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CN-122026932-A - Low-frequency electric wave time service signal enhancement receiving intelligent tuning system and method for terminal

CN122026932ACN 122026932 ACN122026932 ACN 122026932ACN-122026932-A

Abstract

The invention relates to the technical field of terminal low-frequency electric wave time service signal processing, in particular to an intelligent tuning system and method for enhancing and receiving a low-frequency electric wave time service signal of a terminal. The invention replaces the traditional fixed time service antenna with an antenna mechanism capable of automatically adjusting the posture, is matched with a six-axis posture sensor and a driving module, monitors the signal receiving quality in real time by the system, automatically drives the antenna to adjust the azimuth and the posture when detecting that the current signal quality is degraded and the receiving state is poor, traverses and searches and accurately locks the optimal receiving position, and gets rid of the restriction of the installation scene and the azimuth on the signal receiving. Meanwhile, a multistage anti-interference signal conditioning circuit is arranged in a matched mode, high common mode rejection amplification, customized narrow band-pass filtering shaping and differential driving output are sequentially completed on an original signal received by an antenna, power frequency common mode interference, broadband clutter, low-frequency baseline drift and ground wire loop interference are effectively inhibited, and time service signal high-fidelity, transmission stability and demodulation reliability are guaranteed.

Inventors

  • ZHANG MENG
  • XU JINWEI
  • MA BO
  • ZUO YONG
  • ZHANG YI
  • WU DI

Assignees

  • 安徽南瑞中天电力电子有限公司

Dates

Publication Date
20260512
Application Date
20260323

Claims (10)

