CN111355514B - Spread spectrum detection method for direct spread spectrum signal - Google Patents

Spread spectrum detection method for direct spread spectrum signal Download PDF

Info

Publication number
CN111355514B
CN111355514B CN202010304886.4A CN202010304886A CN111355514B CN 111355514 B CN111355514 B CN 111355514B CN 202010304886 A CN202010304886 A CN 202010304886A CN 111355514 B CN111355514 B CN 111355514B
Authority
CN
China
Prior art keywords
spectrum
threshold
data
spread spectrum
direct
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010304886.4A
Other languages
Chinese (zh)
Other versions
CN111355514A (en
Inventor
刘泷
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NANJING SINOVATIO TECHNOLOGY CO LTD
Original Assignee
NANJING SINOVATIO TECHNOLOGY CO LTD
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NANJING SINOVATIO TECHNOLOGY CO LTD filed Critical NANJING SINOVATIO TECHNOLOGY CO LTD
Priority to CN202010304886.4A priority Critical patent/CN111355514B/en
Publication of CN111355514A publication Critical patent/CN111355514A/en
Application granted granted Critical
Publication of CN111355514B publication Critical patent/CN111355514B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

The invention discloses a spread spectrum detection method of a direct spread spectrum signal, thereby providing a simple and effective spread spectrum detection method which is simultaneously suitable for long codes and short codes, and solving the problems of long scrambling period, large data volume and difficult detection of the direct spread spectrum signal. According to the characteristic that a direct sequence spread spectrum signal has double code rates of a baseband code rate and a spread spectrum code rate, sampling data is subjected to low-pass filtering and then extracted by N times, the calculated power spectrum is required to be lower than a threshold, namely only the low-frequency part of the original data is reserved, and otherwise, filtering and extraction are continued; then, calculating an envelope spectrum and a threshold by adopting a sectional average mode on the extracted data; and finally, detecting and counting the effective peak points which pass the threshold in the envelope spectrum, if the count is more than 1, namely a baseband code rate spectral line exists, considering that the direct spread signal exists in the sampled data, and if not, considering that the direct spread signal does not exist in the sampled data.

