Voltage-Controlled Crystal Oscillator Frequency Adjustment Method Based on Public Network Signal Scanning

Abstract

The present invention discloses a method for adjusting the frequency of a voltage-controlled crystal oscillator (VCXO) based on public network signal scanning, which includes signal scanning, signal capture, generation of the voltage control voltage, adjustment of the voltage control voltage, closed-loop feedback and stability enhancement, and frequency protection. The VCXO can ensure the synchronization and correctness between various parts, reducing time deviation and jitter problems. The method for adjusting the frequency of the VCXO based on public network signal scanning ensures a high degree of consistency between the local clock and the base station clock, thereby effectively avoiding problems such as signal demodulation errors and reduced sampling efficiency caused by clock frequency offset. Through circuit design and algorithm optimization, autonomous synchronization without a GPS module has been successfully achieved, greatly reducing the hardware cost of the device. Through an efficient synchronization algorithm and a low-power circuit design, while maintaining high-precision synchronization, the power consumption of the device has also been effectively controlled. This not only extends the battery life of the device but also improves the overall energy efficiency of the device.

Description

Technical Field

[0001] The present invention relates to the field of voltage-controlled crystal oscillator (VCXO) frequency adjustment, and more particularly to a VCXO frequency adjustment method based on public network signal scanning. Background Art

[0002] In the field of public network signal acquisition, the stability and accuracy of device performance are crucial. However, a long-standing technical problem in this field is that public network signal acquisition devices often experience errors during signal demodulation or a significant reduction in sampling efficiency due to the frequency offset (frequency deviation) between their local clocks and base station clocks. This frequency deviation problem not only affects the accuracy of data acquisition but also severely restricts the overall performance and application scope of signal acquisition devices.

[0003] To address this challenge, the industry has traditionally adopted various solutions. One solution is to rely on external GPS signals to synchronize the local clock. Although GPS signals can provide relatively accurate clock synchronization in open environments, in indoor environments or when there are obstructions, GPS signals are often unable to be effectively received, resulting in clock synchronization failure. In addition, introducing a GPS module increases the hardware cost of the device, which is undoubtedly a significant burden for cost-sensitive application scenarios. Another solution is to use a phase-locked loop (PLL) circuit for clock synchronization. The PLL circuit attempts to lock the local clock to the frequency of the base station clock through complex filter designs. However, this solution also has many drawbacks. First, the design of the PLL circuit is relatively complex and requires precise filter parameter settings to ensure the stability of clock synchronization. Second, the response speed of the PLL circuit is relatively slow. When the base station clock frequency changes, the PLL circuit takes a long time to relock, which is difficult to meet the application requirements of multi-band fast switching.

[0004] Therefore, traditional solutions all have certain limitations and deficiencies when dealing with the clock synchronization problem of public network signal acquisition devices. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present application provides a VCXO frequency adjustment method based on public network signal scanning to solve the above-mentioned technical problems of slow response speed and difficulty in adapting to multi-band fast switching.

[0006] To achieve the above object, the present application provides the following technical solution: A VCXO frequency adjustment method based on public network signal scanning, comprising:

[0007] S1: Signal Scanning

[0008] Using a scanning system, scan the public network frequency band. The RF front-end component has sufficient bandwidth to cover all or part of the range of the public network frequency band, so as to be able to receive wireless signals from different frequency points. During the scanning process, preprocess the received wireless signals, including filtering, amplification, and analog-to-digital conversion, to extract the effective signal components that may contain the synchronization signal of the target base station, and analyze the preprocessed signals to identify and capture the synchronization signal of the target base station.

[0009] S2: Signal capture

[0010] After successfully capturing the synchronization signal, calculate the peak value, which reflects the matching degree between the synchronization signal and the locally generated reference signal, and is used to evaluate the strength and reliability of the signal. Record and output the relevant peak value of the synchronization signal and its position information in the time domain and / or frequency domain, including the specific time point when the synchronization signal appears, the frequency offset, and the relative position relative to the scanning starting point, so as to provide detailed information about the status of the target base station.