  1. 1. The multistage anti-interference signal conditioning circuit for the low-frequency electric wave time service signals is characterized by comprising a common mode rejection amplifying stage, a precise filtering shaping stage and a differential driving output stage which are sequentially cascaded and used for signal unidirectional transmission; The common mode rejection amplifier stage is an AD8422 instrument amplifier, the common mode rejection ratio of which is not lower than 140dB, and is used for extracting 68.5kHz differential mode time service signals from the mixed signals received by the antenna and suppressing common mode noise; The precise filtering shaping stage is a voltage-controlled voltage source type fourth-order active band-pass filter constructed based on a TLV272 double-channel operational amplifier, and is formed by directly cascading a second-order high-pass filter and a second-order low-pass filter, the center frequency is 68.5kHz, the passband is 1kHz, and the precise filtering shaping stage is used for filtering broadband interference and low-frequency baseline drift, and amplifying and waveform shaping time service signals; the differential driving output stage is an AD8476 precision differential amplifier and is used for converting a single-ended time service signal output by the front stage into a differential signal, realizing signal format matching with a rear-stage demodulation module and inhibiting common mode interference caused by ground wire circulation.
  2. 2. The multistage anti-interference signal conditioning circuit for low-frequency electric wave time service signals is characterized in that an AD8422 instrument amplifier is provided with an external gain adjusting resistor, the amplitude of signals in 68.5kHz differential mode time service is controlled through the resistance value of the gain adjusting resistor, the amplification requirement of signals less than or equal to-80 dBm input by an antenna end is adapted, the voltage amplification factor of a voltage-controlled voltage source type fourth-order active band-pass filter is 2.5, the upper limit cut-off frequency is 69.5kHz, the capacitance parameters and the resistance parameters of the second-order high-pass filter and the second-order low-pass filter are different, the two high-order high-pass filter and the second-order low-pass filter are integrated on the same circuit board, and the two high-order high-pass filter and the second-order low-pass filter are electrically connected with two independent channels of 272 TLV in a one-to-one correspondence mode.
  3. 3. The multistage anti-interference signal conditioning circuit for low-frequency electric wave time service signals according to claim 1 or 2, wherein a differential signal output end of the AD8476 precision differential amplifier is directly and electrically connected with a differential signal input end of a CME6005 electric wave clock receiving demodulation chip, linearity error of an output signal is less than or equal to 0.1%, drift coefficient is less than or equal to 5 mu V/DEGC, and power supply ends of chips of a common mode rejection amplifying stage, a precision filter shaping stage and a differential driving output stage are all provided with power supply filter capacitors.
  4. 4. An intelligent tuning system for enhancing reception of low-frequency electric wave time signals, which is characterized by comprising the multi-stage anti-interference signal conditioning circuit for low-frequency electric wave time signals as claimed in any one of claims 1-3, a preposed multi-axis intelligent antenna and self-adaptive attitude calibration structure, a micro control unit and a demodulation module; the multi-axis intelligent antenna is electrically connected with the signal output end of the self-adaptive gesture calibration structure and the signal input end of the common mode rejection amplifying stage, the signal output end of the differential driving output stage is electrically connected with the demodulation module, the demodulation module is a CME6005 electric wave clock receiving demodulation chip, and the micro control unit is respectively and bi-directionally electrically connected with the multi-axis intelligent antenna, the self-adaptive gesture calibration structure, the multi-stage anti-interference signal conditioning circuit and the demodulation module to realize the working state control, the data acquisition and the interaction of each module.
  5. 5. The intelligent tuning system for enhancing receiving of low-frequency electric wave time service signals is characterized in that the multi-freedom-degree receiving platform with the three-dimensional space adjustment function is composed of an antenna, an electric base, an angle sensor and a driving module, wherein the antenna is arranged on the electric base, the electric base is provided with a Z-axis linear telescopic function, the driving module is a stepping motor or a servo motor and is used for driving the antenna to achieve rotation angle adjustment around X, Y axes, the angle sensor is a six-axis attitude sensor and is used for collecting attitude angle data of the antenna in X, Y, Z three axes in real time and transmitting the attitude angle data to a micro control unit.
  6. 6. The intelligent tuning system for enhancing receiving of low-frequency electric wave time service signals according to claim 5 is characterized in that a multi-axis intelligent antenna and a self-adaptive posture calibration structure are integrated with a limit protection device, a self-locking mechanism and a shock absorber, wherein the limit protection device is arranged at the limit positions of a telescopic end of an electric base and a X, Y-axis rotary joint and is electrically connected with a micro control unit to realize over-position protection, the micro control unit supports two working modes of manual debugging and automatic calibration, and optimized antenna posture parameters are stored as configuration templates.
  7. 7. A closed loop adjusting method for low frequency electric wave time service signal quality, characterized in that an intelligent tuning system for enhancing receiving of low frequency electric wave time service signal according to any one of claims 4-6 is applied, comprising the following steps: the micro control unit cooperates with a CME6005 wave clock receiving demodulation chip to collect the core quality index of the 68.5kHz time service signal which is received by the multi-axis intelligent antenna and processed by the multi-stage anti-interference signal conditioning circuit in real time; the micro control unit inputs the collected core quality index into a built-in dynamic weighting scoring model, and distributes differential weights for each index according to the system operation stage to generate a signal comprehensive quality score; The micro control unit synchronously executes the antenna gesture self-adaptive regulation decision and the time service effectiveness arbitration decision according to the comprehensive quality score; And (3) closed loop verification continuous feedback, namely monitoring the execution effect of the double decisions in real time by the micro control unit, and taking effect data as the basis of the next round of signal quality acquisition and fusion evaluation to form a full-link closed loop regulation of perception-evaluation-decision-execution-verification.
  8. 8. The method for closed-loop adjustment of low-frequency electric wave time service signal quality according to claim 7, wherein the core quality index comprises a received signal strength indication RSSI, a bit error rate BER and carrier phase continuity, wherein the RSSI is used for reflecting 68.5kHz time service signal energy input by an antenna end, the BER is a bit error rate of a time service signal decoding frame counted by a CME6005 electric wave clock receiving demodulation chip, and the carrier phase continuity is obtained by analyzing zero crossing jitter or PLL tracking residual error of a 68.5kHz carrier wave and is used for judging whether the signal suffers burst interference or frequency offset.
  9. 9. The method for closed-loop adjustment of low-frequency wave time service signal quality according to claim 7, wherein the execution logic of the antenna attitude self-adaptive regulation decision is that an initial stage uses RSSI as a guide to control a driving module to drive an antenna to scan a large range of attitudes in a limited angle range according to a preset step length, and a steady stage uses BER and carrier phase continuity as criteria to control the antenna to conduct sub-level fine adjustment to restrain decoding jitter.
  10. 10. The method of claim 7, wherein the timing validity arbitration decision has an execution threshold of RSSI > -85dBm, BER <10 -4 , carrier phase jitter < + -2 DEG, and when three indexes are satisfied at the same time, the micro control unit determines that the current demodulation result is valid timing, and instructs to update the local real-time clock of the system, and if any index is not satisfied, the micro control unit maintains the time reference of the last valid time, and triggers the abnormal recovery flow of the adaptive regulation of the antenna gesture, and the retrospective history valid gesture template restarts the antenna gesture search in combination with the current environment parameter.

