Improved phase difference frequency estimation method

A technology of frequency estimation and phase difference, applied in the field of digital signal processing, to achieve the effects of wide application prospects, low computational complexity, and strong anti-interference ability

Active Publication Date: 2017-10-31
TIANJIN UNIV
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Problems solved by technology

However, there is still room for improvement in the estimation accuracy of the classic apFFT/FFT phase difference method, and its RMSE curve still has a certain distance from the Cramer-Ra

Method used

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  • Improved phase difference frequency estimation method

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Embodiment 1

[0063] Set the complex signal x(n)=exp[j(ω 0 n+θ 0 )], -N+1≤n≤N-1, where N=32, ω 0 =(k * +δ)Δω,k * = 3, θ 0 = π / 3. In order to study the influence of frequency offset estimation δ on the estimation accuracy, we let δ take 0, 0.1, 0.4 respectively. Such as Figure 4 As shown, 4(a) gives the normalized double-window apFFT amplitude spectrum (w obtained by convolution of two Hamming windows c ), 4(b) gives the normalized FFT amplitude spectrum with Hamming window. Such as Figure 5 As shown, 5(a) gives the normalized windowless apFFT amplitude spectrum, and 5(b) gives the normalized windowless FFT amplitude spectrum. Table 1 lists the spectral peak amplitudes under different windowing conditions.

[0064] Table 1

[0065]

[0066] pass Figure 4 , Figure 5 And Table 1, we can summarize two rules:

[0067] (1) Regardless of the value of the frequency offset estimation δ, the peak spectrum amplitude of the dual-window apFFT|Y(k * )| and windowed FFT peak spectral...

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Abstract

The invention discloses an improved phase difference frequency estimation method. The method comprises: (2N-1) samples are inputted, windowless full-phase fast fourier transform is carried out on the samples to obtain a frequency spectrum Y(k), and N points are selected from the samples to carry out windowless full-phase fast fourier transform to obtain a frequency spectrum X(k); searching is carried out on the X(k) and the Y(k) to obtain a spectral peak location, spectral peak phases phiX(k<*>) and phiY(k<*>), a difference value delta phi~, phase adjustment is carried out to obtain delta phi, and dividing is carried out by tau=(N-1)/2 to obtain a frequency offset estimation value delta^1; |delta^1| is larger than or equal to xi, a sequence s(n)=exp(-j2pidelta^1n/N), time-domain modulation is carried out on the samples to obtain a frequency offset estimation value delta^<*>1, the delta^<*>1 is added to a delta^2 to obtain a frequency offset estimation value delta^; the |delta^1| is larger than or equal to 1 and is less than xi and the frequency offset estimation value delta^ is equal to delta^1; and the delta^ is substituted into a formula: f^0=(k<*>+delta^)/N to calculate a frequency offset estimation value. With introduction of frequency shift compensation measures, a solution measure to phase difference integer ambiguity is put forward, so that practicability is enhanced.

Description

technical field [0001] The invention relates to the field of digital signal processing, and more specifically relates to an improved phase difference frequency estimation method. Background technique [0002] Frequency estimation is an important part of digital signal processing, especially the frequency estimation of signals containing Gaussian white noise has always been a classic subject of signal processing. Frequency estimation has important research value not only in theory but also in practical applications (such as many Puller effect detection [1] , array direction of arrival estimation [2] , Speed ​​measurement in vibration analysis [3] etc. can be transformed into a frequency estimation problem). Since FFT (Fast Fourier Transform, Fast Fourier Transform) has the advantage of high computing efficiency, frequency estimation based on FFT has been a long-standing research topic in the academic circle. [0003] At present, frequency estimation mainly includes interp...

Claims

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Application Information

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IPC IPC(8): G01R23/02G01R23/16
CPCG01R23/02G01R23/16
Inventor 黄翔东王越冬
Owner TIANJIN UNIV
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