A device and method for dynamically tracking microwave resonator parameters

Abstract

The application discloses a kind of dynamic tracking microwave resonance cavity parameter device and method, belong to cigarette process quality inspection technical field, the device of the present application includes industrial computer, microwave signal source module, first isolator, microwave resonance cavity, second isolator and microwave detection module;Industrial computer, microwave signal source module, first isolator, microwave resonance cavity, second isolator and microwave detection module are sequentially connected by line;The method of the present application includes the following steps: determine whether the device is in idle state, if in non-idle state, then wait until idle;The cavity of microwave resonance cavity is swept frequency;Calculate the parameter of microwave resonance cavity cavity state;Next time measurement is based on the last resonance cavity cavity parameter setting this measurement microwave band.Utilize the idle time of system to calculate the cavity parameter of microwave resonance cavity to achieve the purpose of dynamic tracking, improve the calculation precision, and the cavity parameter of microwave resonance cavity can be accurately obtained.

Description

Technical Field

[0001] This invention belongs to the field of cigarette manufacturing quality inspection technology, specifically relating to a device and method for dynamically tracking microwave resonant cavity parameters. Background Technology

[0002] Moisture content and density of cigarettes are two crucial indicators in the quality control of cigarette manufacturing processes. They affect not only the intrinsic quality of the cigarettes but also their physical properties such as hardness, draw resistance, and burning speed. Traditional manual testing uses an oven weighing method, which is labor-intensive and time-consuming. The microwave resonant cavity perturbation method can effectively replace manual testing, enabling rapid detection of cigarette moisture and density. However, the key parameters of the microwave resonant cavity are easily affected by environmental interference, significantly impacting the accuracy of the measurement. Summary of the Invention

[0003] In view of the above-mentioned technical problems in the prior art, the present invention proposes a device and method for dynamically tracking microwave resonant cavity parameters. The device and method are reasonably designed, overcome the shortcomings of the prior art, and have good effects.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A device for dynamically tracking microwave resonant cavity parameters includes an industrial control computer, a microwave signal source module, a first isolator, a microwave resonant cavity, a second isolator, and a microwave detection module; the industrial control computer, microwave signal source module, first isolator, microwave resonant cavity, second isolator, and microwave detection module are connected sequentially via lines;

[0006] Industrial control computers are configured to transmit microwave signals and analyze and process data.

[0007] The microwave signal source module is configured to perform microwave frequency sweeping;

[0008] Both the first isolator and the second isolator are configured for signal isolation;

[0009] A microwave resonant cavity is configured to conduct microwave signals;

[0010] The microwave detector module is configured to convert microwave amplitude into a voltage signal;

[0011] The microwave signal is transmitted under the control of an industrial control computer. After passing through the microwave resonant cavity, the microwave signal data is uploaded to the industrial control computer through a microwave detection module, where the industrial control computer performs data analysis and processing.

[0012] Preferably, the microwave resonant cavity is a microwave dielectric cavity composed of a circular metal shell and a ceramic dielectric.

[0013] Preferably, the frequency range of the microwave signal source module is 0 GHz to 6 GHz.

[0014] Furthermore, this invention also provides a method for dynamically tracking microwave resonant cavity parameters. This method employs a device for dynamically tracking microwave resonant cavity parameters as described above, and specifically includes the following steps:

[0015] Step 1: Determine if the device is in an idle state. If it is not in an idle state, wait until it becomes idle.

[0016] Step 2: Sweep the frequency of the microwave resonant cavity at a specified step to obtain the power-frequency curve of the microwave resonant cavity;

[0017] Step 3: Calculate the parameters of the microwave resonant cavity state, including resonant frequency, resonant amplitude, and bandwidth.

[0018] Step 4: For the next measurement, set the microwave frequency band for this measurement based on the cavity parameters of the most recent resonant cavity.

