Quadrature Phase Shift Keying Signal Spectrum Estimation Method

Abstract

The present invention provides a quaternary phase shift keying signal spectrum estimation method for estimating the spectral parameter of the phase modulation signal of the quaternary phase shift keying of a complex electromagnetic space based on the mode of fast Fourier transform spectral fitting. The method comprises a step of carrying out dephasing modulation processing on a quaternary phase shift keying signal, a step of carrying out spectral line fitting weakening barrier effect on the quaternary phase shift keying signal which is subjected to the dephasing modulation processing, a step of accurately estimating the spectrum combined with the mode of spectrum complex coefficient decoherence so as to obtain a spectrum estimation result, and a step of using a threshold sliding iterative mode to optimize the spectrum estimation result, and thus ensuring the obtainment of a most effective spectrum estimation result. Accordingly, by employing the present invention, the center frequency of the QPSK signal can be accurately estimated, in a low SNR condition, and a result shows that the spectral estimation accuracy still can reach about 0.5KHz even when a signal power level is low as -110dBm.

Description

technical field [0001] The invention belongs to the field of frequency spectrum analysis of complex electromagnetic environment signals in space, and relates to a method for estimating frequency spectrum of quadrature phase-shift keying signals, which is suitable for high, medium and low-orbit satellites, near-space vehicles and various aircrafts for four-phase analysis of complex electromagnetic space. Estimation of Spectral Parameters of Phase-Shift Keyed Phase-Modulated Signals. Background technique [0002] The radio communication spectrum covers the electromagnetic radiation frequency band from tens of MHz to tens of GHz. The spectrum provides services for military and civilian radio services in various fields. These all depend on the effective spectrum management of dedicated communication systems, and spectrum monitoring is the basis of spectrum management. means. Furthermore, for spacecraft, the space electromagnetic environment is complex and changeable, electromag...

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Problems solved by technology

[0005] In order to solve the problems existing in the prior art, the present invention proposes a new QPSK signal spectrum estimation algorithm based on FFT spectrum fitting, which can effectively solve the problem of QPSK signal under the condition of low signal-to-noise ratio in complex space electromagnetic environment. Precise Spectrum Estimation of Modulated Signals

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