631 results about "Square waveform" patented technology

The invention discloses an eddy current displacement sensor sine constant current source excitation method, and belongs to the technical field of sensor measurement and control. The method comprises the following steps: S1, generating positive and negative symmetric reference voltages through a reference voltage source circuit; s2, outputting a square wave control signal with adjustable frequency by the control chip, and driving a switching circuit to generate a square wave taking the positive and negative reference voltage as a level; s3, processing the square wave through a filter circuit to obtain a standard sine wave voltage signal; and S4, converting the sine voltage signal into sine constant current source excitation through a Howland current source circuit, and outputting the sine constant current source excitation to a sensor probe coil. According to the invention, through combination of digital control and analog conversion, the circuit structure is simplified, the cost is significantly reduced, and convenient adjustment of the output frequency and high stability and precision of the output current are realized at the same time.

The invention discloses an active pen and touch screen interaction system resistant to common-mode interference and a signal demodulation method. The system comprises a signal receiving terminal and a signal transmitting terminal. The signal transmitting terminal modulates data to be transmitted by adopting a differential binary phase shift keying modulation method, and transmits a generated modulation signal to the signal receiving terminal; the analog front-end receiving module is coupled with the signal transmitting terminal, receives the modulation signal and outputs a digital square wave signal after fidelity extraction processing; and the digital demodulation processing module performs differential coherent digital demodulation on the digital square wave signal based on the prior characteristics of the modulation signal, inhibits residual noise and recovers data to be sent. The analog front end focuses strong common-mode noise suppression and analog filtering, the digital demodulation algorithm performs secondary digital purification by using signal time sequence characteristics, and the two constructs an efficient anti-interference pipeline. Meanwhile, the regular square wave signals can be directly processed through differential coherent demodulation, and the requirements for performance and power consumption of a rear-end processor are lowered.

The invention discloses a voltage-to-current circuit, a calibration method, a multi-range calibration method and a power supply, a power amplification unit adopts MOS tubes of different channel types to match with working voltages of opposite polarities, and a bias circuit is combined to superpose exclusive bias, so that the waveform adaptation limitation of a traditional circuit is broken through, and the voltage-to-current conversion efficiency is improved. Alternating current, direct current, triangular waves, square waves and other special waveforms can be stably output, and the adaptability is greatly improved; secondly, pure hardware signal transmission and feedback are carried out in the whole process, the intermediate link of MCU measurement-setting is omitted, multi-stage error accumulation is effectively reduced, output delay is remarkably reduced, and the response speed is higher; in addition, the current sampling feedback unit and the error amplification unit form closed-loop control, power amplification output current is sampled in real time and fed back for calibration, and the precision and stability of the output current are effectively improved. Meanwhile, the bias circuit accurately regulates and controls the conduction state of the MOS tube, the linearity and consistency of current output are improved, and the overall structure is simple and reliable.

The application discloses a display panel driving method, a driving device and a readable storage medium, and relates to the technical field of display, which is characterized in that: an initial response square wave signal is converted based on a current display temperature to obtain a target response square wave signal; a target duty cycle in the target response square wave signal is used to determine a calling requirement, so as to determine a response duration corresponding to a normal output display picture of a liquid crystal display device at the current display temperature; a target response duration parameter table meeting the calling requirement is called; and the display panel at the current display temperature is driven according to the target response duration parameter table, so that the reaction speed of various pixel points to an input display signal at various temperatures is effectively accelerated, and the adverse situation that an animation picture is still blurred and ghosted due to the fact that different temperatures cannot be considered is avoided.

The invention provides a stress detection system and method based on active and passive dual modes, and relates to the technical field of stress detection, and the system comprises a stress sensor and a data processing module which are in communication connection. The stress sensor comprises a first coil assembly, a second coil assembly and a three-axis magneto-dependent sensor. The first coil assembly is configured to apply a square wave current to the first coil assembly through the excitation source to generate an ACSM effect; the data processing module is configured to collect a voltage signal and a phase signal of the second coil assembly under the ACSM effect; collecting a magnetic field signal of the three-axis magneto-dependent sensor; performing feature extraction on the voltage signal, the phase signal and the magnetic field signal to obtain feature data; and inputting the characteristic data into the joint characteristic decoupling mathematical model, and determining the pipeline stress value of the to-be-detected pipeline, so as to solve the problems that an existing stress sensor is large in error during detection in a low-stress area, and the accuracy of a detection result is low due to interference of an environmental magnetic field.

