Power line communication signal quality improvement method based on discrete Fourier transform

Abstract

The invention relates to the technical field of signal processing, in particular to a power line communication signal quality improvement method based on discrete Fourier transform, which comprises the following steps: decomposing a time domain signal corresponding to a target power line communication signal into n frequency components through discrete Fourier transform, and obtaining a frequency component sorting result, matching the frequency domain signal corresponding to each frequency component with a plurality of pre-acquired interference signals to screen out an interference signal set corresponding to each frequency component, and then acquiring a plurality of frequency component groups and a target matching degree corresponding to each frequency component group to screen out a target frequency group from the plurality of frequency component groups, calculating a frequency group score corresponding to each target frequency group, and filtering partial frequency components according to the frequency group scores; according to the invention, the interference signal can be effectively filtered in a targeted manner, and the reliability and great improvement of the quality of the power line communication signal are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of signal processing, and in particular to a method for improving the quality of power line communication signals based on discrete Fourier transform. Background Art

[0002] Discrete Fourier Transform (DFT) is an important transformation in the field of signal analysis. This transformation is a mathematical method for converting time domain signals into frequency domain signals. It can decompose complex time domain signals into several simple frequency components. At present, various signals can be processed efficiently by computers. The signals processed by computers are all discrete and finite signals. Analyzing discrete and finite signals is an important part of signal analysis. For example, the transmission principle of power line communication signals is to load the high frequency carrying information onto the current and then transmit the high frequency signal through the power line. The adapter at the receiving end then separates the high frequency signal from the current and transmits it to the computer or phone to realize information transmission. During transmission, the high frequency signal will be mixed with multiple interference signals. How to specifically screen out the interference signals is crucial to improving the quality of power line communication signals. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a method for improving the quality of power line communication signals based on discrete Fourier transform, which can effectively filter out interference signals in a targeted manner and achieve reliable and substantial improvement in the quality of power line communication signals.

[0004] The present invention provides a method for improving the quality of power line communication signals based on discrete Fourier transform, comprising the following steps: The time domain signal corresponding to the target power line communication signal is decomposed into n frequency components by discrete Fourier transform, and the n frequency components are sorted from small to large to obtain the frequency component sorting result.

[0005] The frequency domain signal corresponding to each frequency component is matched with a plurality of pre-acquired interference signals, and the interference signal set corresponding to each frequency component is obtained by screening according to the matching degree.

[0006] A number of frequency components are grouped with the number of groups being 1 to n to obtain a number of frequency component groups, and according to the matching degree between each frequency component and each interference signal in the corresponding interference signal set, the target matching degree corresponding to each frequency component group is calculated.

[0007] Based on a preset signal quality improvement threshold and a number of target matching degrees after normalization, a target frequency group is screened out from a number of frequency component groups.

[0008] According to the number of frequency components in each target frequency group and the position of the frequency components in the frequency component sorting result, the frequency group score corresponding to each target frequency group is calculated, and the frequency component in the target frequency group corresponding to the smallest frequency group score is filtered out from the n frequency components corresponding to the target power line communication signal to obtain the final frequency domain signal corresponding to the target power line communication signal.

[0009] The present invention has at least the following beneficial effects: The present invention provides a method for improving the quality of power line communication signals based on discrete Fourier transform. First, a time domain signal corresponding to a target power line communication signal is decomposed into a plurality of frequency components by discrete Fourier transform, and a frequency component sorting result is obtained. The frequency domain signal corresponding to each frequency component is matched with a plurality of pre-acquired interference signals to screen out an interference signal set corresponding to each frequency component, that is, to determine an interference signal with a greater impact on each frequency component, so as to grasp the impact of the interference signal under each frequency component. Then, based on the plurality of frequency components, a plurality of frequency component groups and a target matching degree corresponding to each frequency component group are obtained, so as to reflect the interference situation corresponding to each frequency component group, so as to screen out a target frequency group that meets the requirements from the plurality of frequency component groups. Finally, a frequency group score corresponding to each target frequency group is calculated, and targeted frequency component filtering is implemented according to the frequency group score, so as to realize reliable and substantial improvement of the quality of power line communication signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0011] Figure 1 A flowchart of a method for improving power line communication signal quality based on discrete Fourier transform provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0012] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0013] The embodiment of the present invention provides a method for improving the quality of power line communication signals based on discrete Fourier transform, such as Figure 1 As shown, the method comprises the following steps: S100, decomposing the time domain signal corresponding to the target power line communication signal into n frequency components through discrete Fourier transform, and sorting the n frequency components from small to large to obtain a frequency component sorting result; it can be understood as: sorting the frequency components from small to large according to the frequency size corresponding to the frequency components.

