Microwave cavity filter system with automatic tuning function

Abstract

The present application discloses a microwave cavity filter system with automatic tuning function, which relates to the field of cavity filters and realizes adaptive control of signal frequency fluctuations through multi-level tuning strategies. The system includes a detection module, a control module, and first, second and third tuning units. The detection module monitors the quality indicators such as frequency fluctuation and signal-to-noise ratio of the signal in real time and generates fluctuation information; the control module selects the corresponding tuning unit according to the fluctuation amplitude based on the fluctuation information. The first tuning unit performs a small compensation, and the second tuning unit expands the bandwidth to accommodate medium fluctuations; when the signal frequency deviation trend is obvious or the signal-to-noise ratio is lower than the threshold, the system uses the third tuning unit to synchronously adjust the center frequency and bandwidth and reset the frequency range. In addition, the system sets the tuning parameters in advance through trend prediction, and dynamically monitors the signal-to-noise ratio during the bandwidth adjustment process, and gradually shrinks the bandwidth to ensure signal quality.

Description

Technical Field

[0001] The present application relates to the field of cavity filters, and in particular to a microwave cavity filter system with an automatic tuning function. Background Art

[0002] Automatic tuning filters can adapt to the frequency fluctuations of input signals in real time, ensuring that the signal maintains stable and pure output characteristics in complex environments. Traditional microwave filters mostly use manual adjustment methods to meet different frequency requirements by replacing filter components or manually adjusting the cavity structure. However, this method is difficult to adapt to rapidly changing frequency requirements, the operation is cumbersome and the accuracy is limited. Therefore, automatic tuning technology plays an increasingly important role in modern microwave filtering systems.

[0003] For example, the Chinese patent with the authorization announcement number CN104659460B discloses an automatic tuning method and system for microwave cavity filters. The system mainly relies on a mechanical actuator to change the resonant frequency of the filter by adjusting the height of the tuning rod inside the cavity filter. In order to achieve precise tuning, the patent uses a particle optimization algorithm to optimize the tuning parameters so that the actual filter waveform is close to the target waveform. The system ensures that the output signal of the filter meets the preset frequency characteristics through step-by-step adjustment and feedback iterative optimization. In addition, the technical solution introduces a monitoring feedback mechanism in the automated tuning process to monitor the tuning effect in real time and adjust the position of the mechanical actuator.

[0004] However, the above technical solution still has some shortcomings. For example, this method mainly relies on mechanical adjustment for tuning, which has a slow adjustment speed and is difficult to cope with frequency fluctuations in a high dynamic environment. At the same time, the mechanical execution structure is easily affected by environmental factors, which may lead to a decrease in tuning accuracy and stability. The feedback optimization of this method relies on the particle optimization algorithm, which may converge slowly under complex signal conditions, thus affecting the tuning efficiency. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present application discloses a microwave cavity filter system with automatic tuning function, which comprises:

[0006] A detection module, used for detecting frequency fluctuation of an input signal and generating fluctuation information;

[0007] A control module, configured to determine a frequency interval adjustment requirement based on a relationship between the fluctuation information and a current frequency interval of the microwave cavity filter, and generate adjustment information; and dynamically adjust the frequency interval of the microwave cavity filter based on the adjustment information;

[0008] The dynamic adjustment includes: in response to the fluctuation amplitude in the fluctuation information being less than a first threshold, adjusting the current frequency interval by using the first tuning unit through compensation adjustment; wherein the first threshold is determined based on the compensation capability of the first tuning unit;

[0009] In response to the fluctuation amplitude in the fluctuation information being greater than or equal to a first threshold and less than a second threshold, adjusting the current frequency interval by using the second tuning unit through bandwidth adjustment; wherein the second threshold is determined based on the bandwidth adjustment capability of the second tuning unit and the compensation capability of the first tuning unit;

[0010] In response to the fluctuation amplitude in the fluctuation information being greater than or equal to the second threshold, or the fluctuation information containing trend information, the third tuning unit is used to reset the frequency interval based on the fluctuation information by adjusting the center frequency and the bandwidth.

[0011] As an optional implementation manner, the first tuning unit is used to:

[0012] The center frequency of the current frequency interval is not adjusted, and the upper boundary or the lower boundary of the current frequency interval is adjusted by changing the value of the variable capacitor or the adjustable inductor in the microwave cavity filter.

[0013] As an optional implementation, the second tuning unit is used to: not adjust the center frequency of the current frequency interval, and expand the bandwidth of the current frequency interval through the adjustable bandwidth element in the microwave cavity filter.

[0014] As an optional implementation manner, the dynamic adjustment further includes:

[0015] Performing a first boundary detection on the fluctuation information to determine whether there is trend information in the fluctuation information;

[0016] The first boundary detection includes: performing trend analysis on the fluctuation information based on historical power spectrum density information of the input signal to determine the direction and rate of continuous change of the frequency of the input signal;

[0017] Based on the continuous change direction and rate of the frequency of the input signal, the change of the frequency of the input signal in a future preset time period is determined; in response to the frequency of the input signal exceeding the current frequency range in a future preset time period, it is determined that there is trend information in the fluctuation information.

[0018] As an optional implementation manner, resetting the frequency interval based on the trend information by adjusting the center frequency and the bandwidth includes:

[0019] Determine the target center frequency of the microwave cavity filter based on the frequency change direction and rate of the input signal in the trend information; wherein the target center frequency is determined based on the offset between the center frequency of the current frequency interval and the frequency change trend;

[0020] Determining a target bandwidth of the microwave cavity filter based on a frequency variation range of the input signal;

[0021] Based on the trend information, a time point when the input signal exceeds the current frequency range is determined, and before the time point, the current center frequency is adjusted to the target center frequency, and at the same time, the current bandwidth is adjusted to the target bandwidth to form a new frequency range.