[0011] S3: Voltage-controlled voltage generation

[0012] Extract the carrier frequency deviation from the processed digital baseband signal. The carrier frequency deviation represents the difference between the carrier frequency of the received signal and the reference carrier frequency generated by the local oscillator. Its extraction involves continuous monitoring and analysis of the signal phase change, calculate the frequency error of the local crystal oscillator, convert the deviation value into a percentage error or an absolute frequency deviation value relative to the nominal frequency of the local crystal oscillator, and output the frequency error information of the local crystal oscillator for subsequent calibration, compensation, and recording.

[0013] S4: Voltage-controlled voltage adjustment

[0014] Input the information value obtained in step S3 into the PID controller to generate a voltage-controlled voltage adjustment amount, and load the value to the voltage-controlled terminal of the VCXO module through the DAC module to adjust the output frequency.

[0015] S5: Closed-loop feedback and stability enhancement

[0016] Monitor the convergence state of the adjusted frequency in real time. If it exceeds the threshold, trigger the resynchronization process; when the signal is lost, enable the hold mode to maintain the historical data and maintain short-term stability.

[0017] S6: Frequency protection

[0018] Turn on the electromagnetic field shielding device for frequency protection.

[0019] Preferably, in step S1, the synchronization signal includes a primary synchronization signal, a secondary synchronization signal, and a signal pattern for base station identification and time synchronization. The primary synchronization signal is also used to achieve coarse time synchronization between the UE and the base station, laying a foundation for subsequent processes such as fine synchronization and channel estimation. The secondary synchronization signal is used in conjunction with the primary synchronization signal to achieve precise synchronization between the UE and the base station. After capturing the primary synchronization signal, the UE will further search for the secondary synchronization signal to improve the signal accuracy, help the UE accurately identify the base station, and achieve precise time synchronization with the base station.

[0020] Preferably, in step S3, the information is represented in digital form, including a timestamp, a deviation type, and specific error values. The frequency information represented in digital form can achieve higher precision and stability. The development of digital signal processing technology has made it possible to precisely control the frequency. Through digital algorithms, the frequency can be finely tuned to meet extremely high precision requirements. In communication, measurement, and control systems, a high-precision frequency source is crucial for ensuring signal synchronization, improving the reliability and accuracy of data transmission. The voltage-controlled crystal oscillator can stably output a frequency signal that meets the requirements through digital control, enabling the voltage-controlled crystal oscillator to easily communicate with other digital devices and achieve automatic control. The digitally controlled voltage-controlled crystal oscillator can be easily integrated into various digital systems to improve the overall performance and reliability of the system.

[0021] Preferably, in step S6, the electromagnetic field shielding device includes a metal shielding cover configured outside the crystal oscillator. The metal shielding cover can ensure the accuracy of the crystal oscillator's output frequency, thereby ensuring the correct execution of the system's timing logic, reducing data transmission errors or losses caused by unstable crystal oscillator frequencies, and improving the communication performance of the system.

[0022] Preferably, in step S4, the PID controller is used to maintain the stable state of the controlled object, improve the control accuracy of the system, achieve automatic control and response speed of complex process parameters, and adjust the output of the controller according to the magnitude of the current error. When the error is large, the output signal is also large, thereby accelerating the response speed of the controlled object. Proportional control can make the system quickly approach the set value and adjust the output of the controller according to the amount of error accumulated over time. Eliminate the steady-state error of the system and ensure that the system finally stabilizes near the set value. The role of integral control is similar to accumulating errors and continuously adjusting the output, and adjusts the output of the controller according to the rate of change of the error. Predict the future state change trend of the system, thereby reducing overshoot and improving the stability of the system. The introduction of derivative control can suppress the oscillation of the system and is adjusted according to the input and output data of the system, so it has strong adaptability and flexibility.

[0023] Preferably, in step S4: The DAC module is a digital-to-analog converter, which is used to process the input digital signal, including filtering, amplification, and digital signal processing algorithms. It is responsible for processing the input digital signal, such as filtering, amplification, and digital signal processing algorithms, converting the digital signal into an analog signal, generating a corresponding analog voltage or current according to the input digital code, and being responsible for filtering, amplification, etc. of the output analog signal to ensure the quality and stability of the signal.

[0024] Preferably, in step S5: Hold mode: The system calculates the drift of the crystal oscillator output frequency using previously collected data and model parameters, and performs self-correction compensation. Using the frequency drift model trained with historical data accumulated in the locked state, it estimates the trend of frequency output change, and uses the estimated value to compensate the actual output frequency, thereby maintaining the accuracy of the frequency.