[0014] Specifically, the time domain signal corresponding to the target power line communication signal is decomposed into several frequency components by discrete Fourier transform, as shown below: For a discrete time series x[m] of length M, m=0, 1, ...M-1, after discrete Fourier transform, it is X[k]=∑ M-1 m=1 x[m]e -jkm×2π / M , where j is an imaginary unit, and k=0, 1, ...M-1. Since converting a time domain signal into a frequency domain signal by discrete Fourier transform is an existing technology, it will not be described in detail here.

[0015] S200, matching the frequency domain signal corresponding to each frequency component with a plurality of pre-acquired interference signals, and obtaining the interference signal set corresponding to each frequency component by screening according to the matching degree.

[0016] Specifically, the interference signal refers to any signal pre-extracted from the initial power line communication signal that interferes with the target power line communication signal.

[0017] In a specific embodiment, step S200 includes the following steps: S201 , calculating the matching degree between the frequency domain signal corresponding to each frequency component and a plurality of pre-acquired interference signals, and obtaining the matching degree between the frequency domain signal corresponding to each frequency component and each interference signal.

[0018] Furthermore, the matching degree between the frequency domain signal corresponding to the frequency component and the interference signal meets the following conditions: S=w 1 ×d 1 +w 2 ×d 2 +w 3 ×d 3 , where S represents the matching degree between the frequency domain signal corresponding to any frequency component and any interference signal, and w 1 、w 2 and w 3 are the first preset weight, the second preset weight and the third preset weight respectively, d 1 is the Euclidean distance between the frequency domain signal and the frequency corresponding to the interference signal, d 2 is the Euclidean distance between the phase spectra of the frequency domain signal and the interference signal, d 3is the Euclidean distance between the amplitude spectra of the frequency domain signal and the interference signal. Wherein, obtaining the Euclidean distance between two parameters is known to those skilled in the art and will not be described in detail here.

[0019] As mentioned above, by comprehensively considering the frequency proximity between the frequency domain signal and the interference signal, as well as the similarity between their phase spectra and their amplitude spectra, the similarity between the frequency domain signal and the interference signal is compared, and the interference signal that is similar to each frequency component and has a greater impact can be determined, which is beneficial to the processing and improvement of signal quality.

[0020] S202: When the matching degree between the frequency domain signal corresponding to the frequency component and the interference signal is greater than a matching degree threshold, it is determined that the frequency component and the interference signal have a matching relationship.

[0021] S203, for any frequency component, select a plurality of interference signals that have a matching relationship with the frequency component and form an interference signal set corresponding to the frequency component.

[0022] As mentioned above, by calculating the degree of matching between each interference signal and the frequency component, interference signals similar to the frequency components can be screened out. Since the interference signal with a higher degree of matching has a greater impact on the power line communication signal, the interference signal with a greater impact on each frequency component is determined, and the impact of the interference signal under each frequency component can be understood, which is conducive to targeted and effective filtering of the interference signal, so that the signal quality improvement degree meets the required requirements.

[0023] S300, grouping a plurality of frequency components with the number of groups being 1 to n to obtain a plurality of frequency component groups, and calculating a target matching degree corresponding to each frequency component group according to a matching degree between each frequency component and each interference signal in a corresponding interference signal set.

[0024] Furthermore, the method obtains several frequency component groups through the following steps: S301, when the number of groups is i and i=1, a number of frequency components are grouped to obtain n first frequency component groups, wherein each first frequency component group includes one frequency component.

[0025] S302, when the number of frequency components in a group is i and 1<i≤n, a number of frequency components are grouped to obtain n-i+1 second frequency component groups, wherein each second frequency component group includes i frequency components and the i frequency components are continuous in the frequency component sorting result. For example, when there are 5 frequency components and i=3, 3 second frequency component groups are obtained, namely (frequency component 1, frequency component 2, frequency component 3), (frequency component 2, frequency component 3, frequency component 4), (frequency component 3, frequency component 4, frequency component 5).

[0026] In another implementation, when the second frequency component group includes i frequency components, the i frequency components may also be i frequency components randomly obtained from the frequency component sorting result.

[0027] S303: Obtain several frequency component groups based on the obtained first frequency component group and all the second frequency component groups.