Description

Spread spectrum detection method for direct spread spectrum signal
Technical Field
The invention relates to the field of signal detection and the field of spread spectrum modulation identification, in particular to a spread spectrum detection method for a direct spread spectrum signal.
Background
The spread spectrum communication technology has the characteristics of strong concealment, interception resistance, noise and interference resistance, and is widely applied along with the development of the wireless broadband digital communication technology. The requirement for spread spectrum signal detection is increasingly urgent, and spread spectrum signal detection has important significance for abnormal signal discovery, environment safety detection, digital countermeasure and the like.
Taking CDMA2000 uplink signal as an example for explanation, the CDMA2000 uplink signal is a typical long code direct sequence spread spectrum signal, wherein the long code period is 41 days, 10 hours, 12 minutes, and 19.4 seconds. If the detection is carried out by adopting a cepstrum, a quadratic spectrum and other modes, data of more than 82 days needs to be continuously acquired for calculation, and in actual operation, the required time of 82 days is too long, so that the application feasibility is not realized.
Therefore, a new technical solution is needed to solve the above problems.
Disclosure of Invention
The invention aims to: the spread spectrum detection method of the direct spread spectrum signal is provided, is simultaneously suitable for the spread spectrum detection method of the long code and the short code, and solves the problems that the scrambling code period of the direct spread spectrum signal is long, the data volume is large, and the detection is difficult.
In order to achieve the purpose, the invention can adopt the following technical scheme:
the spread spectrum detection method of the direct spread spectrum signal is characterized by comprising the following steps:
1) sampling the direct spread signal data at a sampling rate fsObtaining zero intermediate frequency sampling data { x (n) ═ 1,2, … … }; then, FFT (fast Fourier transform) is carried out on the x (n) sequence in a segmented average mode to obtain a power spectrum, and the power spectrum { p (n) }, wherein n is 1,2,3, … … and M;
2) calculating an x-dB bandwidth BW for the power spectrum { p (n) ═ 1,2,3, … …, M };
3) according to the sampling rate fsAnd bandwidth BW, calculating an extraction multiple N;
4) according to the extraction multiple N, firstly, the sampling data { x (N) }, N ═ 1,2, … … } is convoluted by a low-pass filter with the coefficient h (N), the convolution calculation result data { y (N) }, N ═ 1,2, … … } is output, and the passband bandwidth of the low-pass filter is equal to
Figure BDA0002455411860000011
Then extracting the convolution calculation result data by N times to obtain extracted data
Figure BDA0002455411860000012
5) To pair
Figure BDA0002455411860000021
The sequence is subjected to FFT conversion in a segmented average mode to obtain a power spectrum
Figure BDA0002455411860000022
6) For power spectrum
Figure BDA0002455411860000023
Calculating the mean value to obtain a threshold1Traversing all points in the power spectrum, searching whether a point which passes a threshold exists, if the active power value is higher than the point of the threshold, making N be 2 x N, and executing the step 4); otherwise, executing step 7);
7) to pair
Figure BDA0002455411860000024
Envelope of sequence calculation
Figure BDA0002455411860000025
Then FFT transform is carried out by adopting a sectional average mode to obtain an envelope spectrum
Figure BDA0002455411860000026
8) For envelope spectrum
Figure BDA0002455411860000027
Calculating the mean value to obtain a threshold2Traversing all points in the envelope spectrum, searching whether a point which passes a threshold and is a valid peak exists, counting the point as c, and if the point is found, adding 1 to the value of c;
9) judging the value of c, if the value is larger than 1, sampling data { x (n) }, wherein n is 1,2, … …, and is a direct spread spectrum signal; otherwise { x (n) ═ 1,2, … … } is an indirect spread spectrum signal.
Has the advantages that: according to the detection method provided by the invention, according to the characteristic that a direct sequence spread spectrum signal has double code rates of a baseband code rate and a spread spectrum code rate, sampling data is subjected to low-pass filtering and then N times of extraction, the calculated power spectrum is required to be lower than a threshold, namely only the low-frequency part of the original data is reserved, and otherwise, filtering and extraction are continued; then, calculating an envelope spectrum and a threshold by adopting a sectional average mode on the extracted data; and finally, detecting and counting the effective peak points which pass the threshold in the envelope spectrum, if the count is more than 1, namely a baseband code rate spectral line exists, considering that the direct spread signal exists in the sampled data, and if not, considering that the direct spread signal does not exist in the sampled data. The detection method is simple and convenient, is simultaneously suitable for the spread spectrum detection method of long codes and short codes, and solves the problems of long code direct spread spectrum signal scrambling code period, large data volume and difficult detection. The method can also solve the problems that the short code direct sequence spread spectrum signal period is uncertain, and the processing time is prolonged if the longer data is used for calculating larger calculation amount caused by secondary spectrum and the like, thereby effectively improving the detection efficiency of the direct sequence spread spectrum signal including the short code.
