, the resolving power of the synthetic signal is improved, and a theoretical basis is laid for signal synthesis of frequency domain ground penetrating radar hardware design.

The invention discloses a dynamic electromagnetic shielding method for a complex electromagnetic environment and a shielding device thereof, and the method comprises the steps: obtaining real-time voltage data in the complex electromagnetic environment, carrying out the voltage feature analysis, outputting a feature vector of a real-time voltage signal, and analyzing the type of an interference source of a current electric field according to the feature vector, performing interference trend time sequence prediction processing on the feature vector through a pre-trained LSTM model according to the interference source type to obtain a time domain voltage value and a phase deviation value, and performing composite loss coefficient calculation on the time domain voltage value and the phase deviation value to obtain a composite loss coefficient; and performing reverse offset signal synthesis processing on the voltage interference signal according to the calculated composite loss coefficient, performing coil dynamic activation processing on a preset multi-coil array according to the synthesized reverse offset signal, generating a directional offset magnetic field corresponding to the real-time electromagnetic interference, and performing electromagnetic offset shielding on the current electromagnetic interference. According to the invention, transient interference can be responded in time, and the electromagnetic shielding effectiveness can be improved.

The invention discloses a photovoltaic optimization regulation and control method and device based on an MPPT technology, and particularly relates to the technical field of photovoltaic power generation control, and the method specifically comprises the following steps: S1, full-link operation state synchronous collection, S2, DC bus ripple feature extraction, S3, multi-source disturbance quantitative evaluation, S4, cooperative control parameter decision making, and S5, grid-connected signal synthesis modulation. A multi-source disturbance quantitative evaluation system is adopted, the irradiance change gradient, the frequency ratio and the switching noise contribution ratio are subjected to multi-dimensional fusion, a dynamic weight distribution mechanism is established, and parallel optimization of MPPT mode selection, disturbance step length adjustment and PWM phase shift angle is achieved through a cooperative control parameter decision architecture. A response delay bottleneck existing in a traditional serial decision mode is broken through, and a ripple compensation component is dynamically injected while stable output of fundamental current is maintained based on a grid-connected signal modulation strategy of vector synthesis.

The invention discloses an intermediate frequency electro-therapeutic apparatus, which comprises a controller and a waveform synthesis circuit, and is characterized in that the waveform synthesis circuit comprises a first amplitude adjusting circuit, a second amplitude adjusting circuit and a synthesis adjusting circuit, and the controller generates a first PWM signal according to the overall amplitude information; the first amplitude adjusting circuit performs amplitude modulation processing on an input original waveform according to the first PWM signal to generate a first analog waveform signal; the controller obtains amplitude information corresponding to the frequency of the modulation waveform by using the phase accumulator, and generates a second PWM signal; a second amplitude adjusting circuit performs multiplication operation on the second PWM signal and the first analog waveform signal to obtain a second analog waveform signal and obtain an inverted waveform signal; the controller obtains amplitude information corresponding to the frequency of the fundamental frequency waveform by using a phase accumulator, and generates a third PWM signal; and the synthesis adjusting circuit performs multiplication operation on the third PWM signal and the second analog waveform signal or the inverted waveform signal to generate an intermediate frequency treatment waveform.

The invention relates to the technical field of LED illumination control, and discloses a lamp strip brightness control system and method capable of realizing self-adaptive adjustment, and an LED lamp strip. An environment data acquisition module of the system acquires environment illumination intensity data and environment color temperature data in real time to form a multidimensional environment parameter matrix containing a timestamp; a dynamic feature extraction module performs multi-scale decomposition on the matrix, extracts illumination intensity change trend features and color temperature fluctuation features, and constructs dynamic feature vectors; the adaptive decision module calculates a brightness adjustment weight based on the dynamic feature vector, and generates a brightness adjustment instruction in combination with a preset brightness constraint condition; the signal synthesis module converts the brightness adjustment instruction into a pulse width modulation signal, and superposes a high-frequency noise suppression signal to optimize the signal stability; and the driving execution module adjusts the driving current of the LED lamp strip according to the pulse width modulation signal so as to realize self-adaptive brightness adjustment. The system can improve the stability and adaptability of brightness adjustment and improve the visual experience of a user.