[0025] Preferably, in step S5: The voltage-controlled voltage adjustment includes a pre-adjustment circuit, and adjusts the capacitance component, the current near the crystal, and temperature compensation according to the system settings when the signal is lost. The device parameters are automatically adjusted through the pre-adjustment circuit, thereby greatly improving the overall automation of the device.

[0026] Preferably, the scanning system includes a signal acquisition module, a synchronization error extraction module, a voltage-controlled voltage generation module, a VCXO module, and a feedback control module. The public network frequency band is scanned through the scanning system.

[0027] Preferably, the signal acquisition module is used for data acquisition functions, signal conditioning and conversion. The synchronous error extraction module is used for error detection, error extraction and error correction. The voltage-controlled voltage generation module is used for voltage control, dynamic adjustment and improving system stability. The VCXO module is used to provide a stable frequency signal and frequency control. The feedback control module is used to maintain system stability, improve control accuracy, enhance system robustness, implement negative feedback and positive feedback, and achieve automatic correction. The signal acquisition module usually includes circuits such as amplifiers, filters, and analog-to-digital converters, which are used to enhance, filter, and digitize signals. The signal acquisition module is mainly responsible for signal reception and transmission, ensuring the integrity and accuracy of signals. The synchronous error extraction module can monitor the synchronous error between the received signal and the transmitted signal in real time. Through specific algorithms, such as the Gardner bit synchronization algorithm, the module can calculate the deviation between the received signal and the transmitted signal in terms of time or phase. After detecting the synchronous error, the synchronous error extraction module can extract the error signal from the received signal. By adjusting the output frequency or phase of the numerically controlled oscillator, the synchronous error between the received signal and the transmitted signal can be reduced, improving the performance of the communication system. The voltage-controlled voltage generation module can achieve precise control of the output voltage. By adjusting the magnitude of the control voltage, the value of the output voltage can be changed continuously and smoothly. It can quickly respond to changes in the external control voltage and achieve dynamic adjustment of the output voltage. The core function of the VCXO module is to provide a stable frequency signal. Utilizing the high stability characteristics of quartz crystals, it generates high-precision frequency signals. Through the control of an external voltage, the VCXO can finely adjust the output frequency within a certain range to meet the requirements of different applications. By introducing the VCXO module, electronic devices can achieve more precise frequency control and higher system performance.

[0028] The VCXO can ensure the synchronization and correctness between various parts, reducing time deviation and jitter problems. The feedback control module compares the output signal of the system with the desired signal, generates an error signal, and adjusts the input signal according to the error signal to keep the system stable near the desired output value. This mechanism can effectively cope with parameter changes within the system and external environmental disturbances, ensuring the stable operation of the system. By continuously measuring the output signal and comparing it with the desired signal, the feedback control module can adjust the input signal in real time, thereby reducing the output error of the system and improving control accuracy. The feedback control module has strong robustness against system parameter uncertainties and external disturbances. The feedback control module can automatically adjust the control input according to the error signal, making the system output quickly approach the desired value. In a control system, the feedback control module can implement two control modes: negative feedback and positive feedback. Negative feedback is used to stabilize the system output and reduce errors; while positive feedback is used to enhance the system output and improve the system's response speed. The feedback control module selects the appropriate feedback mode in different application scenarios.

[0029] In summary, the present application provides a method for adjusting the frequency of a voltage-controlled crystal oscillator based on public network signal scanning, which has the following beneficial effects:

[0030] 1. The method for adjusting the frequency of a voltage-controlled crystal oscillator based on public network signal scanning has extremely high synchronization accuracy and can precisely meet the strict requirements of air interface synchronization. In the field of public network signal acquisition and processing, the accuracy of air interface synchronization is a key factor to ensure the stability of data transmission and improve communication efficiency. This solution ensures a high degree of consistency between the local clock and the base station clock through an innovative synchronization mechanism, thereby effectively avoiding problems such as signal demodulation errors and reduced sampling efficiency caused by clock frequency offset;

[0031] 2. The method for adjusting the frequency of a voltage-controlled crystal oscillator based on public network signal scanning completely abandons the dependence on the GPS module while achieving high-precision synchronization. Traditional synchronization schemes often rely on GPS signals to obtain accurate clock information, which not only increases the hardware cost but also causes synchronization failure in indoor or blocked environments. Through circuit design and algorithm optimization, autonomous synchronization without a GPS module has been successfully achieved, greatly reducing the hardware cost of the device;

