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Method and apparatus for frequency estimation of undersampled signals based on pattern clustering and spectrum correction

A technology of signal frequency and under-sampling, which is applied in character and pattern recognition, computing, computer components, etc., can solve the problems of not being able to apply multi-frequency, high complexity, and low reconstruction accuracy, so as to reduce computational complexity and Hardware requirements, the effect of high measurement accuracy

Inactive Publication Date: 2019-02-05
TIANJIN UNIV
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  • Description
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Problems solved by technology

[0005] (1) Statistical cross-correlation operations will lead to large delays and high complexity [5,9] ;
[0006] (2) The recovery result is limited, because the traditional CRT can only provide MN possible reconstruction values, although the literature [10] proposed a 0.5-shift operation to double the resolution of the mutual prime spectrum analyzer, but its reconstruction accuracy is still low
However, all these improved CRT-based estimators [3,4,6,7,11-13] Can only handle frequency estimation of single-frequency undersampled waveforms, and cannot be applied to multi-frequency cases

Method used

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  • Method and apparatus for frequency estimation of undersampled signals based on pattern clustering and spectrum correction
  • Method and apparatus for frequency estimation of undersampled signals based on pattern clustering and spectrum correction
  • Method and apparatus for frequency estimation of undersampled signals based on pattern clustering and spectrum correction

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Embodiment 1

[0064] An embodiment of the present invention provides a method for estimating the frequency of an undersampled signal based on pattern clustering and spectrum correction, see figure 1 , the method includes the following steps:

[0065] 101: Perform N-point DFT plus a Hanning window on the sample sequence of the L-channel undersampled signal to obtain a DFT spectrum;

[0066] Among them, the L channel undersampling signal sample sequence is used by x 1 (n),...,x L (n) means that the DFT spectrum is represented by X 1 (k),...,X L (k) (k=0,...,N-1) represents. For any l-th spectrum (l=0,...,L), record the peak point of the DFT spectrum as k m,l ,m=1,...,M. The value of M is a positive integer.

[0067] 102: Perform spectrum and phase correction based on the ratio method on the DFT spectrum to obtain a corrected parameter set consisting of frequency, phase, and amplitude, and obtain a vector composed of corrected parameters;

[0068] Among them, the parameter group uses ...

Embodiment 2

[0078] In order to make the object of the present invention, technical scheme and advantage clearer, below in conjunction with specific mathematical formula, figure 1 The scheme in embodiment 1 is described in further detail, see the following description for details:

[0079] 1. CRT reconstruction model for single frequency estimation

[0080] For a single frequency signal x(t),

[0081]

[0082]Among them, a, θ 0 , f 0 Represents the magnitude, raw phase, and estimated frequency.

[0083] Estimating frequency f at low hardware cost 0 , the single-frequency signal x(t) needs to use L subsampling rates F 1 ,...,F L 0 For discretization, and the greatest common divisor N=gcd{f of the uniform undersampling rate is required s1 ,..., f sL}, so as to get the co-prime integer set Γ 1 ,...,Γ L :

[0084] Γ l =F l / N,l=1,...,L (4)

[0085] Thus, L sequences x of length N can be obtained l (n), l=1,...L,

[0086]

[0087] Among them, F l is the undersampling rate...

Embodiment 3

[0141] Combine below Figure 2-Figure 4 , and table 1 carries out feasibility verification to the scheme in embodiment 1 and 2, see the following description for details:

[0142] In this section, the estimator proposed by the embodiment of the present invention is used to process under-sampled multi-frequency complex-valued signals, as shown in formula (11), and M=4, L=2 and N=512, Γ are defined in the experiment 1 =3301,Γ 2 = 3307 (so F 1 =1.690112 Msamples / s, F 2 = 1.693184M samples / s).

[0143] For the multi-frequency case, there are M spectral peaks in the DFT spectrum, and due to undersampling, for the Mth frequency component, its spectral peak is in the DFT spectrum X 1 (k) and X 2 The position in (k) may be biased (eg figure 2 shown). For the same signal, the magnitude and phase parameters are paired, and the above features can be used to identify the corresponding peak positions of the same source on two ADC sample sequences. Meanwhile, in order to overcome t...

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Abstract

The invention discloses an under-sampled signal frequency estimation method and device based on pattern clustering and spectrum correction, The method comprises the following steps of: obtaining DFT spectrum by DFT with N points and Hanning window for L-channel undersampled signal sample sequence, performing spectrum and phase correction on the DFT spectrum based on ratio method, obtaining corrected parameter group composed of frequency, phase and amplitude, and obtaining vector composed of the corrected parameter combination; Selecting a desired peak index from a set of vectors for the firstpath independent vector of the m-th frequency component; According to the peak index of harmonic parameters, the pattern clustering is carried out, and the remainder after clustering is obtained. Frequency residue array is constructed by using residue, and it is brought into CRT model for reconstruction, and the estimated frequency value is obtained. The device comprises an analog-to-digital converter, a DSP chip, an output driver and a display module. The invention introduces a spectrum correction algorithm to improve the precision of frequency reconstruction, and uses pattern clustering to improve the robustness of the estimator to noise.

Description

technical field [0001] The present invention relates to the technical field of signal analysis and processing, in particular to performing under-sampling processing, spectrum correction, mode clustering and Chinese remainder theorem reconstruction on multi-frequency source signals received by observation, so as to realize multi-frequency source signals frequency estimates. Background technique [0002] Frequency estimation with multi-component signals is a research hotspot in the field of signal processing, and has been widely used in radar, wireless communication, electronic warfare and other fields. However undersampling (i.e. sampling rate f s Far less than twice the signal frequency f 0 ) has always been a difficult problem for high-precision frequency estimation, because the Nyquist theorem requires more than 2 sampling points to be collected in one signal cycle. As the signal frequency increases, the sampling rate must be increased accordingly, which will affect The...

Claims

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Application Information

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IPC IPC(8): G06K9/00G06K9/62
CPCG06F2218/14G06F18/23
Inventor 黄翔东徐婧文
Owner TIANJIN UNIV
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