The invention discloses a chip test circuit and system. The circuit comprises a high voltage generation module, a negative voltage generation module, a gate drive module, a switch module, a control module and a comparison module. The high-voltage generation module and the negative-voltage generation module respectively generate a high-voltage signal and a negative-voltage signal; the control module outputs complementary control signals to the gate driving module, and the gate driving module drives the switch module to alternately switch between a high-voltage signal and a negative-voltage signal to generate a square signal and input the square signal to a sampling input end of the chip to be tested; the comparison module compares a signal of the sampling input end with a reference voltage and outputs a corresponding level signal to the control module, so that the control module judges the conduction state of a grid electrode in the chip to be detected. According to the invention, the synchronous rectification control chip of the sealed MOS can be tested, the problem that the control state of the internal grid cannot be tested when the internal grid is not led out is solved, and the test coverage of the control logic of the internal grid of the chip is realized.

The invention discloses a battery deformation monitoring method and device, a storage medium and computer equipment, and the method comprises the steps: enabling a flexible capacitive sensor to be attached to the surface of a target monitoring battery, and sensing the capacitance change caused by the deformation of the battery; the capacitance change is converted into a frequency signal through an LC oscillation circuit; a high-speed comparator is adopted to convert the frequency signal into a square wave; and the microcontroller captures the frequency of the square wave and inversely calculates the capacitance value, the capacitance change rate is calculated by combining a sliding window algorithm, median filtering and a temperature compensation technology, and if the capacitance change rate exceeds a preset threshold value, the battery deforms, so that the high-accuracy and high-reliability real-time monitoring and early warning effects on the battery deformation phenomenon are achieved.

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 present application relates to the technical field of autonomous driving. Disclosed are a clock synchronization system and method. In the system, a global synchronization module achieves clock synchronization of a global computing device on the basis of a clock signal of a navigation device, and sends to a local synchronization module a square wave signal including a timestamp. The local synchronization module completes, on the basis of the timestamp included in the square wave signal, the resetting for a system clock of the local synchronization module. The local synchronization module includes a plurality of local computing devices, wherein when capturing a rising-edge pulse signal, a first local computing device sends a trigger signal to a trigger-type sensor according to a set pulse width and starts timing, such that the trigger-type sensor transmits collected data to the first local computing device, and when a timing duration reaches a set threshold, the first local computing device stops sending the trigger signal; and a second local computing device uses a system clock thereof as a clock source of a non-trigger-type sensor connected thereto. The present application achieves high-precision clock synchronization without requiring gateway support.

The invention discloses an antenna based on phase-only non-uniform time modulation, which comprises a shaped reflector antenna and a phase-only non-uniform time modulation array feed source, the shaped reflector antenna is used for forming cosecant square beams on a pitching surface, and the phase-only non-uniform time modulation array feed source is formed by a plurality of antenna unit arrays. Each antenna unit is cascaded with a time modulation module, and the phase-only non-uniform time modulation array feed source controls each antenna unit through a phase modulation waveform. According to the invention, a phase-only non-uniform time modulation array antenna is used as a feed source to irradiate and form a reflector antenna, and a cosecant square beam is formed on a pitching surface by using the beam forming capability of the reflector antenna, so that the cosecant square beam is formed on the pitching surface at extremely low cost; a phase-only non-uniform time modulation array feed source is utilized to realize low-sidelobe, high-precision and wide-angle scanning of a fundamental wave beam on an azimuth plane, so that two-dimensional high-gain wide-airspace beam coverage is realized.

The invention provides a digital isolator with both high-speed communication and high common-mode transient immunity. The digital isolator comprises a transmitter, a coupling inductor and a receiver, the transmitter comprises an oscillator, a modulation capacitor assembly and a common-mode transient immunity enhancement module; the oscillator is configured to receive a data signal and generate a first differential signal based on the data signal; the modulation capacitor assembly is configured to modulate a code element 0 into a first frequency and modulate a code element 1 into a second frequency; the common-mode transient immunity enhancement module is configured to determine a bias control signal according to the first differential signal; the receiver is configured to receive the second differential signal and obtain a square wave signal based on the second differential signal; obtaining a triangular wave signal based on the square wave signal; obtaining the maximum value of a triangular wave signal according to the falling edge signal of the square wave signal; and obtaining a target data signal based on the maximum value, so as to solve the problem of low communication and common-mode transient immunity performance of the existing digital isolator.