[0022] As an optional implementation manner, the bandwidth adjustment further includes:

[0023] When performing bandwidth adjustment, detecting a quality indicator of the input signal; wherein the quality indicator includes: a signal-to-noise ratio;

[0024] In response to the signal-to-noise ratio of the input signal being less than an acceptable threshold, the frequency interval is reset by adjusting the center frequency and the bandwidth using the third tuning unit.

[0025] As an optional implementation manner, in response to the signal-to-noise ratio of the input signal being less than an acceptable threshold, resetting the frequency interval by adjusting the center frequency and the bandwidth using the third tuning unit includes:

[0026] Based on the quality index of the input signal, determining the rate of decrease of the signal-to-noise ratio, and based on the partial proportional relationship between the rate of decrease and the center frequency of the current frequency interval, setting the target center frequency of the microwave cavity filter; the bandwidth remains unchanged in this process;

[0027] In response to the target center frequency being set, the quality index of the input signal is detected, and based on the change of the signal-to-noise ratio, the bandwidth of the microwave cavity filter is gradually reduced until the signal-to-noise ratio is restored to above the acceptable threshold.

[0028] As an optional implementation manner, setting the target center frequency of the microwave cavity filter includes:

[0029] Based on the decrease rate of the signal-to-noise ratio, the current center frequency is offset according to a preset proportional relationship to set a target center frequency of the microwave cavity filter, where the target center frequency is equal to the current center frequency plus the decrease rate multiplied by a preset proportional coefficient.

[0030] As an optional implementation manner, the step of gradually reducing the bandwidth of the microwave cavity filter includes:

[0031] Based on the increment of signal-to-noise ratio recovery, the bandwidth of the microwave cavity filter is gradually reduced based on a preset bandwidth reduction ratio.

[0032] Compared with the prior art, the invention has the following beneficial effects: by combining passive tuning, bandwidth adjustment and active tuning, a multi-level tuning strategy is constructed, so that the system can complete compensation through passive tuning when the frequency fluctuation amplitude is small, automatically expand the bandwidth when the fluctuation exceeds the passive tuning range, and when the frequency deviation trend is obvious, the center frequency and bandwidth are reset to ensure that the filter always adapts to the signal changes. This multi-level strategy significantly improves the frequency response capability and adaptability of the system in a complex signal environment.

[0033] By predicting the direction and rate of change of the signal frequency through trend analysis, adjustments can be made before the signal frequency offset exceeds the current frequency range. By judging trend information through real-time boundary detection, the center frequency and bandwidth are adjusted synchronously in advance to ensure that the frequency range always covers the change range of the input signal. This design of advance prediction and adjustment reduces the lag of resetting the frequency range, allowing the system to maintain stable signal output in the frequency change trend.

[0034] In the process of improving signal quality, the present invention adopts a gradual bandwidth reduction strategy, so that the system can gradually reduce the bandwidth in proportion during the process of signal-to-noise ratio recovery, avoid signal distortion caused by sudden bandwidth reduction, and finally adjust the frequency range to the optimal range. This gradual adjustment method balances signal quality and bandwidth adjustment speed, ensuring signal stability and filter selectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of a microwave cavity filter system with automatic tuning function provided in an embodiment of the present application;

[0036] Figure 2 A flow chart of a method for dynamic adjustment provided in an embodiment of the present application;

[0037] Figure 3 A flow chart of a method for resetting frequency intervals provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0039] Figure 1 This is a schematic diagram of a microwave cavity filter system with an automatic tuning function provided in an embodiment of the present application. The system includes: a detection module 10 and a control module 20, wherein:

[0040] The detection module 10 is used to detect the frequency fluctuation of the input signal and generate fluctuation information;

[0041] The control module 20 is used to determine the frequency interval adjustment requirement and generate adjustment information based on the relationship between the fluctuation information and the current frequency interval of the microwave cavity filter; and dynamically adjust the frequency interval of the microwave cavity filter based on the adjustment information.

[0042] Figure 2 This is a flow chart of a method for dynamic adjustment provided in an embodiment of the present application, wherein the dynamic adjustment includes steps S101 to S103, wherein:

[0043] S101: In response to the fluctuation amplitude in the fluctuation information being less than a first threshold, adjusting the current frequency interval by using a first tuning unit through compensation adjustment; wherein the first threshold is determined based on the compensation capability of the first tuning unit;

[0044] S102: In response to the fluctuation amplitude in the fluctuation information being greater than or equal to a first threshold and less than a second threshold, adjusting the current frequency interval by using a second tuning unit through bandwidth adjustment; wherein the second threshold is determined based on a bandwidth adjustment capability of the second tuning unit and a compensation capability of the first tuning unit;

[0045] S103: In response to the fluctuation amplitude in the fluctuation information being greater than or equal to a second threshold, or the fluctuation information containing trend information, resetting the frequency interval by adjusting the center frequency and the bandwidth based on the fluctuation information using a third tuning unit.

[0046] The present application adapts to the frequency fluctuation of the input signal through dynamic tuning, and is particularly suitable for application environments with unstable signal frequencies, such as mobile communications and radar systems.

[0047] The microwave cavity filter system includes a detection module 10, a control module 20, and a plurality of tuning units (a first tuning unit, a second tuning unit, and a third tuning unit). The detection module 10 is used to detect the frequency fluctuation of the input signal and generate fluctuation information. The fluctuation information includes the real-time frequency value of the input signal and its change amplitude, change trend, etc., which are used for subsequent tuning decisions. The input signal can be a dynamic signal from an external microwave source, and the detection module 10 obtains the fluctuation information by monitoring the real-time change of the signal frequency.