[0032] 3. Removing the GPS module in the method for adjusting the frequency of a voltage-controlled crystal oscillator based on public network signal scanning also brings significant advantages in terms of power consumption. The GPS module needs to continuously receive and process satellite signals during operation, which undoubtedly increases the energy consumption of the device. However, through an efficient synchronization algorithm and low-power circuit design in this technical solution, the power consumption of the device has been effectively controlled while maintaining high-precision synchronization. This not only extends the battery life of the device but also improves the overall energy efficiency of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a flowchart of the method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0035] The present application provides a technical solution. Please refer to Figure 1 , a method for adjusting the frequency of a voltage-controlled crystal oscillator based on public network signal scanning, including:

[0036] S1: Signal scanning

[0037] Using a scanning system to scan the public network frequency band, the RF front-end component has sufficient bandwidth to cover all or part of the public network frequency band, so as to be able to receive wireless signals from different frequency points. During the scanning process, the received wireless signals are preprocessed, including filtering, amplification, and analog-to-digital conversion, to extract the effective signal components that may contain the synchronization signal of the target base station. The preprocessed signals are analyzed to identify and capture the synchronization signal of the target base station.

[0038] S2: Signal capture

[0039] After successfully capturing the synchronization signal, calculate the peak value, which reflects the matching degree between the synchronization signal and the locally generated reference signal, and is used to evaluate the strength and reliability of the signal. Record and output the relevant peak value of the synchronization signal and its position information in the time domain and / or frequency domain, including the specific time point when the synchronization signal appears, the frequency offset, and the relative position relative to the scanning starting point, so as to provide detailed information about the status of the target base station.

[0040] S3: Voltage-controlled voltage generation

[0041] Extract the carrier frequency deviation from the processed digital baseband signal. The carrier frequency deviation represents the difference between the carrier frequency of the received signal and the reference carrier frequency generated by the local oscillator. Its extraction is for continuous monitoring and analysis of the signal phase change, calculate the frequency error of the local crystal oscillator, convert the deviation value into a percentage error or an absolute frequency deviation value relative to the nominal frequency of the local crystal oscillator, and output the frequency error information of the local crystal oscillator for subsequent calibration, compensation, and recording.

[0042] S4: Voltage-controlled voltage adjustment

[0043] Step S3: The PID controller, as the core control unit, is used to receive the input signal and process the signal according to the preset control algorithm. The PID controller comprehensively considers the current frequency error of the system, the cumulative amount of the frequency error, and the change rate of the frequency error, and generates a corresponding voltage-controlled voltage adjustment amount through precise calculation. This adjustment amount has high accuracy and stability, and can ensure the precise control of the system output frequency. The DAC module, as the digital-to-analog conversion unit, is connected to the PID controller. The DAC module converts the digital voltage-controlled voltage adjustment amount generated by the PID controller into an analog signal form for subsequent loading to the voltage-controlled terminal of the VCXO module. The DAC module has high precision and high stability, and can ensure the accuracy and reliability of the conversion process. The VCXO module, as the frequency output unit, has its voltage-controlled terminal connected to the output terminal of the DAC module. The VCXO module adjusts its output frequency according to the received analog voltage-controlled voltage adjustment amount. The VCXO module has a wide tuning range and good frequency stability, and can meet the precise requirements of the system for the output frequency. The input signal first enters the PID controller, and a voltage-controlled voltage adjustment amount is generated after processing; then, this adjustment amount is converted into an analog signal by the DAC module; finally, the analog signal is loaded to the voltage-controlled terminal of the VCXO module to adjust its output frequency.

[0044] S5: Closed-loop feedback and stability enhancement

[0045] Monitor the frequency convergence state after adjustment in real time. This module evaluates the stability and accuracy of the frequency by continuously sampling and analyzing the frequency data. If the monitored frequency convergence state exceeds the preset threshold range, that is, the frequency deviation reaches or exceeds the predetermined limit, the system will immediately identify and respond to this abnormal situation. When it is detected in real time that the frequency convergence state exceeds the threshold, the system will automatically trigger the resynchronization process. This process aims to recalibrate and adjust the system frequency to ensure that it is consistent with the target frequency. The resynchronization process includes re-initializing the PID controller parameters, recalibrating the DAC module output, or making necessary adjustments to the VCXO module to quickly restore the frequency stability and accuracy of the system. During the operation of the system, if a signal loss or transmission interruption occurs, the system will automatically enable the hold mode. The hold mode is an emergency handling mechanism used to maintain the short-term stability of the system during signal loss. In the hold mode, the system will use historical data or preset backup parameters to continue to control the VCXO module, thereby ensuring that the output frequency will not drift or fluctuate significantly before the signal is restored.

