Study On Pseudo Random Pulse Position Modulation And Pseudo Random Coded Phase-modulation Compound Fuze

Focusing on Pseudorandom Pulse Position Modulation and Pseudorandom Coded Phase modulation Compound Fuze (PRPPM-PRBC), this dissertation mainly studies the characteristics of basic signal, the performance of counter-reconnaissance and antijamming, the excision methods of several typical interferences and system implemental circuits. As one part of the research fields of compound systems of pseudorandom code, the researches would be of great reference to the electronic reconnaissance and counter measures of related Pseudorandom Coded Phase modulation systems such as communication and radar.The dissertation falls into the following four parts:(1) This dissertation explores into the systemic structure and principle of the compound fuze, studies the principle and several performances of preconcerted distance, analyses engineering waveforms and finally deduces and simulates autocorrelating function, spectrum and Ambiguity function of PRPPM-PRBC compound fuze, the results of which show that the compound fuze keeps the superior autocorrelating character of Pseudorandom Code and at the same time, it possesses some random characters.(2) The counter-reconnaissance performance of the compound fuze are discussed in terms of Reconnaissance distance, reconnaissance intercept and capture probability. And the antijamming capabilities on noise and interferences of LFM, NAM, NFM and Pseudorandom Coded Phase-modulation are also analyzed.(3) The excision of several typical interferences including suppressing principles and processes based on modern time-frequency signal processing methods are also discussed. With the help of simulation analysis, the excision effects on each interference are proved. LFM excision based on FRFT, the NFM excision based on twice square transformation, the excision of Pseudorandom Coded Phase-modulation based on envelope filtering and twice square transformation are the details.(4) In the fifth chapter, this dissertation gives the principle implemental frame of the compound Fuze, brings forward the compound modulating scheme of Pseudorandom Coded Phase modulation first then Pseudorandom Pulse Position Modulation. And several other functional units are designed and tested including local oscillation circuits based on ADF4360, Pseudorandom Coded Phase-modulation unit based on ADF8349, PRPPM unit based on BAS70-04LT1, demodulating circuits based on ADF8347 and signal processing unit based on XC95144. Finally the function and several characters of digital correlation of PRPPM-PRBC compound fuze are analyzed by simulation.