[0048] The control module 20 is used to determine the frequency interval adjustment requirement based on the relationship between the fluctuation information and the current frequency interval of the microwave cavity filter, and generate adjustment information. The control module 20 receives the fluctuation information output by the detection module 10, calculates the deviation between the fluctuation information and the current frequency interval, determines whether the frequency interval needs to be adjusted based on the deviation, and determines the required adjustment type and range.

[0049] The detection module 10 may include a frequency detection circuit or a phase detection circuit, whose input end receives an input signal from a microwave signal source, and generates fluctuation information reflecting the frequency characteristics of the signal by measuring the change amount and direction of the signal frequency. The output of the fluctuation information is transmitted to the control module 20 for subsequent tuning judgment.

[0050] In a specific implementation, the first threshold is used to distinguish between small fluctuations that can be compensated by the first tuning unit and medium fluctuations that require bandwidth adjustment. The first threshold is set according to the compensation capability of the first tuning unit, that is, the frequency adjustment range that the first tuning unit can achieve by adjusting the variable capacitor or adjustable inductor in the microwave cavity filter.

[0051] For example, if the adjustable frequency range of the first tuning unit is ±0.5 MHz, the first threshold is set to within ±0.5 MHz. That is, when the fluctuation information shows that the frequency deviation is within ±0.5 MHz, the system starts the compensation adjustment of the first tuning unit; if it exceeds ±0.5 MHz, the second tuning unit is entered to adjust the bandwidth.

[0052] In a specific implementation, the second threshold is used to distinguish between medium-amplitude fluctuations and large-amplitude fluctuations, and calibrates the bandwidth adjustment range of the second tuning unit. When the frequency fluctuation amplitude is greater than or equal to the second threshold, or frequency trend information appears, the third tuning unit is triggered to reset the center frequency and bandwidth. The second threshold is set based on the bandwidth adjustment capability of the second tuning unit. Specifically, the control module 20 uses the bandwidth increment that can be achieved by the second tuning unit as the threshold boundary, and sets the second threshold to ensure that the bandwidth adjustment can cover the frequency offset within the fluctuation range.

[0053] For example, assuming that the bandwidth range that the second tuning unit can expand is ±1.5 MHz to ±5 MHz, the second threshold is set to between 1.5 MHz and 5 MHz. That is, when the amplitude of the frequency fluctuation information is greater than ±0.5 MHz but less than 5 MHz, the system triggers the second tuning unit to expand the bandwidth; if the fluctuation amplitude is greater than 5 MHz, or a frequency trend is detected, the third tuning unit is triggered.

[0054] In a specific implementation, the above dynamic adjustment can be regarded as a compensation adjustment for small fluctuations, a bandwidth adjustment for medium fluctuations, and a resetting of the frequency interval.

[0055] The first tuning unit adjusts the value of the variable capacitor or adjustable inductor in the microwave cavity filter according to the instruction of the control module 20 to fine-tune the upper boundary or lower boundary of the current frequency interval to compensate for small fluctuations. For example, the first tuning unit can use a step capacitor or a small range adjustable inductor to control the change of the capacitance value or the inductance value to adjust the frequency interval boundary.

[0056] The second tuning unit receives the adjustment information and expands the frequency range by increasing or decreasing the capacitance or inductance value of the bandwidth element to cover a larger frequency fluctuation. For example, bandwidth expansion can be achieved by adding a variable capacitor network to adapt to frequency fluctuations. Assuming that the current bandwidth is 2 MHz, the bandwidth is expanded to 5 MHz to cover a larger range of frequency fluctuations. Capacitors can be connected in parallel in the circuit or variable inductors can be used to adjust the bandwidth to the target range.

[0057] The third tuning unit synchronously adjusts the center frequency and bandwidth according to the adjustment information so that the frequency interval covers the new signal frequency range. For example, when there is trend information (such as continuous rise or fall) in the signal frequency fluctuation or exceeds the 5 MHz range, the system adjusts the center frequency. Assuming that the signal frequency continues to rise to 10 MHz, the third tuning unit adjusts the center frequency to 10 MHz, and the bandwidth is synchronously expanded to meet the new signal range. Bandwidth adjustment can be achieved by adjusting the capacitance and inductance in the cavity to ensure that the new frequency interval covers all trend frequency changes.

[0058] As an optional implementation manner, the first tuning unit is used to:

[0059] The center frequency of the current frequency interval is not adjusted, and the upper boundary or the lower boundary of the current frequency interval is adjusted by changing the value of the variable capacitor or the adjustable inductor in the microwave cavity filter.

[0060] The first tuning unit is designed to achieve compensatory tuning under small frequency fluctuation conditions to ensure that the system maintains the stability of the frequency range without changing the center frequency. The first tuning unit adjusts the value of the variable capacitor or adjustable inductor in the microwave cavity to achieve the purpose of adjusting the upper or lower boundary of the current frequency range.

[0061] In a specific implementation, the first tuning unit includes at least one variable capacitor, and fine adjustment of the upper boundary or the lower boundary of the frequency range is achieved by adjusting the capacitance value. The structure of the variable capacitor may include an electronically adjustable capacitor (such as a varactor diode) or a mechanically adjustable capacitor, and its capacitance value is controlled by adjusting the input voltage or manually adjusting the capacitor position.

[0062] In addition to the variable capacitor, the first tuning unit also includes an adjustable inductor for fine-tuning the frequency boundary by adjusting the inductance value. The adjustable inductor can adopt a sliding inductor or a controllable inductor device (such as a core displacement adjustable inductor) to adjust the inductance value by changing the core position or the number of turns of the coil.