The application discloses a local discharge signal processing method and device under high-frequency square wave voltage, wherein the method comprises the following steps: filtering low-frequency noise signals of a test power supply by using a high-pass filter with a preset cutoff frequency, wherein the test power supply is a high-frequency square wave power supply for local discharge test of an insulation sample; obtaining a local discharge starting voltage of the insulation sample, collecting a local discharge signal when a test voltage is the local discharge starting voltage, obtaining a characteristic frequency band of local discharge of the insulation sample according to the local discharge signal, and the test voltage is a high-frequency square wave voltage of the test power supply; performing modal decomposition on the local discharge signal of the characteristic frequency band to obtain a plurality of modal components, selecting a plurality of modal components satisfying a preset condition to perform noise reduction processing and signal reconstruction, and obtaining a denoised local discharge signal of the insulation sample under the high-frequency square wave voltage. The application can avoid interference of the high-frequency square wave power supply on the local discharge signal, and obtain a local discharge signal with high signal-to-noise ratio under the high-frequency square wave voltage.

The invention relates to the technical field of semiconductor material thermoelectric performance testing, in particular to a bismuth telluride sheet material Seebeck coefficient measuring device. The device mainly comprises a flexible measuring device and a data acquisition system, the data acquisition system is provided with a universal meter and a programmable power supply, the flexible measuring device is connected to the input end of the universal meter through a signal cable to transmit temperature and pressure signals of a thermocouple, and the flexible measuring device is connected to the output end of the programmable power supply through a power supply cable to transmit the temperature and pressure signals of the thermocouple. And the universal meter and the programmable power supply are respectively connected to the computer through communication cables and are connected with the computer to realize data processing. Through the three-in-one design of flexible contact, synchronous sensing and temperature difference control, accurate measurement of the Seebeck coefficient is realized. Through actual measurement, the temperature control precision of the device is + / -0.1 DEG C, the voltage acquisition resolution is 0.1 mu V, and the Seebeck coefficient measurement error is less than 2%.

The invention relates to the field of semiconductor device and integrated circuit research, in particular to a semiconductor device dose rate effect laser simulation system. Multiple wavelengths and a wide energy range are achieved through the optical fiber laser pulse seed source assembly and the solid laser amplifier assembly, the pulse width can range from 1 ns to 100 microseconds, variable complex waveforms such as square waves, rectangular waves, sine waves and pulse strings are achieved, and pulse laser with the energy range from the nanojoule level to the joule level and adjustable wavelengths and waveforms can be output according to requirements. The high-low energy laser adopts a common-path design, so that the system integration degree is improved; light spots are adjustable from centimeter level to micron level, and global irradiation and micro-area positioning and scanning of an irradiation sample can be realized. According to the invention, dose rate effects under different conditions can be accurately and flexibly simulated, the blank of a high-energy, variable-waveform and multi-wavelength dose rate effect laser simulation system is filled up, and an efficient solution is provided for the reliability research of devices under a complex irradiation environment.

This application relates to an infrared detection circuit, method, apparatus, and device. When an infrared signal is received by an infrared receiver, power is supplied to ground through the infrared receiver and a sampling resistor. A corresponding voltage signal is detected at the sampling resistor and coupled to an inverting integrator circuit for integration, yielding a signal of the magnitude of a first voltage signal. This signal is then transmitted to a hysteresis comparator circuit for comparison, ultimately outputting a square wave signal of the magnitude of a second voltage signal to the processor, which identifies the signal. The processor determines the frequency of the output square wave signal based on the first and second voltage signals and then determines the infrared signal intensity based on the frequency, thus achieving infrared signal intensity detection. During operation, this scheme can convert infrared signals of different intensities into square wave signals of corresponding frequencies, thereby enabling the processor to detect infrared signal intensity based on the frequency of the received square wave signal.