[0028] Specifically, the method obtains the target matching degree corresponding to each frequency component group through the following steps: S310 , for any frequency component in any frequency component group, determine the sum of the matching degrees between the frequency component and each interference signal in the corresponding interference signal set as the total matching degree corresponding to the frequency component.

[0029] S320, normalizing the total matching degree corresponding to each frequency component, and for any frequency component group, determining the sum of the normalized total matching degrees corresponding to each frequency component in the frequency component group as the target matching degree corresponding to the frequency component group.

[0030] As described above, by obtaining the target matching degree corresponding to each frequency component group based on the matching degree between the frequency component and each interference signal in the corresponding interference signal set, the amount of interference corresponding to each frequency component group can be reflected, so as to achieve targeted frequency component filtering according to the signal quality improvement requirements.

[0031] S400, based on a preset signal quality improvement threshold and a number of target matching degrees after normalization processing, a target frequency group is screened out from a number of frequency component groups; it can be understood that: when the target matching degree after normalization processing is greater than the preset signal quality improvement threshold, the frequency component group corresponding to the target matching degree is screened out and used as the target frequency group.

[0032] S500, calculates the frequency group score corresponding to each target frequency group according to the number of frequency components in each target frequency group and the position of the frequency components in the frequency component sorting result, and filters out the frequency components in the target frequency group corresponding to the smallest frequency group score from the n frequency components corresponding to the target power line communication signal to obtain a final frequency domain signal corresponding to the target power line communication signal.

[0033] Specifically, the frequency group score corresponding to the target frequency group meets the following conditions: P c =ξ 1 ×Q c1 +ξ 2 ×Q c2 , where P c represents the frequency group score corresponding to the cth target frequency group, ξ 1 is the preset frequency component quantity weight, Qc1 is the number of frequency components in the cth target frequency group, ξ 2 is the preset distance weight, Q c2 It is the minimum distance between the cth target frequency group and the two ends of the frequency component sorting result.

[0034] Preferably, 1 >ξ 2 , considering the position relative to the frequency components, the fewer frequency components should be filtered out first, so the above setting is adopted. In the specific implementation, ξ 1 is 0.8, ξ 2 is 0.2.

[0035] Furthermore, the distances between the target frequency group and the two ends of the frequency component sorting result refer to the order quantity difference between the first frequency component in the target frequency group and the last frequency component in the frequency component sorting result and the order quantity difference between the last frequency component in the target frequency group and the first frequency component in the frequency component sorting result.

[0036] As mentioned above, when filtering out interference signals, in order to effectively reduce the impact on the quality of power line communication signals during filtering, fewer frequency components and frequency components with too large or too small frequencies should be filtered out first. Therefore, when calculating the frequency group score, the number of frequency components and the size of the frequencies are comprehensively considered, and the frequency components with relatively fewer numbers and closer to the edge of the sorting results are filtered out to ensure that the final frequency domain signal has a higher quality, thereby improving the quality of the power line communication signal.

[0037] In summary, the present invention provides a method for improving the quality of power line communication signals based on discrete Fourier transform. First, the time domain signal corresponding to the target power line communication signal is decomposed into several frequency components by discrete Fourier transform, and the frequency component sorting result is obtained. The frequency domain signal corresponding to each frequency component is matched with several pre-acquired interference signals to screen out the interference signal set corresponding to each frequency component, that is, to determine the interference signal with a greater impact on each frequency component, so as to grasp the impact of the interference signal under each frequency component, and then obtain several frequency component groups and the target matching degree corresponding to each frequency component group based on several frequency components, so as to reflect the interference situation corresponding to each frequency component group, so as to screen out the target frequency group that meets the requirements from several frequency component groups, and finally calculate the frequency group score corresponding to each target frequency group, and according to the frequency group score, the frequency component is filtered out in a targeted manner, so as to achieve reliable and substantial improvement in the quality of power line communication signals.

[0038] Although some specific embodiments of the present invention have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are only for illustration and not for limiting the scope of the present invention. It should also be understood by those skilled in the art that various modifications may be made to the embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the attached technical solutions.