[0063] In a specific implementation, the design principle of the first tuning unit is to maintain the center frequency of the frequency interval unchanged and only fine-tune the boundary of the frequency interval. The control module 20 transmits the signal with a fluctuation amplitude within the first threshold to the first tuning unit according to the fluctuation information of the detection module 10, so that the upper boundary or the lower boundary is adjusted without affecting the center frequency to achieve compensation for small fluctuations.

[0064] When the frequency fluctuation tends to approach the upper boundary of the current frequency interval, the control module 20 instructs the first tuning unit to increase the upper boundary of the frequency interval by appropriately reducing the capacitance value of the variable capacitor or increasing the inductance value of the adjustable inductor. When the capacitance value of the variable capacitor decreases, the resonant frequency of the microwave cavity increases, so that the upper boundary is adjusted toward a higher frequency, thereby increasing the height range of the frequency interval.

[0065] When the fluctuation tends to approach the lower boundary of the current frequency range, the first tuning unit can reduce the lower boundary of the frequency range by appropriately increasing the capacitance value of the variable capacitor or reducing the inductance value of the adjustable inductor. When the capacitance value of the variable capacitor increases, the resonant frequency decreases accordingly, so that the lower boundary expands toward a lower frequency direction, thereby improving the low-end tolerance of the frequency range.

[0066] In this way, the first tuning unit of the present invention achieves flexible adjustment of the frequency boundary by fine-tuning the variable capacitor and the adjustable inductor without changing the center frequency. This design reduces unnecessary bandwidth adjustment when the frequency fluctuation is small, improves the response speed and stability of the system, and is suitable for working environments with small signal frequency deviation amplitude.

[0067] As an optional implementation, the second tuning unit is used to: not adjust the center frequency of the current frequency interval, and expand the bandwidth of the current frequency interval through the adjustable bandwidth element in the microwave cavity filter.

[0068] The microwave cavity filter system of the present invention includes a second tuning unit, which is used to expand the bandwidth to cover a wider frequency range when the input signal frequency fluctuates greatly, so as to prevent the signal frequency from exceeding the working range of the filter. The tuning unit does not change the center frequency of the current frequency range during the bandwidth expansion process, ensuring that the system can still provide effective signal filtering under large frequency offsets.

[0069] The second tuning unit includes an adjustable capacitor network for adjusting the bandwidth range of the filter. The capacitor network includes multiple variable capacitor devices (such as a varactor diode array), and the total capacitance value can be adjusted in parallel or in series. By changing the capacitance value of the capacitor network, the tuning unit can increase or decrease the bandwidth of the filter, so that the upper and lower boundaries of the frequency range are expanded outward while the center frequency remains unchanged.

[0070] The second tuning unit also includes an adjustable inductor element for assisting bandwidth adjustment. The inductor element can increase or decrease the inductance value by changing the number of coil turns or adjusting the position of the magnetic core. The adjustment of the inductance value is used in conjunction with the adjustment of the capacitor network to match the frequency selectivity and bandwidth expansion of the filter to improve the broadband response capability of the filter.

[0071] In a specific implementation, the design principle of the second tuning unit is to expand the bandwidth through an adjustable bandwidth element while keeping the center frequency of the current frequency interval unchanged. The expansion of the bandwidth enables the frequency interval to cover a larger frequency offset range.

[0072] When the control module 20 detects that the frequency deviation of the input signal exceeds the compensation range of the first tuning unit but is still within the acceptable bandwidth range (ie, between the first threshold and the second threshold), the control module 20 sends a bandwidth extension instruction to the second tuning unit.

[0073] When the frequency fluctuation is biased toward the lower boundary of the frequency interval, the control module 20 instructs the second tuning unit to expand the bandwidth by increasing the total capacitance value of the capacitor network. After the capacitance value increases, the lower boundary of the frequency interval expands to a lower frequency, increasing the bandwidth range.

[0074] When the frequency fluctuation is biased toward the upper boundary of the frequency interval, the second tuning unit reduces the inductance value, thereby increasing the frequency of the upper boundary, so that the bandwidth of the frequency interval is expanded upward.

[0075] When the fluctuation is more severe and includes upper and lower boundary bidirectional fluctuations, the second tuning unit simultaneously adjusts the values ​​of the capacitor network and the inductor element to bidirectionally expand the bandwidth while keeping the current center frequency unchanged.

[0076] In this way, the second tuning unit of the present invention achieves the expansion of the frequency interval bandwidth through the adjustable bandwidth element while keeping the center frequency unchanged. This design provides effective bandwidth expansion tuning when the signal frequency deviation amplitude is large but still within the bandwidth tolerance range, avoids frequent center frequency adjustment, and improves the signal stability of the system within the medium fluctuation range.

[0077] As an optional implementation manner, the dynamic adjustment further includes:

[0078] Performing a first boundary detection on the fluctuation information to determine whether there is trend information in the fluctuation information;

[0079] The first boundary detection includes: performing trend analysis on the fluctuation information based on historical power spectrum density information of the input signal to determine the direction and rate of continuous change of the frequency of the input signal;

[0080] Based on the continuous change direction and rate of the frequency of the input signal, the change of the frequency of the input signal in a future preset time period is determined; in response to the frequency of the input signal exceeding the current frequency range in a future preset time period, it is determined that there is trend information in the fluctuation information.

[0081] In order to identify the trend change of the signal frequency in advance, the detection module 10 is used to analyze the fluctuation information of the input signal to determine whether there is trend information. The trend information is used to identify the continuous deviation direction and change rate of the input signal frequency, providing a basis for the system to actively tune and ensure that the system is adjusted in time before the frequency deviation exceeds the current frequency range.