Further, performing FFT conversion to solve a power spectrum or an envelope spectrum in a segmented averaging manner in the steps 1), 5) and 7), that is, extracting L segments of data from the input data, wherein the length of each segment of data is M, performing FFT conversion with the length of M on each segment of data, then calculating power values, and finally accumulating corresponding positions to calculate an average.
Further, in the step 3), the method for calculating the extraction multiple N is that N satisfies
Figure BDA0002455411860000028
And can trim fsIs the smallest integer of (a).
Further, in step 6), a threshold is calculated
Figure BDA0002455411860000029
Further, in step 8), a threshold is calculated
Figure BDA0002455411860000031
Further, in step 8, the effective peak point has the following three conditions:
1) envelope power value
Figure BDA0002455411860000032
Above a threshold, i.e. satisfy
Figure BDA0002455411860000033
2) Definition of
Figure BDA0002455411860000034
The value higher than the left and right is the peak point, namely the peak point is satisfied
Figure BDA0002455411860000035
3) The adjacent wave peak points need to exist below the threshold2Point (2) of (c).
Further, the direct sequence spread spectrum signal is a long code direct sequence spread spectrum signal or a short code direct sequence spread spectrum signal. x-dB is chosen to be 10 dB.
Drawings
Fig. 1 is a flow chart of spread spectrum detection of direct sequence spread spectrum signals according to the present invention.
FIG. 2 is fs＝2.5*106CDMA2000 uplink signal power spectrum at sampling rate.
Fig. 3 shows a sampled CDMA2000 uplink signal 500 x 103And carrying out HZ low-pass filtering and then extracting N to 5 times of the power spectrogram and the threshold.
Fig. 4 shows a sampled CDMA2000 uplink signal 500 x 103And carrying out HZ low-pass filtering and N-time extraction to obtain an envelope spectrogram and a threshold.
FIG. 5 is fs＝2.5*106CDMA2000 downlink signal power spectrogram at sampling rate.
Fig. 6 shows a sampled CDMA2000 downlink signal 500 x 103And carrying out HZ low-pass filtering and then extracting N to 5 times of the power spectrogram and the threshold.
Fig. 7 shows a sampled CDMA2000 downlink signal 500 x 103And carrying out HZ low-pass filtering and N-time extraction to obtain an envelope spectrogram and a threshold.
Detailed Description
The spread spectrum detection method of the direct spread spectrum signal provided by the invention is applicable to both the spread spectrum detection of the long code direct spread spectrum signal and the spread spectrum detection of the short code direct spread spectrum signal, and two embodiments are provided below for respective description.
Example one
Please refer to fig. 1 to 4.
In the following, the CDMA2000 uplink signal is taken as an example for description, and the step of detecting the CDMA2000 uplink signal by using the direct spread spectrum detection method provided by the present invention includes:
step 1, triggering the CDMA2000 terminal to generate continuous uplink service data, and collecting the data with 2.5 x 106The sampling rate of (a) is 8 seconds of zero intermediate frequency data, which is marked as { x (n) }, n is 1,2, … …;
step 2, sequentially extracting L (default 100) segments of data from the sampling data { x (n) }, where n is 1,2, … …, where the length of each segment of data is M (default 32768), respectively performing FFT (fast Fourier transform) on each segment of data to obtain power values, accumulating the corresponding positions of the L segments of power values to obtain an average, thereby obtaining a power spectrum { p (n) }, where n is 1,2,3, … …, M }, and then calculating a "10-dB bandwidth" corresponding to the power spectrum, so as to obtain BW is 1.23 × 106HZ；
Step 3, calculating an extraction multiple N: so that N satisfies
Figure BDA0002455411860000041
And N is fsIf the minimum integer of (a) is greater than (b), then let N be 5;
step 4, according to the extraction multiple N being 5, and fs＝2.5*106Then the pass band is designed to be
Figure BDA0002455411860000042
The low-pass filter of (2), whose coefficient is h (n), convolves the sample data { x (n) ═ 1,2, … … } with the filter coefficient, and outputs { y (n) ═ 1,2, … … };
and step 5, performing N (N is 5) times of extraction on the data { y (N), N is 1,2 and … … }, and reducing the sampling rate by N times to obtain an output sequence
Figure BDA0002455411860000043
Namely, it is
Figure BDA0002455411860000044
Step 6, extracting the data
Figure BDA0002455411860000045
FFT transform is carried out by adopting a sectional average mode to calculate a power spectrum to obtain
Figure BDA0002455411860000046
The default value of the FFT transformation length M is 32768, the default value of the segment number L is 100, and then the average value of the power spectrum is calculated to obtain 29.6604dB, so that the threshold is obtained1＝39.6604dB；
Step 7, traversing the power spectrum
Figure BDA0002455411860000047
All points in the table, not above the threshold1So step 8 is performed; otherwise, the extracted data still has a power spectrum, and after N is made to be N x 2, the step 4 is executed;
step (ii) of8. For extracted data
Figure BDA0002455411860000048
Adopting a segmented average mode to carry out FFT (fast Fourier transform) to calculate an envelope spectrum to obtain
