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CN-121980296-A - Low-power-consumption magnetic field sensing and transmission integrated method of full-simulation framework

CN121980296ACN 121980296 ACN121980296 ACN 121980296ACN-121980296-A

Abstract

The invention discloses a low-power consumption magnetic field sensing and transmission integrated method of a full-simulation framework, wherein a sensing stage utilizes a two-channel TMR sensor which is arranged in an orthogonal mode to collect magnetic leakage signals, two channels are processed in parallel through a simulation addition and a differential circuit, a peak value detection and simulation comparison logic is used for adaptively selecting an analog voltage signal with optimal amplitude, and meanwhile, corresponding binary level is generated according to amplitude high-low mapping, so that blind area elimination and coding are completed from a physical layer. And in the transmission stage, a nonlinear device is utilized to passively extract a difference frequency component from an external double-chirp excitation signal, a stable clock is obtained through resonance filtering and normalization, and an optimal analog voltage signal output in the sensing stage is directly mixed with the clock for modulation, so that a radio frequency switch is driven to realize passive backscatter transmission. The receiving end completes synchronization based on the known up-chirp sequence, compresses the back scattering signal to the baseband through de-chirp and down-conversion, and then restores the binary bit stream at the node side through resampling and self-adaptive threshold judgment.

Inventors

  • GUO XIUZHEN
  • TAN LONG
  • CHEN XU
  • CHEN JIMING
  • SHU YUANCHAO

Assignees

  • 浙江大学

Dates

Publication Date
20260505
Application Date
20260407

Claims (10)

  1. 1. The low-power consumption magnetic field sensing and transmission integrated method of the full-simulation framework is characterized by comprising the following steps of: The two mutually perpendicular TMR sensors sense magnetic leakage signals, and the output voltages are input into an addition circuit and a differential circuit to perform self-adaptive signal fusion; Modulating an output signal at a node side, namely extracting a low-frequency differential component of an excitation carrier wave as a stable clock by adopting a double-chirp signal with stable frequency offset as an excitation source, modulating a signal to be transmitted and a frequency shift clock, and then carrying out back scattering communication; after receiving the back scattering signal at the node side, the receiving end uses the chirp signal transmitted by the exciting end as a synchronous preamble, and realizes the reconstruction of the binary bit stream of the transmitting end through synchronization, signal compression and baseband recovery.
  2. 2. The integrated method for sensing and transmitting the magnetic field with low power consumption of a full analog architecture according to claim 1, wherein the peak detection is realized by an analog circuit consisting of a diode and a filter capacitor, when the amplitude of an input signal is higher than the voltage at two ends of the capacitor, the diode is forward-turned on and rapidly charges the capacitor to enable the voltage of the capacitor to follow the peak of the signal, and when the input signal falls back, the diode is reversely turned off to prevent the backflow of charges, so that the capacitor maintains the current highest voltage value.
  3. 3. The method for integrating low-power-consumption magnetic field sensing and transmission of a full analog architecture according to claim 1, wherein the peak comparison is specifically that a peak signal is compared with another channel signal through a comparator to generate a control signal to drive an analog switch, and an output signal is subjected to amplitude mapping in a threshold decision mode, wherein when the signal amplitude exceeds a preset reference threshold value, a high level is output, otherwise a low level is output, selection of the output signal is realized, and a final output end only comprises a high discrete logic level and a low discrete logic level.
  4. 4. The integrated low-power consumption magnetic field sensing transmission method of full analog architecture according to claim 1, wherein the dual chirp signal with stable frequency offset is specifically composed of two chirp signals with identical bandwidth, consistent spreading factor and frequency offset.
  5. 5. The integrated method for low-power consumption magnetic field sensing and transmission of full-analog architecture according to claim 1, wherein the step of extracting the low-frequency differential component of the excitation carrier wave is specifically performed by first entering a diode after the excitation carrier wave is received by an antenna, so that multiple chirp frequency components and sum frequency components are generated in the output signal, and meanwhile, a constant difference frequency component is generated, wherein the low-frequency differential component is used as a stable clock.
  6. 6. The integrated low-power-consumption magnetic field sensing and transmitting method of full analog architecture according to claim 5, wherein the stable clock is further required to perform frequency selective resonance, the low-frequency differential component is isolated and amplified by a resonant LC filter circuit, and the resonance frequency is that of the LC resonant circuit.
  7. 7. The integrated method for sensing and transmitting the magnetic field with low power consumption of a full analog architecture according to claim 1, wherein the back-scattering communication is performed after modulating the signal to be transmitted and the frequency shift clock, specifically, modulating the signal to be transmitted and the frequency shift clock signal input to a multiplier to form a modulated signal, and multiplying the binary magnetic flux leakage signal and the frequency shift clock of 1bit by a nand gate of 1bit to form a 2FSK modulated signal containing the magnetic flux leakage signal, wherein the 2FSK modulated signal is used as a control signal to be input to a radio frequency switch to control back-end load switching, so as to realize the back-scattering communication.
  8. 8. The method for integrated transmission of low power consumption magnetic field sensing of full analog architecture according to claim 1, wherein the synchronization process is implemented by calculating a cross-correlation between the received signal and the known chirp signal, specifically, when the received signal is aligned in time with the local reference chirp signal, a cross-correlation function thereof takes a maximum value at a corresponding time delay, thereby estimating a time offset of the received signal with respect to the reference chirp according to a cross-correlation peak position, and implementing time synchronization by performing corresponding time compensation and realignment on the received signal.
  9. 9. The method for integrating magnetic field sensing and transmission with low power consumption of full analog architecture as set forth in claim 1, wherein the signal compression is specifically implemented by multiplying the received signal with a down-chirp signal that keeps consistent in sweep slope and symbol duration after synchronization is completed, thereby converting an up-chirp component of original chirp into a constant frequency back-scattered signal, then performing down-conversion processing on the received signal, shifting its frequency spectrum to baseband, and performing a down-sampling operation.
  10. 10. The method for integrating low-power-consumption magnetic field sensing and transmission of full-analog architecture according to claim 9, wherein the baseband recovery specifically comprises the steps of performing threshold decision on a down-sampled baseband signal to recover a 1-bit coding sequence at a sensing node side, adaptively dividing signal amplitude by adopting a K-means clustering algorithm, automatically dividing samples into two types and determining a dynamic threshold, mapping a part higher than the threshold into 1, and mapping a part lower than the threshold into-1, thereby reconstructing a binary bit stream consistent with node side coding.