[0082] Power spectral density (PSD) is used to describe the power distribution of a signal at different frequencies, and can reflect the frequency fluctuation characteristics of the input signal. The detection module 10 obtains the PSD data of the input signal in real time through a spectrum analyzer or a digital signal processing (DSP) chip. The system stores the real-time PSD data in the historical data buffer in each sampling period to facilitate subsequent trend analysis. The stored PSD data includes the frequency power distribution at multiple time points in the past, forming the historical spectrum information of the input signal.

[0083] In a specific implementation, a moving average algorithm, linear regression or other trend recognition algorithm can be used to analyze the historical PSD data to determine the changing trend of the signal frequency. For example, by calculating the moving average of the historical data to smooth the frequency change, it is possible to identify whether the frequency has a continuous upward or downward trend. For another example, a linear regression calculation is performed using the frequency data over a period of time to obtain the slope of the frequency change over time. The positive or negative slope indicates the direction of the frequency change, and the absolute value of the slope reflects the rate of change.

[0084] The slope obtained in the trend analysis indicates the direction of frequency change. When the slope is positive, it indicates that the frequency is increasing; when the slope is negative, it indicates that the frequency is decreasing. The absolute value of the slope or the slope of the moving average trend indicates the rate of frequency change, which is used to estimate the deviation amplitude of the signal in the future.

[0085] The system predicts the frequency change of the input signal within a preset time period in the future based on the direction and rate of frequency change.

[0086] Exemplarily, the system uses the current frequency value as a basis, and estimates the frequency change amount in the future time period according to the frequency change direction (increase or decrease) and rate. The calculation of the future frequency value is based on the following steps: if the trend analysis shows that the frequency is increasing, then the change rate is multiplied by the estimated amount of the future time period on the basis of the current frequency; if the trend analysis shows that the frequency is decreasing, then the change rate is multiplied by the estimated amount of the future time period on the basis of the current frequency. The predicted future frequency value is compared with the upper and lower boundaries of the current frequency interval to determine whether the frequency is about to exceed the current frequency interval range.

[0087] If the predicted future frequency value exceeds the upper boundary or the lower boundary of the current frequency interval, the system determines that there is trend information in the fluctuation information. Once the trend information is detected, the control module 20 generates a trend trigger signal to start the third tuning unit to reset the center frequency and bandwidth of the frequency interval so that the filter can adapt to the upcoming frequency change.

[0088] In this way, the detection module 10 of the present invention can identify the frequency change trend in advance through the analysis of the historical power spectrum density, so that the system can take tuning measures in advance when the frequency deviation trend appears, avoiding signal loss when the input signal frequency exceeds the current frequency range. This trend detection mechanism improves the filter's adaptive ability and ensures that the system always provides high-quality frequency response in a dynamic signal environment.

[0089] In addition, trend analysis can be combined with machine learning models. For example, historical power spectral density information can be trained using models suitable for time series prediction, such as long short-term memory networks (LSTM) or recurrent neural networks (RNN). These models can predict future frequency change trends by identifying long-term patterns of frequency fluctuations. In addition, machine learning methods based on anomaly detection (such as isolation forests or support vector machines) can also be used to detect sudden trends in signal frequencies, further improving the accuracy of trend information judgment, so that the system can make tuning decisions more timely.

[0090] It is understandable that the introduction of the above-mentioned machine learning model will also increase the complexity and computational burden of the system. In the specific implementation, it can be selected according to the system usage scenario.

[0091] As an alternative implementation, see Figure 3 , Figure 3 A flow chart of a method for resetting a frequency interval provided in an embodiment of the present application, wherein the resetting of the frequency interval based on the trend information by adjusting the center frequency and the bandwidth includes steps S201 to S203, wherein:

[0092] S201: Determine a target center frequency of the microwave cavity filter based on a frequency change direction and rate of an input signal in the trend information; wherein the target center frequency is determined based on an offset between a center frequency of a current frequency interval and a frequency change trend;

[0093] S202: Determine a target bandwidth of the microwave cavity filter based on a frequency variation range of the input signal;

[0094] S203: Based on the trend information, determine the time point when the input signal exceeds the current frequency interval, and before the time point, adjust the current center frequency to the target center frequency, and at the same time, adjust the current bandwidth to the target bandwidth to form a new frequency interval.

[0095] In a specific implementation, in order to adapt to the continuous frequency change trend of the input signal, after the system obtains the trend information through the detection module 10, the control module 20 resets the frequency interval by synchronously adjusting the center frequency and bandwidth, thereby ensuring that the system maintains a stable response when the frequency offset is large. First, based on the frequency change direction and rate in the trend information, the system determines the target center frequency. The direction of change in the trend information is used to determine the offset trend of the input signal frequency. For example, when the frequency gradually rises, the target center frequency will shift above the current center frequency, and when the frequency trend decreases, the target center frequency will move down accordingly. The system will also take into account the rate of change in the trend information, and add or subtract an offset according to the center frequency of the current frequency interval to ensure that the target center frequency can accurately match future changes in the signal frequency.

[0096] Next, the system determines the target bandwidth based on the frequency variation range of the input signal. The purpose of adjusting the bandwidth is to ensure that the new frequency range can fully cover the fluctuation range of the signal. When the signal fluctuates greatly, the system will appropriately expand the bandwidth so that the new frequency range increases the tolerance based on the offset center frequency; conversely, when the fluctuation is small, the bandwidth is reduced accordingly to maintain frequency selectivity. The setting of the target bandwidth reflects the frequency variation range. Through the appropriate bandwidth width, the filter can cover the offset amplitude of the input signal and avoid the signal quality degradation caused by the frequency offset exceeding the current interval.

