New FSK / PSK complex modulation signal
|School||University of Electronic Science and Technology|
|Course||Communication and Information System|
|Keywords||Frequency Shift Keying ( FSK ) Phase shift keying PSK Complex modulation Pseudo-random|
In this thesis, with the state '95' military pre-research project 'low probability of intercept radar waveform' start and expansion. Given a new composite modulated radar signal waveform design method based on analysis of the frequency shift keying (FSK) and phase shift keying (PSK) modulation. The purpose of the design is the optimal allocation of finite energy emitted by the radar to the target feature information the design spectrum bandwidth of the signal contains frequency point. The method is also the frequency and phase of the digital modulation (FSK, PSK), design pseudo random FSK / PSK signal. Frequency coding is unevenly distributed, the probability density function of the extracted by radar observation target spectral information to determine the distribution of the frequency-encoding sequence, and reflected to the target; phase-encoded binary pseudo-random sequence, to take a uniform two-phase encoding, with abatement frequency pulse to bring the excessive correlation function sidelobes. Compared to other complex modulation signal, a distinctive feature of the pseudo-random FSK / PSK signal randomness and spectral adaptability. Each transmitter signal cycle design to meet certain statistical regularities, exactly the same statistical properties of the frequency domain, time-domain waveform is completely different, the signal itself is random; Second, hopping sequence (FSK) has the ability to reflect any distribution, so that the signal spectrum adaptability. Thesis of this signal theoretical analysis, discussion as to the application of the basic characteristics of the radar signal (spectral characteristics, ambiguity function from the resolution, speed, resolution, Doppler tolerance); research to meet certain statistical regularities the relevant characteristics of the signal; discussed the principle of radar target impulse response modeling, provide a theoretical basis for this modulation spectrum coding distribution of information extraction, illustration from the target echo of the the ideal scattering centers modeling target signal information extraction; gives a pseudo-random FSK / PSK signal received two applications; Finally, the use of Matlab autocorrelation receiver in the ideal case of no noise and cross-correlation received computational analysis. Can be drawn from the study, the signal of this design has a large BT, high-resolution features, low intercepted characteristics, resistance to electronic interference characteristics of randomness. Target detection, the ability to match any spectrum signal, representing the general radar signal stronger detection capability; due to the distribution of the design waveform frequency hopping sequence reflects the target distance information and waveform resolution characteristics as the target identification and imaging also has important significance.