CN103647610B - A kind of low-voltage power line communication channel impulse noise based on amplitude and width - Google Patents

Abstract

The invention relates to a low-voltage power line communication channel pulse noise detection method based on amplitude and width, and belongs to the technical field of communication noise detection. The present invention comprises steps: S1, sampling the noise of the power line communication channel; S2, calculating the absolute mean value of the sampling noise; S3, preset the highest pulse amplitude threshold value; S4, calculating the difference between the absolute value mean value and the highest threshold value ; S5, uniform segment difference; S6, compare the sampling noise with the minimum threshold of one segment of the pulse amplitude, if there is noise data greater than the minimum threshold of the pulse amplitude in the sampling data, then go to step S7, otherwise go to S8; S7 , judging whether the duration of the noise data greater than the minimum pulse amplitude threshold of one section is longer than the preset pulse duration threshold of this section; S8, judging whether the comparison of all the sections is over. The invention can detect and identify the impulse noise, and simultaneously improves the identification accuracy of the impulse noise.

Description

A low-voltage power line communication channel pulse noise detection method based on amplitude and width

technical field

The invention relates to a low-voltage power line communication channel pulse noise detection method based on amplitude and width, and belongs to the technical field of communication noise detection.

Background technique

With the advancement of technology, PLC technology is used to transmit high-speed data, images, voice and other media business signals with low-voltage power distribution lines, and is applied to home Internet (Internet) "broadband" access and intelligent networking control of home appliances, namely High speed data PLC. How to further improve the performance of low-voltage power line communication and realize high-speed and reliable long-distance communication depends on the grasp of the communication channel. The power line network is not specially designed for high-frequency signal transmission, so the power line network presents more and stronger factors that are not conducive to high-frequency signal transmission. Among these unfavorable factors, impulse noise is the main reason for the non-Gaussian, non-stationary and non-white noise characteristics of the power line channel, and is one of the important factors affecting the quality of power line communication. , pulse width and interval time decision.

A PLC channel pulse detection method in the prior art is to set a noise threshold value, and when the collected amplitude is greater than the noise threshold value, it is considered as pulse noise. The disadvantage of this method is that when the background noise in the current channel is relatively large, it is difficult to distinguish the background noise from the impulse noise, and the pulse duration under different amplitudes is ignored, so there is a large error in detecting the impulse noise .

Contents of the invention

The invention provides a low-voltage power line communication channel pulse noise detection method based on amplitude and width, which is used to solve the problem of detecting pulse noise in the low-voltage power line communication (PLC) channel.

The technical solution of the present invention is: a low-voltage power line communication channel pulse noise detection method based on amplitude and width, and the specific steps of the method are as follows:

Step S1, sampling the power line communication channel noise to obtain N sampling points d _i , i =0, 1, 2, 3,... N -1;

Step S2, calculate the absolute value mean of N sampling noise data: , i =0,1,2,3,... N -1;

Step S3, preset the maximum pulse amplitude threshold value V _max ;

Step S4, calculate the difference △ V between the highest threshold value and the absolute value mean: ;

Step S5, dividing the difference ΔV evenly into M segments;

Step S6, compare the sampling noise data d _i with the lowest pulse amplitude threshold of the j segment : if there is noise data greater than the minimum pulse amplitude threshold in the sampled data, then go to step S7, otherwise go to S8;

in, , j =0,2,3,... M -1;

Step S7, judging whether the duration t _j of the noise data greater than the minimum pulse amplitude threshold of the j segment is greater than the preset pulse duration T _j of the j segment: if it exceeds, it is judged that the data has pulse noise once, otherwise, it is judged that the segment Impulse noise does not appear;

in, , j =0,2,3,... M -1, t _max and t _min are respectively the maximum and minimum duration of an impulse noise;

Step S8, judging whether j is equal to M -1: if yes, then end and return; otherwise, go to step S6 to enter the next segment to continue the comparison.

The step S8, when it is judged that the comparison is over, further includes the following steps:

Step S81, sorting out the comparison results: if there is more than one segment where pulses appear, add up the pulse times of all segments where pulses appear to obtain all the pulse information of the entire segment of noise data.

In the step S1, the sampling frequency f _s for sampling the low-voltage power line communication channel noise meets the requirements of the Nyquist sampling theorem.

In the step S3, the value of V _max is selected such that V _max is greater than the mean value of the absolute value and less than the maximum value of the absolute value of the noise data.