[0097] At the same time, the control module 20 will predict the time point when the signal frequency exceeds the current frequency interval based on the trend information, and ensure that the synchronous adjustment of the center frequency and bandwidth is completed before this time point. In order to achieve early adjustment, the system smoothly adjusts the center frequency to the target center frequency within the time period of the frequency change prediction, and gradually expands or reduces the bandwidth to the target bandwidth to form a new frequency interval to cover the frequency changes of future signals. In this way, the system can make response adjustments before the signal deviates outside the current frequency interval to ensure signal stability.

[0098] In this way, by synchronously adjusting the center frequency and bandwidth based on trend information, the microwave cavity filter system of the present invention realizes adaptive tuning of the frequency range, so that the filter can always provide efficient signal response under the condition of continuous change of signal frequency. This solution not only improves the adaptive ability of the system, but also significantly improves the filter response speed in a dynamic signal environment.

[0099] As an optional implementation, the bandwidth adjustment also includes: when performing bandwidth adjustment, detecting a quality indicator of the input signal; wherein the quality indicator includes: a signal-to-noise ratio; in response to the signal-to-noise ratio of the input signal being less than an acceptable threshold, using a third tuning unit to reset the frequency range through center frequency adjustment and bandwidth adjustment.

[0100] In a specific implementation, in order to ensure that the quality of the input signal is maintained within an acceptable range during the bandwidth adjustment process, the system will detect the quality index of the signal in real time while adjusting the bandwidth. The quality index mainly includes the signal-to-noise ratio (SNR), which is used to reflect the purity and stability of the signal. During the bandwidth expansion process, the boundary of the filter frequency range is expanded outward to cover larger signal frequency fluctuations. However, the expansion of the bandwidth may introduce additional noise and non-target frequency signals, thereby affecting the quality of the signal. Therefore, during the bandwidth adjustment, the system monitors the signal-to-noise ratio in real time through the detection module 10, and compares the signal-to-noise ratio value with the preset acceptable threshold.

[0101] When the signal-to-noise ratio remains above the acceptable threshold, the bandwidth adjustment is performed within a predetermined range to ensure adaptive adjustment of the signal frequency range. However, if the signal-to-noise ratio is detected to be lower than the acceptable threshold during the adjustment process, it indicates that the current bandwidth expansion introduces too much noise or interference, which may affect the signal quality. At this time, the control module 20 determines that the bandwidth adjustment can no longer cover the fluctuation of the input signal without affecting the signal quality, and thus triggers the third tuning unit to perform a more refined adjustment.

[0102] Specifically, when the signal-to-noise ratio is lower than the acceptable threshold, the system uses the third tuning unit to synchronously adjust the center frequency and bandwidth to reset the frequency range. The third tuning unit first recalculates the target center frequency based on the trend information so that the newly set center frequency can be closer to the actual change trend of the signal. Then, the bandwidth is adjusted to a suitable range to balance the fluctuation of the signal and the selectivity of the filter to form a new frequency range. In this way, through the synchronous adjustment of the center frequency and bandwidth of the third tuning unit, the system can meet the frequency requirements of the input signal under the premise that the signal-to-noise ratio is restored to an acceptable level.

[0103] For example, if the signal-to-noise ratio is detected to drop below the preset threshold during the bandwidth expansion to 8.0 GHz to 8.6 GHz, the system immediately activates the third tuning unit to fine-tune the center frequency to a value that is more in line with the signal trend (such as 8.3 GHz), and moderately shrinks the bandwidth to 8.1 GHz to 8.5 GHz. By resetting the frequency range, the introduction of excessive noise is avoided, and the signal quality returns to an acceptable level, while still being able to adapt to the frequency change trend of the signal.

[0104] In this way, the mechanism of real-time monitoring of the signal-to-noise ratio and timely feedback during the bandwidth adjustment process enables the system to effectively maintain signal quality in a dynamic environment. Even when the frequency fluctuates greatly, through the feedback tuning of the signal-to-noise ratio detection, the system can better adapt to frequency changes and avoid quality loss caused by over-adjustment, thereby ensuring the stability of the filter and signal purity.

[0105] As an optional implementation manner, in response to the signal-to-noise ratio of the input signal being less than an acceptable threshold, resetting the frequency interval by adjusting the center frequency and the bandwidth using the third tuning unit includes:

[0106] Based on the quality index of the input signal, determining the rate of decrease of the signal-to-noise ratio, and based on the partial proportional relationship between the rate of decrease and the center frequency of the current frequency interval, setting the target center frequency of the microwave cavity filter; the bandwidth remains unchanged in this process;

[0107] In response to the target center frequency being set, the quality index of the input signal is detected, and based on the change of the signal-to-noise ratio, the bandwidth of the microwave cavity filter is gradually reduced until the signal-to-noise ratio is restored to above the acceptable threshold.

[0108] As an optional implementation manner, setting the target center frequency of the microwave cavity filter includes:

[0109] Based on the decrease rate of the signal-to-noise ratio, the current center frequency is offset according to a preset proportional relationship to set a target center frequency of the microwave cavity filter, where the target center frequency is equal to the current center frequency plus the decrease rate multiplied by a preset proportional coefficient.

[0110] As an optional implementation manner, the step of gradually reducing the bandwidth of the microwave cavity filter includes:

[0111] Based on the increment of signal-to-noise ratio recovery, the bandwidth of the microwave cavity filter is gradually reduced based on a preset bandwidth reduction ratio.