[0019] Preferably, step 3, the method for calculating the cavity parameters of the microwave resonant cavity, specifically includes the following steps:

[0020] Step 3.1: Perform a moving average filter on the cavity sweep frequency signal to reduce random noise and make the signal smoother;

[0021] Step 3.2: Traverse the signal to find the peak points, obtain the resonant frequency and resonant amplitude, and obtain the half-power point based on the resonant amplitude;

[0022] Step 3.3: Based on the half-power point traversal, the lower cutoff frequency range of the signal is initially located. Several points near this frequency range are selected for least squares linear fitting to obtain a more refined lower cutoff frequency.

[0023] Step 3.4: Based on the half-power point traversal, the upper cutoff frequency range of the signal is initially located. Several points near this frequency range are then subjected to least-squares linear fitting to obtain a more refined upper cutoff frequency.

[0024] Step 3.5: Calculate the half-power bandwidth based on the upper and lower cutoff frequencies.

[0025] The beneficial technical effects of this invention are as follows:

[0026] This invention utilizes the system's idle time to calculate the cavity parameters of the microwave resonator to achieve dynamic tracking. Furthermore, the method for calculating the cavity parameters of the microwave resonator improves the calculation accuracy, allowing for precise acquisition of the cavity parameters. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the device for dynamically tracking microwave resonant cavity parameters according to the present invention;

[0028] Figure 2 This is a flowchart illustrating the method for dynamically tracking microwave resonant cavity parameters according to the present invention.

[0029] Figure 3 The flowchart shows the algorithm for calculating microwave resonant cavity parameters in this invention.

[0030] Figure 4 This is a schematic diagram of the algorithm for calculating microwave resonant cavity parameters according to the present invention;

[0031] Among them, 1-industrial control computer; 2-microwave signal source module; 3-first isolator; 4-microwave resonant cavity; 5-second isolator; 6-microwave detection module. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0033] The device for dynamically tracking microwave resonant cavity parameters of this invention is attached. Figure 1 As shown, the device consists of an industrial control computer 1, a microwave signal source module 2, a first isolator 3, a microwave resonant cavity 4, a second isolator 5, and a microwave detection module 6. In this embodiment, the industrial control computer controls the microwave signal source module to produce frequency signals within a specified range. After passing through the microwave resonant cavity, the microwave signal is converted into an electrical signal by the microwave detection module and transmitted to the industrial control computer for analysis and processing.

[0034] The method and flowchart for dynamically tracking microwave resonant cavity parameters are attached. Figure 2 As shown, the system exists in two states: working state and idle state. In the working state, a cigarette will pass through the microwave resonant cavity, making it impossible to obtain the cavity parameters. Therefore, the system must wait until it reaches the idle state. When the system is idle, the industrial control computer controls the microwave signal source module to generate a microwave signal to sweep the frequency of the microwave resonant cavity. After obtaining the swept signal data, the specific resonant frequency, resonant amplitude, bandwidth, and other cavity parameters are calculated to compensate for the next cigarette measurement data.

[0035] The method for calculating microwave resonant cavity parameters can be combined with the appendix. Figure 3 and attached Figure 4 The specific algorithm is as follows:

[0036] Step 3.1: Perform a moving average filter on the cavity sweep frequency signal to reduce random noise and make the signal smoother;

[0037]

[0038] In the formula, p is the filtering result at the i-th frequency point. i-k p i pi+k are the original powers at the ik, i, and i+k frequency points respectively, and 2n+1 is the sliding window length;

[0039] Step 3.2: Traverse the signal to find peak points, obtain the resonant frequency and resonant amplitude, and obtain the half-power point p based on the resonant amplitude. half (-3dB);

[0040] Step 3.3: Based on the half-power point traversal, the lower cutoff frequency range of the signal is initially located. Several points near this frequency range are selected for least squares linear fitting to obtain a more refined lower cutoff frequency.

[0041] The coordinates of several points near this frequency range are (f1, p1), (f2, p2), ..., (f...). n ,p n It can be approximated as a straight line.