The invention provides an amplitude shift keying phase demodulation device, which comprises a zero-crossing comparator used for extracting a zero-crossing point position of a voltage difference between two ends of an output capacitor of a power transmission circuit; the pulse construction circuit is used for constructing a zero crossing point pulse signal by taking the zero crossing point position as a starting point; the phase signal construction circuit is used for generating an original phase signal according to the zero crossing point pulse signal and a square wave sequence output by a power inverter of the power transmitting circuit; and the bit data extraction circuit extracts the pulse width of the original phase signal by using a pulse counter to obtain multi-bit phase information, and obtains a single-bit ASK signal according to a comparison result of the multi-bit phase information. According to the device disclosed by the invention, a digital-to-analog converter commonly used in phase demodulation is directly canceled, the design cost and the production cost are reduced, and meanwhile, the communication quality problem of a large number of communication requirements in a wireless charging process is solved.

The present application relates to a kind of based on square wave signal duty cycle extraction switch converter control method, first extract the duty cycle of target square wave control signal PWM, and in combination with the preset reference voltage V REF It is connected to the working switch converter, and the voltage signal V PWM It is generated, and then filtering processing is carried out, in combination with the feedback voltage V FB Of switch converter, proportional addition processing and proportional amplification processing are carried out, and then the control voltage signal V PWM_FB For being used to control switch converter is obtained;And the corresponding system is designed, including switch module, low-pass filter circuit module, addition and proportional operation circuit module, for realizing each step of the designed method respectively, improve the working efficiency of switch converter, and the specific design circuit is simple, easy to practical application, low in cost, and the application effect is obvious.

The invention discloses a random analog pulse signal generation circuit, which is characterized in that the output of an excitation pulse generation module obeying discrete random time distribution is connected to an excitation pulse generation module obeying continuous random time distribution, and the excitation pulse generation module is used for generating square wave pulses of which the time interval of the front edges of two adjacent excitation square waves obeying discrete distribution; the output of the excitation pulse generation module obeying continuous random time distribution is connected to the analog narrow pulse generation module, and the analog narrow pulse generation module is used for converting the generated square-wave pulse into a square-wave excitation pulse of which the leading edge obeys specific distribution; and the analog narrow pulse generation module is used for converting the leading edge of the square wave excitation pulse into a narrow pulse signal so as to generate a signal waveform suitable for a fast detector electronics system test. According to the circuit, the inherent discreteness of digital logic is eliminated while better programmability of the digital logic is kept, so that the finally output pulse waveform signal is closer to the time characteristic of the signal processed by the detector under the real working condition.

The invention provides an insulation space charge low-voltage side acquisition system under positive polarity square waves. The insulation space charge low-voltage side acquisition system comprises a signal generation unit, a voltage amplification unit, a current-limiting protection resistor, a high-voltage test branch, a signal acquisition unit, an optical fiber communication module and an upper computer, wherein the high-voltage test branch is formed by connecting a tested sample and an integrating capacitor in series; the signal acquisition unit and the optical fiber communication module are integrated on a PCB (Printed Circuit Board); according to the system, a signal generation unit and a voltage amplification unit cooperatively generate repeated square wave high voltage and apply the high voltage to a sample, a signal acquisition unit on a low-voltage side is used for extracting an analog voltage signal on an integrating capacitor, the analog voltage signal is converted into a digital signal and then is transmitted to an upper computer through optical fiber isolation, and a dynamic charge quantity waveform is obtained. The device can accurately measure the charge accumulation characteristics of the insulating material or the structure under the repeated square wave voltage, effectively evaluates the insulating performance and the deterioration degree of the sample, and has the advantages of high measurement precision, good safety, high integration level and the like.

A gas-powered appliance includes a main burner for burning gas, a flame sensor assembly, and a controller. The flame sensor assembly includes a probe positioned proximate the main burner and a detector coupled to the probe to receive an alternating current (AC) input, couple the AC input to the probe and generate a variable pulse width direct current (DC) square wave output having a plurality of pulses. The controller connected is to the flame sensor assembly and includes a processor and a memory. The controller is programmed to control the main burner to burn gas, determine a pulse width of a pulse of the DC square wave, and determine based on the determined pulse width a characteristic of the flame on the main burner with greater precision than some known systems.