[0112] In the specific implementation, when the signal-to-noise ratio is lower than the acceptable threshold, the system will make fine adjustments to the center frequency and bandwidth through the third tuning unit to reset the frequency interval to restore the signal quality. Specifically, the system will first determine the rate of decrease of the signal-to-noise ratio through the quality index of the signal, and set a target center frequency based on the relationship between the rate and the center frequency of the current frequency interval. The setting of the target center frequency is based on the rate of decrease of the signal-to-noise ratio, and is calculated through the partial proportional relationship with the current center frequency. In the process of determining the target center frequency, the bandwidth remains unchanged to concentrate resources to stabilize the center frequency position of the signal and ensure that the basic framework of the frequency interval of the system remains consistent during the adjustment process. After completing the center frequency setting, the system will continue to detect the quality indicators of the input signal, especially the changes in the signal-to-noise ratio.

[0113] When the target center frequency is set, the system will gradually reduce the bandwidth to improve the selectivity of the filter according to the change of the signal-to-noise ratio until the signal-to-noise ratio is restored to above the acceptable threshold. During the gradual reduction of the bandwidth, the system monitors the increment of the signal-to-noise ratio recovery. When the signal-to-noise ratio gradually increases, the system gradually reduces the bandwidth according to the preset reduction ratio and the degree of signal-to-noise ratio recovery, so that the filter gradually shrinks the frequency range and removes excess noise interference. The purpose of bandwidth adjustment is to ensure the purity of the signal while avoiding excessive contraction of the frequency range that affects the passage of the signal.

[0114] In addition, during the setting of the target center frequency, the system offsets the current center frequency by a certain amount to obtain the target center frequency based on the signal-to-noise ratio decrease rate and the preset proportional relationship. Specifically, the system offsets the current center frequency by a preset proportional coefficient according to the rate at which the signal-to-noise ratio decreases, and the final target center frequency will be equal to the current center frequency plus the signal-to-noise ratio decrease rate multiplied by the proportional coefficient. The center frequency set in this way can accurately reflect the dynamic offset of the signal, allowing the system tuning to quickly follow the signal changes and avoid signal loss or interference caused by excessive frequency offset.

[0115] During the bandwidth adjustment process, the system uses the recovery increment of the signal-to-noise ratio as a feedback basis to reduce the bandwidth in proportion. When the signal-to-noise ratio reaches or exceeds the acceptable threshold, the system maintains the set bandwidth range and stops further adjustment. This bandwidth reduction strategy effectively reduces noise interference in non-target frequency bands by gradually tightening the frequency range, improving signal quality and system stability. This tuning method realizes real-time control and adaptive adjustment of the input signal quality, allowing the system to maintain stable output under signal change conditions.

[0116] For example, in a communication system, the filter needs to ensure that the purity of the signal is not less than a signal-to-noise ratio level of 20 dB. To this end, the performance of the system under different signal-to-noise ratio conditions was measured in an experimental environment, and it was found that when the signal-to-noise ratio was lower than 18 dB, the signal quality decreased significantly and the bit error rate at the receiving end increased significantly. Therefore, the acceptable signal-to-noise ratio threshold is set to 20 dB, that is, during the tuning process of the filter, once the signal-to-noise ratio is detected to be lower than 20 dB, the system will start the third tuning unit to synchronize the center frequency and bandwidth to ensure that the signal purity remains within an acceptable range.

[0117] For example, in the actual operation of the filter, when the signal-to-noise ratio decreases at a rate of 2 dB per second, if the current center frequency is directly offset by 0.05 GHz, the signal offset trend can be effectively followed; and when the signal-to-noise ratio decreases at a rate of 4 dB per second, the offset needs to be increased to 0.1 GHz to compensate for signal changes in a timely manner. Based on this experimental data, the proportional relationship set in the system is: a signal-to-noise ratio decrease rate of 1 dB per second corresponds to a frequency offset of 0.025 GHz. In other words, if the signal-to-noise ratio is detected to decrease by 3 dB per second, the system will set the target center frequency with a frequency offset of 3 times 0.025 GHz, or 0.075 GHz, to ensure that the filter quickly follows the frequency changes of the signal.

[0118] For example, in a radar signal processing, the signal frequency may fluctuate greatly in different working modes. Assume that it is observed in the signal processing experiment that when the signal-to-noise ratio decreases at a rate of 3 dB per second, the system can better follow the signal fluctuation when the proportional coefficient is set to 0.02. The proportional coefficient is used to convert the signal-to-noise ratio decrease rate into the adjustment amplitude of the center frequency. When the signal-to-noise ratio decrease rate is detected to be 5 dB per second, the system will offset the current center frequency by 0.1 GHz (5 dB × 0.02) through the proportional coefficient 0.02, thereby setting a new target center frequency and achieving frequency adjustment.

[0119] For example, in a wideband communication system, the filter bandwidth is initially set to 0.5 GHz to cover input signal fluctuations. Experiments have shown that the signal-to-noise ratio can be improved by 3 dB by reducing the bandwidth by 0.1 GHz (about 20%) each time. Therefore, the system sets the bandwidth reduction ratio to 20%, that is, gradually reducing the bandwidth until the signal-to-noise ratio returns to above the acceptable threshold. Assuming that the bandwidth is initially set to 0.5 GHz, the bandwidth can be gradually reduced to 0.3 GHz, and the signal-to-noise ratio is restored to above 20 dB, meeting the signal quality requirements of the system.

[0120] For example, in a mobile signal environment, the filter needs to cope with the trend of frequency drift over time. The system has observed through experiments that the signal frequency generally completes a drift cycle within 5 seconds. Therefore, the system sets the time period to 5 seconds, that is, once it detects that the frequency in the trend information will exceed the current frequency range, the system will complete the synchronous adjustment of the center frequency and bandwidth within the next 5 seconds, so that the new frequency range can cover the future change range of the signal. This setting ensures that the system can complete tuning in advance within 5 seconds, and there will be no loss of signal quality due to frequency drift.