[0042] p = A L f+B L

[0043] Among them, A L Let B be the slope. L f is the intercept, and f is the frequency;

[0044] Calculate the residual sum of squares S based on the least squares criterion:

[0045]

[0046] A is obtained by calculating the minimum value of S. L B L ;

[0047] The lower cutoff frequency f can be calculated based on the half-power point. L ;

[0048] f L =(p half -B L ) / A L .

[0049] Step 3.4: Based on the half-power point traversal, the upper cutoff frequency range of the signal is initially located. Several points near this frequency range are then subjected to least-squares linear fitting to obtain a more refined upper cutoff frequency.

[0050] The coordinates of several points near this frequency range are (f1, p1), (f2, p2), ..., (f...). n ,p n It can also be approximated as a straight line.

[0051] p = A H f+B H

[0052] Among them, A H Let B be the slope. H This is the intercept.

[0053] Based on the least squares criterion, we obtain

[0054]

[0055] Calculating the minimum value of S yields A. H B H The upper cutoff frequency f can be calculated based on the half-power point. H ;

[0056] f H =(p half -B H ) / A H

[0057] Step 3.5: Calculate the half-power bandwidth bw based on the upper and lower cutoff frequencies.

[0058] bw=f H -f L

[0059] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for dynamically tracking microwave resonant cavity parameters, characterized in that: A device for dynamically tracking microwave resonant cavity parameters is employed. The device includes an industrial control computer, a microwave signal source module, a first isolator, a microwave resonant cavity, a second isolator, and a microwave detection module. The industrial control computer, microwave signal source module, first isolator, microwave resonant cavity, second isolator and microwave detector module are connected in sequence by a line; Industrial control computers are configured to transmit microwave signals and analyze and process data. The microwave signal source module is configured to perform microwave frequency sweeping; Both the first isolator and the second isolator are configured for signal isolation; A microwave resonant cavity is configured to conduct microwave signals; The microwave detector module is configured to convert microwave amplitude into a voltage signal; The microwave signal is transmitted under the control of an industrial control computer. After passing through the microwave resonant cavity, the microwave signal data is uploaded to the industrial control computer via a microwave detection module, where it is analyzed and processed. The specific steps include: Step 1: Determine if the device is in an idle state. If it is not in an idle state, wait until it becomes idle. Step 2: Sweep the frequency of the microwave resonant cavity at a specified step to obtain the power-frequency curve of the microwave resonant cavity; Step 3: Calculate the parameters of the microwave resonant cavity state, including resonant frequency, resonant amplitude, and bandwidth. Step 4: For the next measurement, set the microwave frequency band for this measurement based on the cavity parameters of the most recent resonant cavity; Step 3, the method for calculating the cavity parameters of the microwave resonant cavity, specifically includes the following steps: Step 3.1: Perform moving average filtering on the cavity sweep frequency signal; Step 3.2: Traverse the signal to find the peak points, obtain the resonant frequency and resonant amplitude, and obtain the half-power point based on the resonant amplitude; Step 3.3: Based on the half-power point traversal, the lower cutoff frequency range of the signal is initially located. Several points near this frequency range are selected for least squares linear fitting to obtain the lower cutoff frequency. Step 3.4: Based on the half-power point traversal, the upper cutoff frequency range of the signal is initially located. Several points near this frequency range are selected for least squares linear fitting to obtain the upper cutoff frequency. Step 3.5: Calculate the half-power bandwidth based on the upper and lower cutoff frequencies.

2. The method for dynamically tracking microwave resonant cavity parameters according to claim 1, characterized in that: A microwave resonant cavity is a microwave dielectric cavity composed of a circular metal shell and a ceramic dielectric.

3. The method for dynamically tracking microwave resonant cavity parameters according to claim 1, characterized in that: The frequency range of the microwave signal source module is 0 GHz to 6 GHz.

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