The application discloses a three-redundancy angle extraction method based on an SADA photoelectric encoder and belongs to the cross technical field of photoelectric angle measurement and reliability improvement. The method introduces a motor direction control signal DIR on the basis of known A, B, Z and half-turn signals BQ, respectively adds and subtracts the A and B square wave signals, extracts A angle, B angle and AB angle obtained through orthogonal decoding, realizes three hot backup redundancies of angle information, simultaneously uses the jumping edges of the Z signal and the BQ signal to clean A angle, B angle and AB angle, thereby establishes an absolute zero point and realizes double redundancy of the zero position signal. Further differentiating the three angle values can obtain 3 redundancies of angular velocity. The application significantly improves the reliability and fault tolerance of the SADA angle measurement without increasing code channels and is suitable for reliability improvement of angle sensing of similar SADA mechanisms.

The present application relates to a kind of seismic wave impedance diffusion inversion method and device, its essence is a kind of from well site to surrounding diffusion layered structure and attribute inversion method.Core is to use well logging curve to carry out layering etc., then carry out well position inversion, simultaneously, to make the result obtained by well logging interpretation and actual seismic record difference minimum, need to be appropriately disturbed by the square wave type calibration layering curve obtained from well logging interpretation, generate hundreds of reflection coefficient curves, to generate synthetic seismic record, find the synthetic record with actual seismic record difference minimum, the horizon etc. corresponding to this best synthetic record is regarded as the best seed solution and diffuses to all around, during diffusion process, by adding time window or horizon to constrain vertical propagation interval, to obtain the inversion optimum value of entire data set, specific flow as shown in Figure 1.The present application improves the precision of thin layer boundary delineation, and has higher potential for thin layer resolution.

The application provides an extended dual-port RAM communication device based on a PCIE bus and an implementation method, which communicates with a CPU through a PCIE bus, connects with external equipment through an interface, and realizes dual-port RAM communication between the PCIE bus CPU and the external equipment. The application can work independently or in parallel in a far-end mode and a near-end mode. The extended dual-port RAM communication device based on the PCIE bus supports physical connection with a dual-port RAM communication port of the external equipment through a plurality of optional types of interfaces, and matches the electrical characteristics of the dual-port RAM communication physical port of different external equipment. The extended dual-port RAM communication device based on the PCIE bus generates a square wave signal and transmits the square wave signal to the CPU and the external equipment at both ends of the dual-port RAM communication, so that the CPU and the external equipment respectively perform read and write access to the dual-port RAM in the positive half cycle and the negative half cycle of the square wave signal, and the conflict caused by simultaneous read and write of both parties to the same address unit in the dual-port RAM is avoided.

The invention belongs to the technical field of aircraft control, and particularly relates to an optimization method for rotating speed self-inspection of a semi-liquid floated gyroscope, which comprises the following steps of: shaping a self-inspection waveform signal into a square signal by designing a shaping circuit; the high level of the shaped square wave signal is greater than 4.5 V, and the low level of the shaped square wave signal is less than 0.5 V; the frequency is + / -5Hz of the power supply frequency of the gyro motor. By the adoption of the optimization method for self-inspection of the rotating speed of the semi-liquid floated gyroscope, the problem that self-inspection of the rotating speed of the gyroscope motor is out of tolerance is effectively solved, and the reliability of the gyroscope can be remarkably improved after optimization treatment is conducted.

The application provides a pulse current generation circuit, a low-noise frequency reducer and a satellite receiver. The circuit comprises a pulse generation module, a current generation module and a current mirror module, the current generation module is electrically connected with the pulse generation module and the current mirror module, and the current mirror module is used for being electrically connected with an output end of an LDO in the low-noise frequency reducer. The pulse generation module receives a square wave signal and outputs a first pulse voltage at a falling edge of the square wave signal, and the current generation module generates a first current according to the first pulse voltage; the current mirror module outputs a pulse current according to the first current, and the pulse current is a pull-down current connected to the output end of the LDO. The pulse current generation circuit of the application generates and outputs the pull-down pulse current only in the period when the modulation wave needs to drop, effectively reduces the invalid current loss in the period when no demand is required, greatly reduces the average power consumption in the LNB power modulation process, and greatly improves the power conversion efficiency during the LNB power modulation.