[0121] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0122] It should be understood that determining B based on A does not mean determining B only based on A. B can also be determined based on A and / or other information.

[0123] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0124] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0125] The preferred embodiments of the present invention disclosed above are only used to help explain the present application. The preferred embodiments do not describe all the details in detail, nor do they limit the present application to specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can understand and use the present application well. The present application is limited only by the claims and their full scope and equivalents.

Claims

1. A microwave cavity filter system with automatic tuning function, characterized in that: include: A detection module, used for detecting frequency fluctuation of an input signal and generating fluctuation information; A control module, configured to determine a frequency interval adjustment requirement and generate adjustment information based on a relationship between the fluctuation information and a current frequency interval of the microwave cavity filter; Based on the adjustment information, dynamically adjusting the frequency range of the microwave cavity filter; The dynamic adjustment includes: in response to the fluctuation amplitude in the fluctuation information being less than a first threshold, adjusting the current frequency interval by using the first tuning unit through compensation adjustment; wherein the first threshold is determined based on the compensation capability of the first tuning unit; In response to the fluctuation amplitude in the fluctuation information being greater than or equal to a first threshold and less than a second threshold, adjusting the current frequency interval by using the second tuning unit through bandwidth adjustment; wherein the second threshold is determined based on the bandwidth adjustment capability of the second tuning unit and the compensation capability of the first tuning unit; In response to the fluctuation amplitude in the fluctuation information being greater than or equal to a second threshold, or the fluctuation information containing trend information, resetting the frequency interval by adjusting the center frequency and the bandwidth based on the fluctuation information using a third tuning unit; The dynamic adjustment further includes: performing a first boundary detection on the fluctuation information, and determining that trend information exists in the fluctuation information in response to the frequency of the input signal exceeding a current frequency interval within a future preset time period.

2. The microwave cavity filter system with automatic tuning function according to claim 1, characterized in that: The first tuning unit is used for: The center frequency of the current frequency interval is not adjusted, and the upper boundary or the lower boundary of the current frequency interval is adjusted by changing the value of the variable capacitor or the adjustable inductor in the microwave cavity filter.

3. The microwave cavity filter system with automatic tuning function according to claim 2, characterized in that: The second tuning unit is used to: not adjust the center frequency of the current frequency interval, and expand the bandwidth of the current frequency interval through the adjustable bandwidth element in the microwave cavity filter.

4. The microwave cavity filter system with automatic tuning function according to claim 3, characterized in that: The performing a first boundary detection on the fluctuation information, in response to the frequency of the input signal exceeding the current frequency interval within a future preset time period, determining that trend information exists in the fluctuation information includes: Performing a first boundary detection on the fluctuation information to determine whether there is trend information in the fluctuation information; The first boundary detection includes: performing trend analysis on the fluctuation information based on historical power spectrum density information of the input signal to determine the direction and rate of continuous change of the frequency of the input signal; Based on the continuous change direction and rate of the frequency of the input signal, the change of the frequency of the input signal in a future preset time period is determined; in response to the frequency of the input signal exceeding the current frequency range in a future preset time period, it is determined that there is trend information in the fluctuation information.

5. The microwave cavity filter system with automatic tuning function according to claim 4, characterized in that: The resetting of the frequency interval based on the fluctuation information by adjusting the center frequency and the bandwidth includes: Determine the target center frequency of the microwave cavity filter based on the frequency change direction and rate of the input signal in the trend information; wherein the target center frequency is determined based on the offset between the center frequency of the current frequency interval and the frequency change trend; Determining a target bandwidth of the microwave cavity filter based on a frequency variation range of the input signal; Based on the trend information, a time point when the input signal exceeds the current frequency range is determined, and before the time point, the current center frequency is adjusted to the target center frequency, and at the same time, the current bandwidth is adjusted to the target bandwidth to form a new frequency range.

6. The microwave cavity filter system with automatic tuning function according to claim 5, characterized in that: The bandwidth adjustment further includes: When performing bandwidth adjustment, detecting a quality indicator of the input signal; wherein the quality indicator includes: a signal-to-noise ratio; In response to the signal-to-noise ratio of the input signal being less than an acceptable threshold, the frequency interval is reset by adjusting the center frequency and the bandwidth using the third tuning unit.

7. The microwave cavity filter system with automatic tuning function according to claim 6, characterized in that: In response to the signal-to-noise ratio of the input signal being less than an acceptable threshold, resetting the frequency interval by adjusting the center frequency and the bandwidth using the third tuning unit comprises: Based on the quality index of the input signal, determining the rate of decrease of the signal-to-noise ratio, and based on the partial proportional relationship between the rate of decrease and the center frequency of the current frequency interval, setting the target center frequency of the microwave cavity filter; the bandwidth remains unchanged in this process; In response to the target center frequency being set, the quality index of the input signal is detected, and based on the change of the signal-to-noise ratio, the bandwidth of the microwave cavity filter is gradually reduced until the signal-to-noise ratio is restored to above the acceptable threshold.

8. The microwave cavity filter system with automatic tuning function according to claim 7, characterized in that: The step of setting the target center frequency of the microwave cavity filter comprises: Based on the decrease rate of the signal-to-noise ratio, the current center frequency is offset according to a preset proportional relationship to set a target center frequency of the microwave cavity filter, where the target center frequency is equal to the current center frequency plus the decrease rate multiplied by a preset proportional coefficient.

9. The microwave cavity filter system with automatic tuning function according to claim 8, characterized in that: The step of gradually reducing the bandwidth of the microwave cavity filter comprises: Based on the increment of signal-to-noise ratio recovery, the bandwidth of the microwave cavity filter is gradually reduced based on a preset bandwidth reduction ratio.

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