The invention discloses a vehicle-mounted CAN bus anti-interference communication system and method based on photocoupling, and the system comprises an anti-interference communication system frame, the anti-interference communication system frame comprises a CAN bus receiving and transmitting module, a photocoupling isolation module, and a signal processing and separating module, the CAN bus receiving and transmitting module is used for receiving and transmitting CAN bus signals, and the photocoupling isolation module is used for receiving and transmitting the CAN bus signals. The photoelectric coupling isolation module is used for realizing transparent conversion of data between an optical signal and an electric signal and realizing electrical isolation of a physical layer while maintaining the integrity of a CAN protocol, and the signal processing and separation module is used for constructing a cooperative processing mechanism of time sequence calibration, differential judgment, logic reconstruction and signal synthesis. According to the invention, based on a physical layer signal isolation mechanism of optoelectronic isolation, a bidirectional independent transmission path of a CAN bus TXD / RXD channel data stream is established, and TXD mapping data and CAN bus effective data in an RXD channel are accurately separated, so that the system reliability in an industrial-grade communication scene can be obviously improved.

The invention discloses an active disturbance rejection controller control method and device, and the method comprises the steps: receiving an actual output feedback signal of a controlled object and a historical output control signal of a controller based on a linear expansion state observer, calculating the total disturbance of a system in real time through a three-order state-space equation, and obtaining a disturbance estimation value; receiving the disturbance estimation value and the control input gain coefficient based on a compensator, calculating a dynamic compensation amount for offsetting the total disturbance of the system, and outputting the dynamic compensation amount to a signal synthesis node; a deviation signal of a set value signal used for defining the target state of a controlled object and a feedback signal actually output by the controlled object is received based on a controller, and an anti-interference basic control signal is generated in combination with the bandwidth of the controller; and subtracting the dynamic compensation amount from the anti-interference basic control signal based on the signal synthesis node to generate an active-disturbance-rejection control amount, outputting the active-disturbance-rejection control amount to a controlled object, and suppressing external interference and internal parameter drift of the controlled object.

The invention relates to the technical field of neuroacoustics, in particular to a personalized brain wave induced audio generation method and system, and the method comprises the steps: S1, extracting multi-dimensional features of an input audio signal, the extracted dimensions at least comprising a time domain feature, a frequency domain feature, a pitch feature, an emotion feature and a complex feature; s2, on the basis of the multi-dimensional features extracted in the step S1, parameters of four neuroacoustic induction mechanisms are calculated in parallel; and S3, according to the features obtained in the step S1 and the quadruple mechanism parameters obtained in the step S2, signals corresponding to the four mechanisms are fused through a weight distribution strategy and a signal synthesis formula to generate a final brain wave induction audio. The method has the advantages that four mechanisms of rhythm synchronization, harmonic resonance, neural oscillation coupling and binaural beat frequency effect are fused, parameters of all the mechanisms are dynamically adjusted by analyzing music characteristics, and efficient personalized brain wave induction is achieved.

The invention discloses a system and a method for realizing positive and negative weighting in an optical domain, and the system comprises a multi-wavelength light source array which provides multi-channel optical signals, and each wavelength corresponds to an input channel; the adjustable bias photoelectric modulator arrays are in one-to-one correspondence with the light sources, a quiescent working point is biased in a positive / negative slope linear region of a transmission curve through an independent bias circuit, positive and negative weight symbol control is realized, and an input electric signal is loaded; the multi-wavelength micro-ring weighting unit is used for weighting the modulated optical signal by regulating and controlling the transmissivity of the micro-ring; the photoelectric detection unit adopts a single-path detector to receive a composite optical signal and convert the composite optical signal into an electric signal; and the capacitor blocking and signal synthesis unit filters a direct current component, synthesizes an alternating current weighted signal and outputs a real number weighted sum. The system does not need to balance detectors and redundant devices, simplifies hardware architecture, reduces cost and size, reduces power consumption, improves weighting precision and reliability, supports flexible expansion of multi-wavelength channels, adapts to requirements of a large-scale optical neural network, and provides support for optical calculation integration and low-power-consumption landing.

