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A High-Precision Frequency Parameter Estimation Method Based on Time Shift and Phase Difference

A parameter estimation and phase difference technology, applied in the field of signal processing, can solve the problems of reduced calibration accuracy and not applicable to all frequencies, and achieve good anti-noise performance

Active Publication Date: 2019-11-15
CHONGQING UNIV OF POSTS & TELECOMM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the current MBTS method also has the following disadvantages: 1. When the translation coefficient M / N≥1, the current method is not suitable for all frequencies; 2. When two frequencies are very close (s a = ns 1 (n∈z + ), s a =s 2 -s 1 ), the correction accuracy of the current method is reduced

Method used

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  • A High-Precision Frequency Parameter Estimation Method Based on Time Shift and Phase Difference
  • A High-Precision Frequency Parameter Estimation Method Based on Time Shift and Phase Difference
  • A High-Precision Frequency Parameter Estimation Method Based on Time Shift and Phase Difference

Examples

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example 1

[0137] In practical engineering applications, signals are often disturbed by noise. In order to evaluate the impact of noise on the improved algorithm, the theoretical signal with additive Gaussian white noise is given by formula (1). Amplitude A 0 Set to 1, the sampling frequency is 256Hz, and the total data length is 256 points, so the frequency resolution is 1Hz. The frequency changes with a step distance of 0.1 within the interval -0.5 to 0.5. For each frequency step, the phase is scanned in the range -π~π with a step distance of π / 36. The signal-to-noise ratio (SNR) changes with a step distance of 5dB within the range of 0dB to 40dB. The root mean square error (RMSE) is used to evaluate the improved algorithm, and it is compared with the Cramereau lower bound (CRLB) of frequency estimation root mean square error. figure 1 Shown is the RMSE value of the improved algorithm based on the Hanning window, where s a =s 2 -s 1 .

[0138] As shown in the figure, overall the...

example 2

[0140] In order to verify the applicability of the improved algorithm, image 3 Shown is the RMSE simulation result based on the improved algorithm of rectangular window. The parameters of the simulated signal are the same as those in Example 1.

[0141] From image 3 It can be seen that with s 1 and s a The correction accuracy is improved with the increase of , and generally the simulation results based on the rectangular window are better than those based on the Hanning window. But when the SNR is greater than 30, the correction effect is not ideal.

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Abstract

The present invention relates to a time-shift phase difference-based high-precision frequency parameter estimation method. The method includes the following steps that: signals are sampled, and three time sequences are constructed; windowing is performed on the three time sequences, and DFT (Discrete Fourier Transformation) is performed; two normalized frequency correction quantity sets are obtained through phase difference; and element distances in the sets are calculated, with a signal energy maximum value adopted as a selection condition, an optimal signal frequency estimation value is selected. With the method of the invention adopted, constrains of the shift coefficients of a conventional time-shift phase difference-based correction method can be eliminated; the noise interference is decreased; the performance of the method can reach the Cramer-Rao lower bound (CRLB) under a certain noise environment; and the method has high anti-noise performance.

Description

technical field [0001] The invention belongs to the field of signal processing, and relates to a frequency correction method for signals, in particular to an improved time-shift phase difference spectrum correction method. Background technique [0002] In discrete spectrum analysis, due to the difficulty of truncating the signal throughout the period and the limited observation time, spectrum leakage and fence effects are inevitably introduced, which often leads to certain errors in the frequency, amplitude and phase of the spectrum components. Windowing technology can alleviate this defect to a certain extent, but it cannot completely solve it. For example, the maximum error of the amplitude can reach 36.4% and 15.3% respectively when analyzing the single harmonic with rectangular window and Hanning window. For any type of window function, the maximum frequency error is half of its frequency resolution. And the maximum phase error is even as high as ±90 degrees. Undoubte...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R23/16
CPCG01R23/16
Inventor 罗久飞苏祖强徐海涛萧红李锐郑凯
Owner CHONGQING UNIV OF POSTS & TELECOMM