The embodiment of the invention provides a power amplifier, a radio-frequency power supply and semiconductor process equipment, and the power amplifier comprises a switching network which comprises a bridge circuit, is connected with a DC power supply and a radio-frequency source, and is used for outputting a radio-frequency signal based on the phase difference of the radio-frequency signal output by the radio-frequency source at the two ends of the bridge circuit, generating square-wave voltage from the direct-current voltage of the direct-current power supply; and the resonance network is connected with the switch network and is used for converting the square wave voltage into sine wave voltage to be output. According to the embodiment of the invention, the output power can be controlled by controlling the phase shift of the gate-source voltage at the two sides of the bridge circuit, or the output power can be controlled by controlling the size of the direct-current voltage of the direct-current power supply, so that the output power control under various conditions is realized, and the response time of the radio-frequency power supply can be shortened.

A contactor detection circuit is disclosed. [Solution] The contactor detection circuit is configured such that the output terminal of a reference voltage generation circuit is connected to the inverting input terminal of the comparator and electrically connected to the two fixed contacts of the contactor in order to input a reference voltage V1 to the inverting input terminal of the comparator. The output terminal of a sampling circuit is connected to the common-mode input terminal of the comparator and the output terminal of a waveform generator is connected to the input terminal of the sampling circuit in order to input a sampling voltage V2 to the common-mode input terminal of the comparator. A periodically changing voltage signal V3 is input to the sampling circuit. When the contactor is open, the sampling voltage V2 output by the sampling circuit is a periodic waveform, causing the comparator to output a periodic square wave signal. When the contactor is closed, the sampling voltage V2 output by the sampling circuit is higher than the reference voltage V1, causing the comparator to output a high level.

The invention provides a detection method and device for a high-voltage safety circuit, electronic equipment and a storage medium. The method comprises the steps that a high-voltage safety signal of the high-voltage safety circuit of an elevator is sampled in real time; converting the high-voltage safety signal into a first low-voltage signal and a square wave signal, and converting the first low-voltage signal into a voltage actual value; according to the actual voltage value, the square wave signal, a preset first voltage threshold value and a preset detection time threshold value, whether the high-voltage safety circuit breaks down or not is judged; and if the high-voltage safety circuit has a fault, triggering a fault alarm process. An analog quantity and digital quantity dual checking mechanism is adopted to carry out fault detection on the high-voltage safety circuit of the elevator, the accuracy and timeliness of fault detection of the high-voltage safety circuit are ensured, and therefore the risk of arc discharge of an operation contactor is avoided.

The invention discloses a ferromagnetic material displacement measurement method and device based on PWM waves and a phase method. The method comprises the steps that two paths of same-frequency PWM square wave signals are generated; applying the excitation signal to the electromagnetic induction probe, and based on the relative displacement between the electromagnetic induction probe and the ferromagnetic material, obtaining an induction signal which is output by the electromagnetic induction probe and whose phase changes with the relative displacement; converting the induction signal into a third PWM square wave signal, wherein the phase of the third PWM square wave signal is related to the phase of the induction signal; performing logic AND operation on the third PWM square wave signal and a reference signal to generate a pulse signal; and filtering the pulse signal to obtain a displacement measurement result proportional to the relative displacement. The single-chip microcomputer is adopted to generate high-frequency PWM waves, the phase method and digital logic processing are combined, magnetic field interference and signal drifting in ferromagnetic material measurement are effectively restrained, high precision and high dynamic response are guaranteed, and meanwhile system complexity and cost are remarkably reduced.

This invention discloses a method for precursor ion scanning in a digital ion trap mass spectrometer, relating to the field of mass spectrometry analysis technology. The method includes: applying a bipolar square wave radio frequency signal with frequency scanning to the ion trap electrode; applying a y-direction auxiliary AC signal to the ion trap electrode, the frequency of which is a fixed division ratio of the radio frequency signal, used to resonate and fragment precursor ions with a specific mass-to-charge ratio at a fixed value during the scanning process; applying an x-direction auxiliary AC signal to the ion trap electrode, the frequency of which is dynamically adjusted according to the mass-to-charge ratio of the target characteristic product ion to match the resonance frequency of the product ion in real time, thereby selectively expelling it; and finally, by detecting the expelled characteristic product ions, obtaining the spectra of all precursor ions that can produce the fragment. This invention achieves efficient and accurate precursor ion screening within a single trap, and is particularly suitable for the rapid on-site detection of novel compounds without a standard spectral library.