The invention relates to a square wave generation method and system based on a DDS signal transmitter, and belongs to the technical field of digital electronic signal synthesis. The method comprises the following steps: calculating a digital analog signal sampling frequency based on a square wave output frequency set by a user, and obtaining a digital fundamental frequency phase signal according to a phase-locked loop precision range; mapping the digital fundamental frequency phase signal into a sinusoidal amplitude signal according to a digital phase accumulation mechanism to obtain a digital-analog conversion clock, binarizing the sinusoidal amplitude signal, and outputting a square wave output period; dividing a square wave output period into a low level region and a high level region according to the precision range of the phase-locked loop, reading a square wave output frequency set by a user through a random storage address, and outputting a non-offset phase-locked square wave; and constructing an error accumulation self-checking architecture to calculate a frequency control word, and when detecting that the frequency control word has a decimal discarding error, recalculating the frequency control word.

The invention relates to a low-power-consumption clock delay method and system in the technical field of integrated circuits, and the method comprises the following steps: carrying out the phase alignment of a counting clock signal and a to-be-delayed clock signal based on the counting clock signal, and generating a first phase clock alignment signal and a second phase clock alignment signal; extracting rising edge information and falling edge information of the first phase clock alignment signal to obtain a pulse signal; splitting the clock rising edge information and the clock falling edge information to obtain a first pulse filtering signal and a second pulse filtering signal; performing coarse delay on the first pulse filtering signal and the second pulse filtering signal in sequence, and performing signal synthesis processing after coarse delay to obtain a coarse delay clock signal; and performing fine delay on the coarse delay clock signal based on the digital time converter to obtain a fine delay clock signal, thereby solving the problem that the existing delay technology cannot simultaneously realize high delay precision and large dynamic range under the condition of low power consumption.

The invention provides a permanent magnet synchronous motor rotating speed control method and system, and belongs to the technical field of motor control. The method comprises the following steps: firstly, constructing a discrete time mathematical model of a motor and an external source system comprising a lumped reference signal and lumped interference, and establishing a composite system model according to the discrete time mathematical model; then, constructing a dimensionality reduction observer to estimate an external source signal, and performing state and input transformation in combination with a regulator equation; thirdly, constructing a constraint set of the transformation system, and decomposing a state variable into a nominal component, a deterministic error component and an uncertain error component; a time-varying constraint tightening set is dynamically constructed according to the error, a model prediction control optimization problem with dynamic tightening constraint is solved online, and a nominal control quantity is obtained; and finally, combining the nominal control quantity and the estimated external source signal to synthesize an actual control voltage. According to the method, interference can be effectively suppressed, system security constraints are strictly ensured, recursion feasibility and closed-loop stability of control are ensured, and the dynamic response speed is increased.

The embodiment of the invention provides a frequency multiplication amplification circuit applied to a phase-locked loop and communication equipment, and the frequency multiplication amplification circuit applied to the phase-locked loop comprises a local oscillator frequency division module which is electrically connected with the output end of the phase-locked loop and is used for receiving a radio frequency signal output by the phase-locked loop and outputting a local oscillator signal according to the radio frequency signal; the frequency mixing module is electrically connected with the output end of the phase-locked loop and the output end of the local oscillator frequency division module, and is used for synthesizing a frequency mixing signal according to the radio frequency signal and the local oscillator signal; wherein the frequency of the frequency mixing signal is greater than that of the radio frequency signal. According to the technical scheme, the frequency multiplication amplification circuit is arranged outside the phase-locked loop, the frequency of the output signal of the phase-locked loop can be amplified, the output frequency of the phase-locked loop can be expanded without changing a core circuit in the phase-locked loop, and the frequency multiplication amplification circuit applied to the phase-locked loop is simple in structure.

Synthetic signal creation and management systems and methods for a vehicle include a cloud-based network configured to generate a software policy for a synthetic signal engine and an electronic control unit (ECU) of the vehicle that is configured to receive the software policy from the cloud-based network, configure the synthetic signal engine based on the software policy, execute the synthetic signal engine to create, based on datapoints for two or more foundational vehicle signals, a synthetic vehicle signal, and output the synthetic vehicle signal. The synthetic vehicle signal could comprises concurrent datapoints for the two or more foundational vehicle signals or datapoints for the two or more foundational vehicle signals, respectively, over a specified duration of time. The synthetic signal engine could also be configured to create the synthetic vehicle signal based further on at least one other previously-created synthetic vehicle signal.