Claims

1. A method for improving power line communication signal quality based on discrete Fourier transform, characterized in that: The method comprises the following steps: Decomposing the time domain signal corresponding to the target power line communication signal into n frequency components by discrete Fourier transform, and sorting the n frequency components from small to large to obtain a frequency component sorting result; The frequency domain signal corresponding to each frequency component is matched with a plurality of pre-acquired interference signals, and the interference signal set corresponding to each frequency component is obtained by screening according to the matching degree; A plurality of frequency components are grouped with the number of groups being 1 to n to obtain a plurality of frequency component groups, and a target matching degree corresponding to each frequency component group is calculated according to the matching degree between each frequency component and each interference signal in the corresponding interference signal set; Based on a preset signal quality improvement threshold and a number of target matching degrees after normalization processing, a target frequency group is selected from a number of frequency component groups; According to the number of frequency components in each target frequency group and the position of the frequency components in the frequency component sorting result, the frequency group score corresponding to each target frequency group is calculated, and the frequency component in the target frequency group corresponding to the smallest frequency group score is filtered out from the n frequency components corresponding to the target power line communication signal to obtain the final frequency domain signal corresponding to the target power line communication signal.

2. The method for improving power line communication signal quality based on discrete Fourier transform according to claim 1, characterized in that: The interference signal refers to any signal pre-extracted from the initial power line communication signal that interferes with the target power line communication signal.

3. The method for improving power line communication signal quality based on discrete Fourier transform according to claim 1, characterized in that: The interference signal set corresponding to each frequency component is obtained by screening through the following steps: The frequency domain signal corresponding to each frequency component is matched with a plurality of pre-acquired interference signals to obtain the matching degree between the frequency domain signal corresponding to each frequency component and each interference signal; When the matching degree between the frequency domain signal corresponding to the frequency component and the interference signal is greater than the matching degree threshold, it is determined that the frequency component and the interference signal have a matching relationship; For any frequency component, several interference signals having a matching relationship with the frequency component are screened out and form an interference signal set corresponding to the frequency component.

4. The method for improving power line communication signal quality based on discrete Fourier transform according to claim 3, characterized in that: The matching degree between the frequency domain signal corresponding to the frequency component and the interference signal meets the following conditions: S=w1×d1+w2×d2+w3×d3, where S represents the degree of matching between the frequency domain signal corresponding to any frequency component and any interference signal, w1, w2 and w3 are the first preset weight, the second preset weight and the third preset weight respectively, d1 is the Euclidean distance of the frequencies corresponding to the frequency domain signal and the interference signal, d2 is the Euclidean distance of the phase spectrum corresponding to the frequency domain signal and the interference signal, and d3 is the Euclidean distance of the amplitude spectrum corresponding to the frequency domain signal and the interference signal.

5. The method for improving power line communication signal quality based on discrete Fourier transform according to claim 1, characterized in that: Several frequency component groups are obtained by the following steps: When the number of groups is i and i=1, a number of frequency components are grouped to obtain n first frequency component groups, wherein each first frequency component group contains one frequency component; When the number of groups is i and 1<i≤n, a number of frequency components are grouped to obtain n-i+1 second frequency component groups, wherein each second frequency component group includes i frequency components and the i frequency components are continuous in the frequency component sorting result; Based on the obtained first frequency component group and all the second frequency component groups, several frequency component groups are obtained.

6. The method for improving power line communication signal quality based on discrete Fourier transform according to claim 1, characterized in that: The target matching degree corresponding to each frequency component group is obtained through the following steps: For any frequency component in any frequency component group, the sum of the matching degrees between the frequency component and each interference signal in the corresponding interference signal set is determined as the total matching degree corresponding to the frequency component; The total matching degree corresponding to each frequency component is normalized, and for any frequency component group, the sum of the normalized total matching degrees corresponding to each frequency component in the frequency component group is determined as the target matching degree corresponding to the frequency component group.

7. The method for improving power line communication signal quality based on discrete Fourier transform according to claim 1, characterized in that: The frequency group score corresponding to the target frequency group meets the following conditions: P c =ξ1×Q c1 +ξ2×Q c2 , where P c represents the frequency group score corresponding to the cth target frequency group, ξ1 is the preset frequency component quantity weight, Q c1 is the number of frequency components in the cth target frequency group, ξ2 is the preset distance weight, Q c2 It is the minimum distance between the cth target frequency group and the two ends of the frequency component sorting result.

8. The method for improving power line communication signal quality based on discrete Fourier transform according to claim 7, characterized in that: The distances between the target frequency group and the two ends of the frequency component sorting result refer to the order quantity difference between the first frequency component in the target frequency group and the last frequency component in the frequency component sorting result and the order quantity difference between the last frequency component in the target frequency group and the first frequency component in the frequency component sorting result.

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