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A mutual prime spectrum analysis method and device for eliminating false peaks and spectral leakage effects

An analysis method, the technology of mutual prime spectrum, applied in the field of digital signal processing, can solve the problems of false peaks, false alarms, and inaccurate cut-off frequency positions, and achieve the effect of improving frequency resolution

Inactive Publication Date: 2017-10-27
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, the method proposed in literature [11] also has its own insurmountable defects. In order to complete the spectrum estimation, two low-pass prototype filters need to be designed. The passband cut-off frequencies are π / M and π / N (M and N are mutually Integer), but because the ideal filter (the transition band is 0, the cutoff frequency accurately falls on the desired point) is impossible to realize (the actual filter always has a transition band, the cutoff frequency position is not accurate), so for the filter The signal component in the middle of the passband (that is, the signal frequency is close to iΔω, i∈Z + , Δω=2π / (MN)), the mutual prime spectrum analysis method proposed in [11] can identify it well; , i∈Z + ), due to the interaction between the adjacent sidebands of the non-ideal sub-filter, the spectral analysis results will leak in adjacent positions, and false peaks will appear in other positions, thus affecting the final signal frequency identification, especially the phenomenon of false peaks The existence of , seriously affects the readability of the mutual prime spectrum, and will cause false alarms in military applications
Due to the complexity of real signals, this situation is likely to occur in large numbers, seriously affecting the performance of spectrum estimation
Therefore, in view of the false peaks and spectral leakage problems caused by the unrealization of the ideal filter in the cross-prime spectrum analyzer proposed in literature [11], it is urgent to make necessary improvements to its cross-prime spectrum analysis structure, and to improve its spectrum analysis algorithm. optimization

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  • A mutual prime spectrum analysis method and device for eliminating false peaks and spectral leakage effects
  • A mutual prime spectrum analysis method and device for eliminating false peaks and spectral leakage effects
  • A mutual prime spectrum analysis method and device for eliminating false peaks and spectral leakage effects

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Embodiment 2

[0068] This embodiment 2 introduces the steps in embodiment 1 in detail in combination with the accompanying drawings and specific calculation formulas, see the following description for details:

[0069] 201: signal mutual prime perception processing;

[0070] Since the mutual prime spectrum sensing of multi-frequency signals can finally be decomposed into multiple single-frequency signal mutual prime spectrum sensing for processing separately. Therefore, first with the single-frequency signal As an example, to analyze the process of the signal passing through each node in the mutual prime spectrum analysis, and then extend it to the multi-frequency situation.

[0071] (1) Analysis of the mutual prime spectrum perception signal process of the direct pathway;

[0072] single frequency signal in, a 0 is the signal amplitude, f 0 is the normalized frequency, f 0 =(m+δ)Δf, Δf=1 / (MN), m∈[0, MN-1), δ is the fractional frequency offset (-0.5≤δ0 is the initial phase.

[0073...

Embodiment 3

[0139] (1) Single spectrum leakage suppression experiment

[0140] Experiment 1

[0141] Set two mutually prime integers M=5, N=4, single-frequency signal x(t)=1.2exp(j2π·10.51t), δ=-0.49, ideal sampling rate F s =MN=20Hz (corresponding sampling interval T=1 / F s =1 / MN), frequency resolution Δf=F s / MN=1Hz, then according to the mutual prime spectrum analysis method, the actual undersampling values ​​of the two channels are respectively f s1 =1 / NT=M=5Hz, f s2 =1 / MT=N=4Hz, both of which are far lower than the signal frequency of 10.51Hz. Design a two-way prototype low-pass filter using the Remez method with a length of 121, Figure 7 (a)~7(e) give the original mutual prime spectrum translational coprime spectrum indicator ρ 1 (i), indicator ρ 2 (i) and the mutual prime spectrum Y(j) whose resolution is doubled by the improved resolution obtained by the present invention.

[0142] Figure 7 (a) is the spectrum output of the original mutual prime spectrum estimator. S...

Embodiment 4

[0148] A mutual prime spectrum analysis device that eliminates false peaks and spectral leakage effects, see Figure 9 , the device includes: a digital signal processor, and an output drive and display circuit,

[0149] The digital signal processor is used to perform cross-correlation scan evaluation on the output sequence after the discrete Fourier transform to obtain the original spectrum sequence and the shifted spectrum sequence; the shifted spectrum sequence shifts to the left by one unit, and the original spectrum sequence Multiply with the corresponding elements of the frequency-shifted sequence to obtain the first frequency indication sequence; multiply the original spectrum sequence and the corresponding elements of the shifted spectrum sequence to obtain the second frequency indication sequence; combine the first frequency indication sequence and the second frequency indication sequence The two frequency indication sequences are input to the logic decision device, an...

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Abstract

The invention discloses a co-prime spectrum analysis method and apparatus for eliminating pseudo peak and spectrum leakage effects. The co-prime spectrum analysis method comprises the following steps: carrying out cross-correlation scanning evaluation on an output sequence obtained after Discrete Fourier Transform to obtain an original frequency spectrum sequence and a frequency spectrum sequence after translation; shifting the frequency of the frequency spectrum sequence after the translation to the left by one unit, and multiplying the original frequency spectrum sequence by corresponding elements of the sequence after a frequency shift to obtain a first frequency indication sequence; multiplying the original frequency spectrum sequence by corresponding elements of the frequency spectrum sequence after the translation to obtain a second frequency indication sequence; and inputting the first frequency indication sequence and the second frequency indication sequence into a logic determinator, and according to the corresponding relation between the same frequencies in the two frequency indication sequences, obtaining the position of a normalization frequency in a frequency spectrum graph. The apparatus comprises a digital signal processor and an output driving and display circuit. According to the invention, the pseudo peak effect and the spectrum leakage effect are completely eliminated, a given frequency is accurately identified, and the frequency resolution is improved.

Description

technical field [0001] The invention relates to the field of digital signal processing, in particular to a mutual prime spectrum analysis method and device for eliminating false peaks and spectral leakage effects, and specifically to signal undersampling, polyphase filtering process, signal correlation and power spectral density estimation. Background technique [0002] Spectrum estimation is related to many actual physical quantity measurements (such as radar wind speed measurement in atmospheric dynamics research [1] , Speed ​​measurement in vibration analysis [2] etc.) closely related signal processing methods [3,4] , is widely used in various disciplines such as electronics, electricity and automation, and is the basic problem of digital signal processing. Only when the traditional spectrum estimation satisfies Shannon sampling theorem (that is, at least two samples are required to be collected in a signal cycle), the signal will not be distorted, and it is possible to...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R23/163
Inventor 黄翔东闫子阳冼弘宇
Owner TIANJIN UNIV