This application proposes an ultra-wideband vector modulation phase shifter and phased array system, comprising a cascaded quadrature signal generation circuit, a quadrature error correction circuit, an I-channel amplitude adjustment circuit, a Q-channel amplitude adjustment circuit, and a quadrature signal synthesis circuit. The quadrature signal generation circuit converts the initial differential signal into an I-channel differential signal and a Q-channel differential signal, and outputs the signals to the quadrature error correction circuit. The quadrature error correction circuit corrects the quadrature error of the received differential signal and outputs the corrected I-channel differential signal and Q-channel differential signal. The I-channel amplitude adjustment circuit and the Q-channel amplitude adjustment circuit adjust the amplitude of the received signal and transmit the adjusted signals to the quadrature signal synthesis circuit. The quadrature signal synthesis circuit combines the two received differential quadrature signals into a target differential signal. The integrated generation and correction circuit structure achieves the expansion of the quadrature signal bandwidth, effectively improving the operating bandwidth of the vector modulation phase shifter.

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 present invention discloses a feed network system, belonging to the field of antenna feeding technology. It comprises four 2x2 rectangular arrays of equal-amplitude, 90° network sub-arrays and a power combining network composed of a four-in-one Wilkinson power combiner located at the bottom of the sub-arrays. The four arrays of equal-amplitude, 90° network sub-arrays achieve signal synthesis output through a cascaded four-in-one Wilkinson power combiner. The equal-amplitude, 90° network sub-arrays comprise a first metal ground plate, a first microwave substrate, a first metal signal line, a first prepreg, a second microwave substrate, a second metal ground plate, a second prepreg, a second metal signal line, a third microwave substrate, and a third metal ground plate, stacked sequentially from top to bottom. The microwave substrates are bonded together by prepregs, thereby achieving a feed network capable of connecting four feed points with right-handed equal-amplitude, 90° antenna signals. The present invention reduces the horizontal and lateral dimensions of the feed network, achieving miniaturization and high integration of the antenna array.

The utility model discloses galvanized steel plate heat treatment equipment, belongs to the technical field of steel plate heat treatment, and solves the problems that when the existing steel plate heat treatment equipment is used for carrying out induction heating on a steel plate, the heating quantity is the same when the steel plate with any thickness and width is heated due to the fact that the current is generally kept unchanged. For thin steel plates, the problem of excessive heating may be caused. Comprising a machine shell and a conveying mechanism arranged in the machine shell. When the device is used, a steel plate enters the shell through the conveying mechanism and is subjected to heat treatment through the induction heating coil. The coil control circuit detects the thickness and the width of the steel plate. The width detection module outputs a voltage signal in direct proportion to the width through magnetic field changes. The thickness detection module converts the voltage signal into a voltage signal in inverse proportion to the thickness through a current phase difference. The signals are synthesized to generate comprehensive control voltage, the current amplitude of the induction coil is adjusted, closed-loop control is formed, and excessive heating of the steel plate is avoided.

This invention provides a feedback tracking control method based on scalarized visual frame pixels. First, a dynamic state-space model of a vehicle following system is established and the system state variables are determined. Then, a state feedback tracking controller is designed for the dynamic state-space model. The original image of the leading vehicle is acquired and input into an image signal synthesizer. After processing by the image signal synthesizer, a background image and a standard image are obtained. Next, a binarized digital image pixel mask method is used to scalarize the high-dimensional features of the original image, background image, and standard image of the leading vehicle to obtain the number of pixels of the leading vehicle and the image error, which has an implicit functional relationship with the system state variables. Finally, based on the functional relationship between the image error and the system state variables, the image error is directly fed back to the state feedback tracking controller to control the throttle of the following vehicle, achieving fixed-distance following control.