Said step S7 also includes the following steps:

Step S71, if greater than the first If the noise data with the lowest pulse amplitude threshold of the segment is judged to have pulse noise, and the noise data duration t _j is much longer than the duration T _j , then this segment of noise data contains t _j / T _j pulses, j =0,2,3 ,... M -1.

The beneficial effects of the present invention are: the channel noise data is not only considered to be composed of background noise, but also includes the superposition of impulse noise; the impulse noise can be detected and identified; the multi-segment minimum impulse amplitude threshold is set for the channel sampling points The pulse noise can be judged according to the value and the design duration of each pulse, which improves the recognition accuracy of the pulse noise.

Description of drawings

Fig. 1 is a flowchart of the present invention;

Fig. 2 is a schematic flow chart of the working process in the present invention;

Fig. 3 is the time-domain waveform diagram of the pulse detection of Fig. 2 among the present invention;

FIG. 4 is a schematic diagram of the pulse detection result of FIG. 3 in the present invention.

detailed description

Embodiment 1: As shown in Figure 1-4, a low-voltage power line communication channel pulse noise detection method based on amplitude and width, the specific steps of the method are as follows:

Step S1, sampling the power line communication channel noise to obtain N sampling points d _i , i =0, 1, 2, 3,... N -1;

Step S2, calculate the absolute value mean of N sampling noise data: , i =0,1,2,3,... N -1;

Step S3, preset the maximum pulse amplitude threshold value V _max ;

Step S4, calculate the difference △ V between the highest threshold value and the absolute value mean: ;

Step S5, dividing the difference ΔV evenly into M segments;

Step S6, compare the sampling noise data d _i with the lowest pulse amplitude threshold of the j segment : if there is noise data greater than the minimum pulse amplitude threshold in the sampled data, then go to step S7, otherwise go to S8;

in, , j =0,2,3,... M -1;

Step S7, judging whether the duration t _j of the noise data greater than the minimum pulse amplitude threshold of the j segment is greater than the preset pulse duration T _j of the j segment: if it exceeds, it is judged that the data has pulse noise once, otherwise, it is judged that the segment Impulse noise does not appear;

in, , j =0,2,3,... M -1, t _max and t _min are respectively the maximum and minimum duration of an impulse noise;

Step S8, judging whether j is equal to M -1: if yes, then end and return; otherwise, go to step S6 to enter the next segment to continue the comparison.

The step S8, when it is judged that the comparison is over, further includes the following steps:

Step S81, sorting out the comparison results: if there is more than one segment where pulses appear, add up the pulse times of all segments where pulses appear to obtain all the pulse information of the entire segment of noise data.

In the step S1, the sampling frequency f _s for sampling the low-voltage power line communication channel noise meets the requirements of the Nyquist sampling theorem.

In the step S3, the value of V _max is selected such that V _max is greater than the mean value of the absolute value and less than the maximum value of the absolute value of the noise data.

Said step S7 also includes the following steps:

Step S71, if greater than the first If the noise data with the lowest pulse amplitude threshold of the segment is judged to have pulse noise, and the noise data duration t _j is much longer than the duration T _j , then this segment of noise data contains t _j / T _j pulses, j =0,2,3 ,... M -1.

Embodiment 2: As shown in Figure 1-4, a low-voltage power line communication channel pulse noise detection method based on amplitude and width, the specific steps of the method are as follows:

Step S1, sampling the power line communication channel noise to obtain N sampling points d _i , i =0, 1, 2, 3,... N -1;

More preferably, in the step S1, the sampling frequency f _s for sampling the low-voltage power line communication channel noise is sufficiently large so that the sampling process meets the requirements of Nyquist sampling theorem;

Step S2, calculate the absolute value mean of N sampling noise data: , i =0,1,2,3,... N -1;

Step S3, preset the maximum pulse amplitude threshold value V _max ;

In the step S3, the value of V _max is selected so that V _max is greater than the mean value of the absolute value and smaller than the maximum value of the absolute value of the noise data, so that V _max will not allow △ V to be a negative value and will not exceed the absolute value of the noise data maximum magnitude.