[0046] S6: Frequency protection

[0047] The turned-on electromagnetic field shielding device can not only effectively block external electromagnetic noise and interference signals, but also suppress the electromagnetic radiation generated inside the system, thus ensuring that the frequency signals inside the system remain pure and stable. This comprehensive protection mechanism enables the system to maintain high-performance frequency output in a complex electromagnetic environment. According to different application scenarios and frequency protection requirements, the structure, material or opening degree of the shielding device can be adjusted to achieve the best shielding effect.

[0048] Step S1: The synchronization signal includes the primary synchronization signal, the secondary synchronization signal, and the signal pattern for base station identification and time synchronization. The primary synchronization signal is also used to achieve coarse time synchronization between the UE and the base station, laying the foundation for subsequent processes such as fine synchronization and channel estimation. The secondary synchronization signal is used in conjunction with the primary synchronization signal to achieve precise synchronization between the UE and the base station. After capturing the primary synchronization signal, the UE will further search for the secondary synchronization signal to improve the signal accuracy, help the UE accurately identify the base station, and achieve precise time synchronization with the base station.

[0049] Step S3: The information is represented in digital form, including the timestamp, the deviation type, and the specific error value. The frequency information represented in digital form can achieve higher accuracy and stability. The development of digital signal processing technology has made it possible to precisely control the frequency. Through digital algorithms, the frequency can be finely tuned to meet extremely high accuracy requirements. In communication, measurement, and control systems, a high-precision frequency source is crucial for ensuring signal synchronization, improving the reliability and accuracy of data transmission. The voltage-controlled crystal oscillator can stably output a frequency signal that meets the requirements through digital control, enabling the voltage-controlled crystal oscillator to easily communicate with other digital devices and achieve automated control. The digitally controlled voltage-controlled crystal oscillator can be easily integrated into various digital systems to improve the overall performance and reliability of the system.

[0050] Step S6: The electromagnetic field shielding device includes a metal shielding cover configured outside the crystal oscillator. The metal shielding cover can ensure the accuracy of the crystal oscillator's output frequency, thus ensuring the correct execution of the system's timing logic, reducing data transmission errors or losses caused by unstable crystal oscillator frequencies, and improving the communication performance of the system.

[0051] Step S4: The PID controller is used to maintain the stable state of the controlled object, improve the control accuracy of the system, realize the automatic control and response speed of complex process parameters, and adjust the output of the controller according to the magnitude of the current error. When the error is large, the output signal is also large, thus accelerating the response speed of the controlled object. Proportional control can make the system quickly approach the set value and adjust the output of the controller according to the amount of error accumulated over time. Eliminate the steady-state error of the system and ensure that the system finally stabilizes near the set value. The role of integral control is similar to accumulating errors and continuously adjusting the output, and adjusts the output of the controller according to the rate of change of the error. Predict the future state change trend of the system, thereby reducing overshoot and improving the stability of the system. The introduction of derivative control can suppress the oscillation of the system and is adjusted according to the input and output data of the system, so it has strong adaptability and flexibility.

[0052] Step S4: The DAC module is a digital-to-analog converter, which is used to process the input digital signal, including filtering, amplification and digital signal processing algorithms, and is responsible for processing the input digital signal, such as filtering, amplification, digital signal processing algorithms, converting the digital signal into an analog signal, generating the corresponding analog voltage or current according to the input digital code, and is responsible for filtering, amplifying and other processing of the output analog signal to ensure the quality and stability of the signal.

[0053] Step S5: Hold mode: The system calculates the drift of the crystal oscillator output frequency using the previously collected data and model parameters, and performs self-correction compensation. Using the frequency drift model trained with the historical data accumulated in the locked state, predicts the change trend of the frequency output, and compensates the actual output frequency with the predicted value, thereby maintaining the accuracy of the frequency.