The invention discloses a millimeter wave radar array-based wind field fan blade integrated monitoring method, which comprises the following steps of: generating a point cloud observation result by performing range direction and Doppler processing on observation data acquired by a millimeter wave radar array at the top of a cabin, and constructing an echo energy time sequence in a fan blade area; and determining the sweep-over period of the fan blade through peak detection. A time slot control sequence is constructed, a fan blade occupation time period is used for point cloud reconstruction, and a non-shielding time period is used for wind measurement. In a fan blade point cloud reconstruction time slot, reconstructing a fan blade point cloud through methods of multi-channel signal synthesis, threshold detection, angle estimation and the like, and extracting blade state parameters; in a wind measurement time slot, a wind speed vector inversion model is established through multi-sight radial speed observation, and the wind speed and the wind direction are obtained by adopting a weighted fusion method. And fusing and outputting the fan blade state parameters and the wind field parameters in a unified coordinate system and a time axis. According to the method, additional wind measurement equipment is not needed, and integrated, continuous and high-reliability monitoring of the wind field and the fan blades is achieved.

The embodiment of the invention belongs to the technical field of microphones, and relates to a self-adaptive microphone gain adjustment method and device, equipment and a storage medium, and the method comprises the steps: receiving an audio gain adjustment request which is transmitted by a user terminal and carries an original audio signal; performing frequency band division operation on the original audio signal to obtain original signal sub-frequency bands; performing noise frequency band identification operation on the original signal sub-frequency bands to obtain a to-be-processed frequency band; performing selective gain operation on the to-be-processed frequency band according to a preset gain strategy to obtain a gain noise frequency band; and performing signal synthesis operation on the gain noise frequency band to obtain a gain audio signal. The microphone noise reduction method effectively solves the problem that a traditional microphone noise reduction method cannot carry out noise reduction on the frequency generating amplification, in addition, the noise frequency band is isolated before gain, and the problem that noise and human voice are synchronously amplified is thoroughly avoided.

The present invention relates to the technical field of radio frequency injection simulation of radar equipment, and discloses a radio frequency injection simulation method for phased array radar based on equivalent inversion of antenna performance. The system adopted by the method includes: a host, an I / O interface adapter unit, and a display control unit. The baseband signal generation unit of the host is connected to the antenna beam forming unit through a baseband signal modulation unit, and the output end of the antenna beam forming unit is connected to the up-conversion input end of the up / down conversion unit through a baseband signal synthesis unit. The up-conversion output end of the up / down conversion unit is connected to the radar under test through a cable. The down-conversion input end of the up / down conversion unit is connected to the excitation end of the radar under test through a cable. The present invention can significantly reduce the number of radio frequency feeding channels required for the simulation system, significantly improve the flexibility of the signal simulation function of the simulation system, enhance the versatility and applicability of the system; improve the application space of simulation technology, and help give full play to the advantages of simulation technology and improve the test cost-effectiveness.

The application discloses a thyristor trigger signal and driving circuit for non-controlled rectification of a direct-current bus voltage, comprising a voltage comparison unit, a pulse wave generation unit, a trigger signal unit and a driving unit; the voltage comparison unit is used for judging a thyristor opening time and sending an output effective level signal to the trigger signal unit; the pulse wave generation unit is used for generating a frequency-adjustable pulse wave and sending the pulse wave to the trigger signal unit; the trigger signal unit is used for synthesizing a trigger signal based on the effective level signal and the trigger signal and sending the trigger signal to the driving unit; and the driving unit is used for controlling conduction of the thyristor based on the trigger signal. The application greatly improves reliability of the thyristor driving, avoids problems of power waste and large loss of a driving power supply, and can be applied to high-power frequency converter products in batches.

The embodiment of the application provides an audio low-frequency signal gain control circuit and a related device, which comprise an input processing sub-circuit, a non-dynamic low-frequency signal processing sub-circuit, a dynamic low-frequency signal processing sub-circuit, a signal synthesis sub-circuit, an adaptive gain control sub-circuit and a bass speaker. The input processing sub-circuit is used for pre-processing an input stereo audio signal to obtain a first audio low-frequency signal; the non-dynamic low-frequency signal processing sub-circuit is used for processing the first audio low-frequency signal to obtain a non-dynamic audio low-frequency signal; the dynamic low-frequency signal processing sub-circuit is used for separating a dynamic audio low-frequency signal; the signal synthesis sub-circuit is used for merging the non-dynamic audio low-frequency signal and the dynamic audio low-frequency signal to obtain an audio low-frequency signal; the adaptive gain control sub-circuit is used for gain control on the audio low-frequency signal; and the bass speaker is used for outputting the audio low-frequency signal. In this way, the adaptive gain on the audio low-frequency signal is realized through an analog circuit.

