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Nonlinear transformation-based phase-modulated signal frequency offset estimation and tracking method

A technology of nonlinear transformation and frequency offset estimation, applied in carrier adjustment, modulated carrier system, digital transmission system, etc., can solve the problems of low signal-to-noise ratio and poor capture accuracy in FFT spectrum analysis, and achieve improved signal-to-noise ratio, frequency Partial estimation and tracking with high precision and clear spectral lines

Active Publication Date: 2018-02-09
XIAN INSTITUE OF SPACE RADIO TECH
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Problems solved by technology

The higher sampling frequency determines that the signal-to-noise ratio of FFT spectrum analysis is low and the capture accuracy is poor

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  • Nonlinear transformation-based phase-modulated signal frequency offset estimation and tracking method
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  • Nonlinear transformation-based phase-modulated signal frequency offset estimation and tracking method

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Embodiment Construction

[0033] Specific embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0034] The principle block diagram of the present invention is as figure 1 As shown, the frequency offset estimation method is composed of modules such as digital down-conversion, low-pass filter, nonlinear transformation, FFT spectrum analysis, NCO compensation and closed-loop, and carrier discrimination. Where A is the amplitude of the input signal, I and Q are the modulated baseband data of the input signal, A0 is the amplitude of two quadrature signals generated locally, ω i and ω 0 are the angular frequencies of the input signal and the local carrier, respectively.

[0035] A method for estimating the frequency offset of phase modulation signals based on nonlinear transformation proposed by the present invention, the calculation process is as follows figure 2 As shown, the implementation steps are as follows:

[0036] (1) Acc...

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Abstract

The present invention relates to a nonlinear transformation-based phase-modulated signal frequency offset estimation and tracking method. According to the method, on the basis of theoretical analysison two-phase BPSK, four-phase balanced QPSK and unbalanced four-phase UQPSK modulated signals, primary nonlinear transformation or secondary nonlinear transformation is utilized to obtain symbol influence-removed radio frequency single-carrier signals, and therefore, preconditions are created for FFT (fast Fourier transform) spectrum analysis to realize carrier frequency offset estimation fast andaccurately. Compared with existing satellite technology which directly performs processing such as FFT spectrum analysis on phase-modulated signals, the method of the invention can assist solving technical shortcomings of dispersion of envelop spectrum peak points and large frequency offset estimation error and greatly improving the accuracy and real-time performance of frequency offset estimation and tracking of the phase-modulated signals, and has a bright application prospect in realizing carrier frequency offset estimation and tracking of phase-modulated signals of different links of a satellite.

Description

technical field [0001] The invention belongs to the technical field of satellite measurement and control and communication, and relates to a carrier frequency offset estimation and tracking method based on nonlinear transformation for phase modulation signals. Background technique [0002] In the process of satellite measurement and control and communication, phase modulation signals are generally divided into two-phase BPSK modulation, power balanced four-phase QPSK modulation, power unbalanced four-phase UQPSK modulation and so on. [0003] For two-phase BPSK and balanced four-phase QPSK, most of them adopt direct FFT spectrum analysis method at present to realize the acquisition process of radio frequency carrier. Due to the "parabolic" characteristic of the envelope spectrum after carrier phase modulation, the peak points of the envelope spectrum are dispersed (the top of the spectrum is relatively flat), making it difficult to accurately estimate the carrier frequency o...

Claims

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Application Information

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IPC IPC(8): H04L27/227H04L27/00
CPCH04L27/0014H04L27/2273H04L2027/0026
Inventor 赵鸿李静澜余晓川孙重磊
Owner XIAN INSTITUE OF SPACE RADIO TECH
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