[0054] Step S5: The voltage-controlled voltage adjustment includes a pre-adjustment circuit, and adjusts the capacitance component, adjusts the current near the crystal and temperature compensation according to the system settings when the signal is lost, and automatically adjusts the parameters of the device through the pre-adjustment circuit, thereby greatly improving the overall automation of the device.

[0055] The scanning system includes a signal acquisition module, a synchronization error extraction module, a voltage-controlled voltage generation module, a VCXO module and a feedback control module, and scans the public network frequency band through the scanning system.

[0056] The signal acquisition module is used for data acquisition functions and signal conditioning and conversion. The synchronous error extraction module is used for error detection, error extraction, and error correction. The voltage-controlled voltage generation module is used for voltage control, dynamic adjustment, and improving system stability. The VCXO module is used to provide a stable frequency signal and frequency control. The feedback control module is used to maintain system stability, improve control accuracy, enhance system robustness, implement negative and positive feedback, and achieve automatic correction. The signal acquisition module usually includes circuits such as amplifiers, filters, and analog-to-digital converters, which are used to enhance, filter, and digitize signals. The signal acquisition module is mainly responsible for signal reception and transmission, ensuring signal integrity and accuracy. The synchronous error extraction module can real-time monitor the synchronous error between the received signal and the transmitted signal. Through specific algorithms, such as the Gardner bit synchronization algorithm, the module can calculate the deviation in time or phase between the received signal and the transmitted signal. After detecting the synchronous error, the synchronous error extraction module can extract the error signal from the received signal. By adjusting the output frequency or phase of the numerically controlled oscillator, the synchronous error between the received signal and the transmitted signal can be reduced, improving the performance of the communication system. The voltage-controlled voltage generation module can achieve precise control of the output voltage. By adjusting the magnitude of the control voltage, the value of the output voltage can be continuously and smoothly changed. It can quickly respond to changes in the external control voltage, realizing dynamic adjustment of the output voltage. The core function of the VCXO module is to provide a stable frequency signal. Utilizing the high stability characteristics of the quartz crystal, it generates a high-precision frequency signal. Through the control of the external voltage, the VCXO can fine-tune the output frequency within a certain range to meet the requirements of different applications. By introducing the VCXO module, electronic devices can achieve more precise frequency control and higher system performance.

[0057] The VCXO can ensure the synchronization and correctness between various parts, reducing time deviation and jitter problems. The feedback control module compares the output signal of the system with the desired signal, generates an error signal, and adjusts the input signal according to the error signal, making the system stable near the desired output value. This mechanism can effectively cope with parameter changes within the system and external environmental disturbances, ensuring the stable operation of the system. By continuously measuring the output signal and comparing it with the desired signal, the feedback control module can real-time adjust the input signal, thereby reducing the output error of the system and improving control accuracy. The feedback control module has strong robustness against system parameter uncertainties and external disturbances. The feedback control module can automatically adjust the control input according to the error signal, making the system output quickly approach the desired value. In a control system, the feedback control module can implement two control modes: negative feedback and positive feedback. Negative feedback is used to stabilize the system output and reduce errors; while positive feedback is used to enhance the system output and improve the system's response speed. The feedback control module selects the appropriate feedback mode in different application scenarios.

[0058] Extremely high synchronization accuracy, which can precisely meet the strict requirements of air interface synchronization. In the field of public network signal acquisition and processing, the accuracy of air interface synchronization is a key factor in ensuring data transmission stability and improving communication efficiency. This solution ensures a high degree of consistency between the local clock and the base station clock through an innovative synchronization mechanism, thus effectively avoiding problems such as signal demodulation errors and reduced sampling efficiency caused by clock frequency offset;

[0059] While achieving high-precision synchronization, it completely abandons the dependence on GPS modules. Traditional synchronization solutions often rely on GPS signals to obtain accurate clock information, which not only increases the hardware cost but also causes synchronization failure in indoor or blocked environments. This solution has successfully achieved autonomous synchronization without a GPS module through ingenious circuit design and algorithm optimization, greatly reducing the hardware cost of the device;

[0060] Removing the GPS module also brings significant advantages in terms of power consumption. The GPS module needs to continuously receive and process satellite signals during operation, which undoubtedly increases the energy consumption of the device. This technical solution effectively controls the power consumption of the device while maintaining high-precision synchronization through an efficient synchronization algorithm and low-power circuit design. This not only extends the battery life of the device but also improves the overall energy efficiency of the device.