A signal processing system may include a sensor readout channel configured to convert an electronic signal into a digital quantity. The sensor readout channel may include a sigma-delta modulator having a modulator input and a modulator output, first system-level chopping switches located at the modulator input, an auxiliary path comprising an analog-to-digital converter (ADC) having an auxiliary path input and an auxiliary path output, the auxiliary path input configured to receive as its input signal a signal output by a memory element of the sigma-delta modulator, second system-level chopping switches located downstream of the sigma-delta modulator and the auxiliary path, and a signal combiner configured to combine a modulator output signal generated by the sigma-delta modulator with an auxiliary path output signal generated by the auxiliary path to generate a combined output signal.

The application discloses a feedback cut-off and false alarm detection system, which comprises a signal trigger circuit, a false trigger detection circuit, a timing circuit and a signal synthesis circuit. When there is no specific trigger signal in space, the system is in a dormant state, and standby power consumption is almost zero. When there is a trigger signal in space, and the sum of the trigger signal and a pre-bias voltage is greater than a total switch-on voltage, the circuit is turned on to start working. The false trigger detection circuit can judge the false triggering of a non-specific signal and cut off the circuit when false triggering occurs. The timing circuit can realize the timing cut-off function of the circuit, and cut off the circuit when the working time of the circuit reaches a preset time, and the circuit continues to be dormant. The application has the characteristics of low power consumption, high sensitivity, low false alarm rate and stable closed-loop working of the circuit.

The present invention provides an echo cancellation method in a delay jitter scenario in the field of echo processing technology, comprising: step S10, collecting a far-end signal and a near-end signal; step S20, calibrating and aligning the far-end signal and the near-end signal through a delay calibration module and then inputting them into a linear filtering module; step S30, the linear filter of the linear filtering module outputs a linear filter coefficient and an error signal to a far-end signal synthesis unit based on the far-end signal and the near-end signal; step S40, the far-end signal synthesis unit calculates a far-end reference signal and a delay state based on the linear filter coefficient, and outputs the far-end reference signal, error signal and delay state to a nonlinear suppression module; step S50, the nonlinear suppression module outputs an echo-free signal based on the far-end reference signal, error signal and delay state. The advantages of the present invention are: it realizes compensation for the delay jitter of the echo, greatly improves the echo cancellation effect, and thus greatly improves the call quality.

The invention discloses a local oscillator circuit applied to a radio frequency front end. The local oscillator circuit comprises a phase-locked loop, a phase shifter and a differential converter, the phase-locked loop is connected with the phase shifter, and the phase-locked loop is used for synthesizing an oscillation signal according to an external reference signal and transmitting the oscillation signal to the phase shifter; the phase shifter is connected with the differential converter, and the phase shifter is used for converting an oscillation signal into an orthogonal local oscillation signal and transmitting the orthogonal local oscillation signal to the differential converter; the differential converter is used for converting the orthogonal local oscillator signal into an orthogonal differential local oscillator signal. The phase-locked loop solves the technical problem that an existing phase-locked loop outputs a single-phase signal and cannot directly meet the orthogonal frequency mixing requirement.

The application provides a call noise reduction method, a terminal and a computer readable storage medium. The call noise reduction method comprises the following steps: acquiring a first sound signal collected by a first sound collection module of the terminal and a second sound signal collected by a second sound collection module of a headset during a call, wherein the first sound signal comprises a mixed first voice signal and a first noise signal, and the second sound signal comprises a mixed second voice signal and a second noise signal; separating the first voice signal, the first noise signal, the second voice signal and the second noise signal; processing the first voice signal and the second voice signal to obtain a target voice signal; synthesizing the first noise signal and the second noise signal to obtain a synthesized noise signal; performing noise reduction processing on the synthesized noise signal to obtain a residual noise signal; and synthesizing the target voice signal and the residual noise signal to obtain a call signal. The call noise reduction method provided by the application can realize clearer and more authentic voice calls.