Description

Low-power-consumption magnetic field sensing and transmission integrated method of full-simulation framework Technical Field The invention relates to the field of low-power-consumption Internet of things, in particular to a low-power-consumption magnetic field sensing and transmission integrated method of a full-simulation framework. Background Along with the development of the Internet of things and non-contact detection technology, the magnetic flux leakage signal-based precise equipment monitoring application is increasingly wide. For example, leakage field changes during motor and transformer operation are indicative of key failure characteristics such as rotational speed fluctuations, bearing wear, etc. If the information can be obtained in real time, the predictive maintenance of the health state of the equipment can be realized, hidden danger can be found in time, unexpected shutdown can be avoided, and therefore the operation and maintenance cost is obviously reduced. Tunneling magneto-resistance (TMR) sensors are core devices for such non-contact detection by virtue of their high sensitivity and miniaturized nature. However, its inherent directional sensitivity makes it prone to inductive dead zones in the face of complex and variable leakage fields. In order to obtain the sensing data of omnidirectional high fidelity, the prior proposal is characterized in that an analog-to-digital converter (ADC) and a Microcontroller (MCU) are used for carrying out digital fusion of multichannel signals. The complex digital processing architecture solves the problem of dead zones, but greatly increases the power consumption of the sensing front end, and is difficult to meet the requirement of long-term continuous monitoring of the micro node. In addition, the sensing node also needs to have wireless backhaul capability. The backscattering communication is the first choice for data transmission in such resource-constrained scenarios because the backscattering communication does not require active transmission of radio frequency signals. However, this technique faces a serious co-channel self-interference challenge, and in order to obtain a stable communication link, a conventional scheme introduces a local oscillator to generate a frequency offset to avoid interference. Unfortunately, the continued operation of the local oscillator also brings a non-negligible additional energy consumption, shortening the device lifecycle and increasing maintenance costs. In summary, the existing wireless sensing node generally falls into the dilemma of "digital stacking" in architecture, and both the MCU introduced to eliminate the inductive dead zone and the local oscillator introduced to suppress the communication interference become key bottlenecks for limiting the energy efficiency of the system. Therefore, a need exists for a sensing system that breaks the conventional full-analog architecture, and can directly realize adaptive fusion and passive frequency shift transmission of magnetic flux leakage signals in an analog domain on the premise of thoroughly discarding an ADC, an MCU and a local oscillator, thereby truly having high robustness and extremely low power consumption. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a low-power-consumption magnetic field sensing and transmitting integrated method of a full-simulation framework. The invention aims at realizing the technical scheme that the low-power-consumption magnetic field sensing and transmitting integrated method of the full-simulation framework comprises the following steps of: The two mutually perpendicular TMR sensors sense magnetic leakage signals, and the output voltages are input into an addition circuit and a differential circuit to perform self-adaptive signal fusion; Modulating an output signal at a node side, namely extracting a low-frequency differential component of an excitation carrier wave as a stable clock by adopting a double-chirp signal with stable frequency offset as an excitation source, modulating a signal to be transmitted and a frequency shift clock, and then carrying out back scattering communication; after receiving the back scattering signal at the node side, the receiving end uses the chirp signal transmitted by the exciting end as a synchronous preamble, and realizes the reconstruction of the binary bit stream of the transmitting end through synchronization, signal compression and baseband recovery. The peak detection is realized by an analog circuit formed by a diode and a filter capacitor, wherein when the amplitude of an input signal is higher than the voltage at two ends of the capacitor, the diode is forward-connected and rapidly charges the capacitor to enable the voltage of the capacitor to follow a signal peak, and when the input signal falls back, the diode is reverse-cut to prevent charge from flowing back, so that the capacitor maintains the current highest voltage value. Th