Figure BDA0002455411860000049
The FFT length M is 32768, the default value of the segment number L is 100, and then the average value of the envelope spectrum is calculated to obtain 21.3917dB, so that the threshold is obtained2＝31.2917dB；
Step 9, traversing the envelope spectrum
Figure BDA0002455411860000051
All points in the table, above the threshold2And 3 effective peak points in total, i.e. c is 3>1, and thus, the sample data { x (n) ═ 1,2, … … } is judged to be a direct spread spectrum signal.
The comparison of the test results of the above examples with the prior art shows that: in the prior art, the CDMA2000 uplink signal is a typical long code direct sequence spread spectrum signal, wherein the long code period is 41 days, 10 hours, 12 minutes, and 19.4 seconds. If the detection is performed by adopting the modes of cepstrum, quadratic spectrum and the like, data of more than 82 days (namely data of two scrambling code periods) needs to be continuously acquired for calculation, and the calculation is hardly feasible; the detection method of the invention can successfully detect the spread spectrum modulation signal, and only 8 seconds of data are collected for detection, thereby greatly improving the detection efficiency.
Example two
Please refer to fig. 5 to 7.
The following description will be made by taking CDMA2000 downlink signals as an example for direct sequence spread spectrum detection: the biggest difference from the uplink signal spread spectrum is that the downlink signal is a short code direct spread spectrum signal, and the scrambling code period of the downlink signal is 26.67 ms; the scrambling code rates of the uplink and downlink signals are both 1.2288 x 106HZ, spectral bandwidth is 1.23 x 106HZ, so the same detection procedure as in the first embodiment is also performed for CDMA2000 downlink short code direct sequence spread spectrum signals:
step 1, configuring local oscillation frequency point of acquisition equipment as CDMA2000 downlink signal frequency point 878.49 x 106The collecting apparatus is 2.5 x 106The sampling rate of (a) is 8 seconds of zero intermediate frequency data, which is marked as { x (n) }, n is 1,2, … …;
step 2, sequentially extracting L (default 100) segments of data from the sampling data { x (n) }, where n is 1,2, … …, where the length of each segment of data is M (default 32768), respectively performing FFT (fast Fourier transform) on each segment of data to obtain power values, accumulating the corresponding positions of the L segments of power values to obtain an average, thereby obtaining a power spectrum { p (n) }, where n is 1,2,3, … …, M }, and then calculating a 10-dB bandwidth corresponding to the power spectrum to obtain BW is 1.23 × 106HZ；
Step 3, calculating the extraction multiple by the same method to obtain N which is 5;
step 4, similarly, performing convolution calculation on the sampled data { x (n) = 1,2, … … } and the filter coefficient h (n), and outputting { y (n) }, wherein n is 1,2, … … };
and step 5, performing N (N is 5) times of extraction on the data { y (N), N is 1,2 and … … }, and reducing the sampling rate by N times to obtain an output sequence
Figure BDA0002455411860000052
Namely, it is
Figure BDA0002455411860000053
Step 6, extracting the data
Figure BDA0002455411860000054
FFT transform is carried out by adopting a sectional average mode to calculate a power spectrum to obtain
Figure BDA0002455411860000061
The default value of the FFT transformation length M is 32768, the default value of the segment number L is 100, and then the power spectrum is calculated to be-21.2930 dB, so that the threshold is obtained1＝-11.2930dB；
Step 7, traversing the power spectrum
Figure BDA0002455411860000062
All points in the table, not above the threshold1So step 8 is performed;
step (ii) of8. For extracted data
Figure BDA0002455411860000063
Adopting a segmented average mode to carry out FFT (fast Fourier transform) to calculate an envelope spectrum to obtain
Figure BDA0002455411860000064
The FFT length M is 32768, the default value of the segment number L is 100, and then the envelope spectrums are calculated to be 27.6701dB, so that the threshold is obtained2＝-17.6701dB；
Step 9, traversing the envelope spectrum
Figure BDA0002455411860000065
All points in the table, above the threshold2And 9 significant peak points are determined, and the sample data { x (n) ═ 1,2, … … } is determined to be a direct spread spectrum signal. In addition, under the condition that the spreading order (64 orders) of the CDMA2000 downlink common physical channel is known, the effective peak point positions in the envelope spectrum can be further verified to respectively correspond to the baseband code rate before spreading of 19.2 x 103And multiples thereof.
The comparison of the test results of the above examples with the prior art shows that: the short code cycle period of a short code direct spread signal such as a CDMA2000 downlink signal can be unknown, i.e., any short code cycle period can be adapted without considering the relationship between the duration of the sampled data and the short code cycle period. Generally, the cycle periods of scrambling codes of different direct-spread signals are different, the existing calculation modes such as secondary spectrum are adopted, in order to detect as many short-code direct-spread signals as possible, the data processing needs to be as long as possible, and the sampling data corresponding to the time length more than twice as long as the maximum short-code cycle period needs to be met, so that the increase of the calculated amount and the reduction of the detection efficiency are brought.