[0061] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0062] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for adjusting the frequency of a voltage-controlled crystal oscillator based on public network signal scanning, characterized in that: Including: S1: Signal Scanning Using a scanning system, scan the public network frequency band. Cover all or part of the range of the public network frequency band through the RF front-end component, receive wireless signals from different frequency points. During the scanning process, preprocess the received wireless signals, including filtering, amplification, and analog-to-digital conversion, extract the effective signal components containing the target base station synchronization signal, analyze the preprocessed signals, and identify and capture the synchronization signal of the target base station; S2: Signal Capture After successfully capturing the synchronization signal, calculate the peak value. The peak value reflects the matching degree between the synchronization signal and the locally generated reference signal, evaluate the signal strength and reliability, record and output the relevant peak value of the synchronization signal and its position information in the time domain and frequency domain, including the specific time point when the synchronization signal appears, the frequency offset, and the relative position relative to the scanning start point, providing detailed information about the target base station status; S3: Voltage-Controlled Voltage Generation Extract the carrier frequency deviation from the processed digital baseband signal. The carrier frequency deviation represents the difference between the carrier frequency of the received signal and the reference carrier frequency generated by the local oscillator. Its extraction is based on the continuous monitoring and analysis of the signal phase change, calculate the frequency error of the local crystal oscillator, convert the deviation value into a percentage error or an absolute frequency deviation value relative to the nominal frequency of the local crystal oscillator, and output the frequency error information of the local crystal oscillator for subsequent calibration, compensation, and recording; S4: Voltage-Controlled Voltage Adjustment Input the information value obtained in step S3 into the PID controller to generate a voltage-controlled voltage adjustment amount, and load the value to the voltage-controlled terminal of the VCXO module through the DAC module to adjust the output frequency; S5: Closed-Loop Feedback and Stability Enhancement Real-time monitor the frequency convergence state after adjustment. If it exceeds the threshold, trigger the resynchronization process; when the signal is lost, enable the hold mode to maintain historical data and maintain short-term stability; S6: Frequency Protection Turn on the electromagnetic field shielding device for frequency protection; In the step S1, the synchronization signal includes the primary synchronization signal, the secondary synchronization signal, and the signal pattern for base station identification and time synchronization; In the step S3, the information is represented in digital form, including the time stamp, the deviation type, and the error value; In the step S6, the electromagnetic field shielding device includes a metal shielding cover configured outside the crystal oscillator; In the step S4, the DAC module is a digital-to-analog converter, which is used to process the input digital signal, including filtering, amplification, and digital signal processing algorithms; The scanning system includes a signal acquisition module, a synchronization error extraction module, a voltage-controlled voltage generation module, a VCXO module, and a feedback control module.

2. The voltage-controlled crystal oscillator frequency adjustment method based on public network signal scanning according to claim 1, characterized in that: In the step S4, the PID controller is used to maintain the stability of the controlled object, improve the control accuracy of the system, realize the automatic control and response speed of complex process parameters.

3. The voltage-controlled crystal oscillator frequency adjustment method based on public network signal scanning according to claim 1, wherein: In the step S5, the hold mode is that the system calculates the drift amount of the crystal oscillator output frequency using the previously collected data and model parameters, and performs self-correction compensation.

4. The voltage-controlled crystal oscillator frequency adjustment method based on public network signal scanning according to claim 1, wherein: In the step S5, the voltage-controlled voltage adjustment includes a pre-adjustment circuit, and when a signal is lost, the capacitance component is adjusted, the current near the crystal is adjusted, and temperature compensation is performed according to the system settings.

5. The voltage-controlled crystal oscillator frequency adjustment method based on public network signal scanning according to claim 1, characterized in that: The signal acquisition module is used for data acquisition functions and signal conditioning and conversion. The synchronous error extraction module is used for error detection, error extraction, and error correction. The voltage-controlled voltage generation module is used for voltage control, dynamic adjustment, and improving system stability. The VCXO module is used to provide a stable frequency signal and frequency control. The feedback control module is used to maintain system stability, improve control accuracy, enhance system robustness, implement negative feedback and positive feedback, and achieve automatic correction.

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