Description

Low-frequency electric wave time service signal enhancement receiving intelligent tuning system and method for terminal Technical Field The invention relates to the technical field of terminal low-frequency electric wave time service signal processing, in particular to an intelligent tuning system and method for enhancing and receiving a low-frequency electric wave time service signal of a terminal. Background The low-frequency electric wave timing technology (represented by BPC68.5kHz low-frequency timing signals) is a core means for realizing high-precision unified timing in the fields of electric power automation, industrial instruments, smart grids and the like, has the advantages of no need of a network, autonomous controllability, low power consumption, high stability and the like, and becomes a key support for time synchronization in complex industrial scenes. The 68.5kHz low-frequency time service signal naturally has the characteristics of weak field intensity (usually less than or equal to-80 dBm) and weak anti-interference capability, and is extremely easy to be submerged by 50/60Hz power frequency common mode interference, broadband clutter, impulse noise and low-frequency baseline drift in strong electromagnetic environments such as transformer substations, factory workshops and the like, so that signal distortion and demodulation failure are caused, and the reliability and the precision of a time service system are directly restricted. When the existing low-frequency electric wave time service front-end signal conditioning circuit is used for coping with 68.5kHz weak time service signals and industrial strong interference environments, the performance short plates of all the component modules are gradually accumulated, and finally the core limitation of the integral structure is formed: firstly, a general operational amplifier adopted in a signal amplification link has low common mode rejection ratio, is difficult to effectively isolate 50/60Hz power frequency common mode interference and ground loop noise, cannot accurately separate weak differential mode time service signals from mixed noise, has the defects of large input mismatch, high temperature drift, high noise density and the like, and further deteriorates weak signal quality; on the basis, the filtering and shaping link mostly uses a wide-passband passive or universal active filtering topology, the accurate narrow-band bandpass filtering with the center frequency of 68.5kHz and the passband of 1kHz cannot be realized aiming at the characteristics of 68.5kHz time service signals, the filtering effect on broadband clutter, pulse interference and low-frequency baseline drift is insufficient, the filtering and signal amplification functions are separated, the signal amplification and waveform shaping are difficult to synchronously complete, the signal to noise ratio and the fidelity of output signals are difficult to guarantee, and finally, the signal output link continues the traditional single-ended output form, so that the ground wire circulation interference is easily caused in a transmission path, the ground wire circulation interference cannot be accurately matched with the differential input format of a post-stage demodulation module, noise and distortion are secondarily introduced into the signal conditioned by a pre-stage in the transmission stage, the 68.5kHz useful signal is submerged by interference and waveform distortion as a whole, the demodulation success rate and the time service reliability are seriously reduced, and the core requirements of the high-fidelity signal conditioning of industrial scenes cannot be met. Even though the anti-interference performance of the front-end signal conditioning circuit is improved, the traditional electric wave time service system still has a remarkable short board on the antenna receiving and integral integrating layer, the traditional time service antenna adopts a fixed ferrite magnetic bar structure, the receiving effect is highly dependent on the installation direction and the position, the gesture cannot be dynamically adjusted in scenes with serious signal attenuation such as a metal cabinet and an underground machine room, the condition of receiving failure is extremely easy to occur, meanwhile, the system lacks an intelligent gesture tuning module for integrated driving and angle sensing, only can rely on manual adjustment, the efficiency is low, the dynamic change of the environment cannot be adapted, and the signal conditioning, antenna driving and demodulation modules are arranged separately, so that the integral cooperative control is lacked, the integral receiving, conditioning and demodulation anti-interference link is difficult to be constructed, and the environment adaptability of the whole system is further restricted. Even if a high anti-interference signal conditioning circuit and an intelligent attitude adjustable antenna are equipped, an obvious short board still e