Claims (7)

1. A spread spectrum detection method of a direct spread spectrum signal is characterized by comprising the following steps:
1) sampling the direct spread signal data at a sampling rate fsObtaining zero intermediate frequency sampling data x (n), wherein n is 1,2, … …; then to the sequence of x (n)Performing FFT to obtain a power spectrum by adopting a sectional averaging mode, and obtaining a power spectrum p (n), wherein n is 1,2,3, … … and M;
2) calculating an x-dB bandwidth BW for the power spectrum p (n), n ═ 1,2,3, … …, M; the x-dB is selected to be 10 dB;
3) according to the sampling rate fsAnd bandwidth BW, calculating an extraction multiple N;
4) according to the extraction multiple N, firstly, the sampling data x (N) is given, and N is 1,2 and … …; performing convolution calculation through a low-pass filter with the coefficient h (n), and outputting convolution calculation result data y (n), wherein n is 1,2 and … …; the passband bandwidth of the low pass filter is
Figure FDA0003207837900000011
Then extracting the convolution calculation result data by N times to obtain extracted data
Figure FDA0003207837900000012
5) To pair
Figure FDA0003207837900000013
… … sequence is processed by FFT to obtain power spectrum by means of segment averaging
Figure FDA0003207837900000014
6) For power spectrum
Figure FDA0003207837900000015
… …, M calculates the mean value, thus obtaining the threshold1Traversing all points in the power spectrum, searching whether a point which passes a threshold exists, if the active power value is higher than the point of the threshold, making N be 2 x N, and executing the step 4); otherwise, executing step 7);
7) to pair
Figure FDA0003207837900000016
… … envelope calculation of sequence
Figure FDA0003207837900000017
… …, and performing FFT to obtain envelope spectrum by using a segmented average method
Figure FDA0003207837900000018
……，M；
8) For envelope spectrum
Figure FDA0003207837900000019
… …, M calculates the mean value, thus obtaining the threshold2Traversing all points in the envelope spectrum to find whether threshold is exceeded2And is the point of the effective peak, threshold for threshold crossing2And the count of the points which are effective wave crests is recorded as c, if the threshold is found to exist2And the point which is the effective peak adds 1 to the value of c;
9) judging the value of c, if the value is larger than 1, sampling data x (n), wherein n is 1,2 and … … are direct spread spectrum signals; otherwise, x (n), n ═ 1,2, … … is an indirect spread spectrum signal.
2. The direct sequence spread spectrum detection method according to claim 1, wherein the step 1), the step 5) and the step 7) are performed with FFT conversion for power spectrum or envelope spectrum by means of segmented averaging, i.e., L segments of data are extracted from the input data, each segment of data has a length of M, each segment of data is performed with FFT conversion with a length of M, then power values are respectively obtained, and finally the L segments of power values are accumulated at corresponding positions for averaging.
3. The spread spectrum detection method of claim 1, wherein in step 3), the decimation factor N is calculated so that N satisfies the requirement
Figure FDA0003207837900000021
And can trim fsIs the smallest integer of (a).
4. The direct sequence spread spectrum detection method according to claim 1,characterized in that, in step 6), the threshold is calculated
Figure FDA0003207837900000022
5. The spread-spectrum detection method of claim 1, wherein in step 8), the threshold is calculated
Figure FDA0003207837900000023
6. The direct spread spectrum detection method according to claim 1 or 5, wherein the effective peak point has the following three conditions in step 8:
1) envelope power value
Figure FDA0003207837900000024
Above threshold2I.e. satisfy
Figure FDA0003207837900000025
2) Definition of
Figure FDA0003207837900000026
The value higher than the left and right is the peak point, namely the peak point is satisfied
Figure FDA0003207837900000027
3) The adjacent wave peak points need to exist below the threshold2Point (2) of (c).
7. The direct-spread signal spectrum detection method according to claim 1, wherein the direct-spread signal is a long-code direct-spread signal or a short-code direct-spread signal.
CN202010304886.4A 2020-04-17 2020-04-17 Spread spectrum detection method for direct spread spectrum signal Active CN111355514B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010304886.4A CN111355514B (en) 2020-04-17 2020-04-17 Spread spectrum detection method for direct spread spectrum signal

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010304886.4A CN111355514B (en) 2020-04-17 2020-04-17 Spread spectrum detection method for direct spread spectrum signal

Publications (2)

Publication Number Publication Date
CN111355514A CN111355514A (en) 2020-06-30
CN111355514B true CN111355514B (en) 2021-12-28