Step S4, calculating the difference △ V between the absolute mean value and the highest threshold value: ;

Step S5, dividing the difference ΔV evenly into M segments;

Step S6, compare the sampling noise data with the j segment minimum pulse amplitude threshold : if there is noise data greater than the minimum pulse amplitude threshold in the sampled data, then go to step S7, otherwise go to S8;

in, , j =0,2,3,... M -1;

Step S7, judging whether the duration t _j of the noise data greater than the minimum pulse amplitude threshold of the j segment is greater than the preset pulse duration T _j of the j segment: if it exceeds, it is judged that the data has pulse noise once, otherwise, it is judged that the segment Impulse noise does not appear;

in, , j =0,2,3,... M -1, t _max and t _min are respectively the maximum and minimum duration of an impulse noise;

More preferably, said step S7 also includes the following steps:

Step S71, if greater than the first If the noise data with the lowest pulse amplitude threshold of the segment is judged to have pulse noise, and the noise data duration t _j is much longer than the duration T _j , then this segment of noise data contains t _j / T _j pulses, j =0,2,3 ,... M -1;

Step S8, judging whether j is equal to M -1 (that is, judging whether the comparison of all segments is over): if yes, then end and return; otherwise, go to step S6 to enter the next segment and continue the comparison.

More preferably, said step S8, when it is judged that the comparison is over, further includes the following steps:

Step S81, sorting out the comparison results: if there is more than one segment where pulses appear, add up the pulse times of all segments where pulses appear to obtain all the pulse information of the entire segment of noise data.

The specific parameters are set to:

The sampling frequency f _s is preset as 100MHZ; the preset sampling point N is 100,000 points; the preset sampling time is 1ms; the highest amplitude of pulse noise is preset as V _max 0.21V, and the segment M =4.

As shown in Figure 2, a data acquisition device (TCD100) is used to collect PLC channel noise data, and the data is imported into the low-voltage power line communication (PLC) channel pulse noise detection method of the present invention for calculation to realize multi-pulse noise detection.

Figure 3 is the time-domain waveform diagram of the pulse detection in this example, the horizontal axis is the time (in ms) and the vertical axis is the pulse voltage (in mV);

Fig. 4 is a schematic diagram of the results of pulse detection.

The specific implementation of the present invention has been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned implementation, within the knowledge of those of ordinary skill in the art, it can also be made without departing from the gist of the present invention. Variations.

Claims (5)

1. A low-voltage power line communication channel pulse noise detection method based on amplitude and width, is characterized in that: the concrete steps of described method are as follows: Step S1, sampling the power line communication channel noise to obtain N sampling points d _i , i =0, 1, 2, 3,... N -1; Step S2, calculate the absolute value mean of N sampling noise data: , i =0,1,2,3,... N -1; Step S3, preset the maximum pulse amplitude threshold value V _max ; Step S4, calculate the difference △ V between the highest threshold value and the mean absolute value: ; Step S5, dividing the difference ΔV evenly into M segments; Step S6, compare the sampling noise data d _i with the lowest pulse amplitude threshold of the j segment : if there is noise data greater than the minimum pulse amplitude threshold in the sampled data, then go to step S7, otherwise go to S8; in, , j =0,1,2,3,... M -1; Step S7, judging whether the duration t _j of the noise data greater than the minimum pulse amplitude threshold of the j segment is greater than the preset pulse duration T _j of the j segment: if it exceeds, it is judged that the data has pulse noise once, otherwise, it is judged that the segment Impulse noise does not appear; in, , j =0,1,2,3,... M -1, t _max and t _min are respectively the maximum and minimum duration of an impulse noise; Step S8, judging whether j is equal to M -1: if yes, then end and return; otherwise, go to step S6 to enter the next segment to continue the comparison. 2. the low voltage power line communication channel impulse noise detection method based on amplitude and width according to claim 1, is characterized in that: The step S8, when it is judged that the comparison is over, further includes the following steps: Step S81, sorting out the comparison results: if there is more than one segment where pulses appear, add up the pulse times of all segments where pulses appear to obtain all the pulse information of the entire segment of noise data. 3. the low-voltage power line communication channel pulse noise detection method based on amplitude and width according to claim 2, characterized in that: in the step S1, the sampling frequency f _s for sampling the low-voltage power line communication channel noise satisfies Nyquis required by the special sampling theorem. 4. The low-voltage power line communication channel pulse noise detection method based on amplitude and width according to claim 2, characterized in that: in the step S3, the value of V _max is selected so that V _max is greater than the absolute mean value and less than the noise The maximum value of the absolute value of the data. 5. The low-voltage power line communication channel impulse noise detection method based on amplitude and width according to any one of claims 1 to 4, characterized in that: Said step S7 also includes the following steps: Step S71, if the noise data greater than the minimum pulse amplitude threshold of the jth segment is judged to have pulse noise, and the noise data duration t _j is much longer than the duration T _j , then this segment of noise data contains t _j / T _j pulses, j =0,1,2,3,... M -1.