Family

ID=71197734

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010304886.4A Active CN111355514B (en) 2020-04-17 2020-04-17 Spread spectrum detection method for direct spread spectrum signal

Country Status (1)

Country Link
CN (1) CN111355514B (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1529433A (en) * 2003-10-10 2004-09-15 清华大学 Low-complexity portion parallel transmission method for multi-carrier direct spread spectrum CDMA system
CN101951273A (en) * 2010-09-14 2011-01-19 中国科学院上海微***与信息技术研究所 Long code word acquisition method for wireless sensor network
CN104158559A (en) * 2014-07-31 2014-11-19 上海航天电子通讯设备研究所 Long code fast-acquisition method on basis of direct spread system
CN108337015A (en) * 2017-12-26 2018-07-27 武汉船舶通信研究所（中国船舶重工集团公司第七二二研究所） A kind of pseudo-code method for catching and device
CN109474306A (en) * 2018-09-20 2019-03-15 中国人民解放军63653部队 A kind of detection decision method based on direct sequence signal capture

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1529433A (en) * 2003-10-10 2004-09-15 清华大学 Low-complexity portion parallel transmission method for multi-carrier direct spread spectrum CDMA system
CN101951273A (en) * 2010-09-14 2011-01-19 中国科学院上海微***与信息技术研究所 Long code word acquisition method for wireless sensor network
CN104158559A (en) * 2014-07-31 2014-11-19 上海航天电子通讯设备研究所 Long code fast-acquisition method on basis of direct spread system
CN108337015A (en) * 2017-12-26 2018-07-27 武汉船舶通信研究所（中国船舶重工集团公司第七二二研究所） A kind of pseudo-code method for catching and device
CN109474306A (en) * 2018-09-20 2019-03-15 中国人民解放军63653部队 A kind of detection decision method based on direct sequence signal capture

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
直接序列扩频信号的检测方法研究;蔡晓哲;《中国优秀硕士学位论文全文数据库 信息科技辑》;20070531;I136-302 *
直接扩频信号的检测与估计;赵倩;《中国优秀硕士学位论文全文数据库 信息科技辑》;20091130;I136-202 *

Also Published As

Publication number Publication date
CN111355514A (en) 2020-06-30

Similar Documents

Publication Publication Date Title
CN110224721B (en) Method and receiver for processing an analog signal from a transmission channel
WO2006092093A1 (en) Method and device for suppressing narrowband interference
CN107612865B (en) Signal noise reduction method applied to low-voltage power line carrier communication
CN109257068B (en) Adaptive filtering method for power line communication signals
CN108880621B (en) Adaptive filtering method for power line communication signals
CN102904604A (en) Narrow-band interference suppression method and device
CN113341378B (en) Self-adaptive channelized receiving method based on frequency spectrum differential entropy detection
KR101613731B1 (en) Apparatus and method for extracting reference cancellation pulse in multi-carrier system and peak cancellation crest factor reduction system for the same
CN106656372B (en) Frequency band interference detection method of frequency hopping system
CN111355514B (en) Spread spectrum detection method for direct spread spectrum signal
EP1865639A1 (en) A method and an apparatus for eliminating the narrow-band interference in the spread spectrum system
CN102421163A (en) Method and device for sequencing frequency points of LTE (Long Term Evolution) system
CN109039379B (en) Power line communication signal filtering method
CN110784245B (en) Spread spectrum code synchronization method and system based on cumulative power correlation
CN105245247A (en) Adaptive threshold controller and control method, direct sequence spread spectrum signal detection method and circuit
CN109586763B (en) Denoising method and denoising system for spread spectrum signal in electronic communication system
Schlechter et al. Overview on blockerdetection in LTE systems
CN215177919U (en) Transformer vibration state monitoring device
CN112865882B (en) Anti-frequency offset DMR interphone signal rapid identification method
CN111510173B (en) Multichannel radio station received signal separation method and device and analog radio station host
Mahesh et al. Reconfigurable discrete Fourier transform filter banks for variable resolution spectrum sensing
CN108880620B (en) Power line communication signal reconstruction method
Cheng et al. An efficient wide-band signal detection and extraction method
EP3742620A1 (en) Radio communication system and interference suppression method
CN116032310B (en) Signal self-adaptive detection reconstruction method based on channelized filtering

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant