Efficient Cyclic Spectrum Estimation Algorithm And Its Application

Direct Sequence Spread Spectrum (DS-SS) system modulates a data sequence to a high speed Pseudorandom (PN) sequence, which extends the bandwidth of the modulated signal while decreasing the Power Spectrum Density. It is an advanced communication system with many excellent properties such as Multiple Access, Low Probability of Interception, Anti-Jamming and so widely used. Because the DS-SS signals have cyclic features, the cyclostationary theory has been applied in the detection and parameter estimation of the signals, which is accomplished by exploitation of cyclic feature of signal through cyclic spectral analyzers. In the dissertation, two kinds of computationally efficient algorithms (including SSCA and FAM) for cyclic spectral analysises have been discussed detailly and deeply after introduce of the theory of spectral correlation, in addition, digital implementations of the corresponding algoritms architecture and the comparision of computational complexity are presented. The algorithm is implemented and simulated using matlab and DSP EVM board. In order to supply the actual BPSK DS-SS signal to verify the algorithms, this dissertation present a design method of spread spectrum signal generator with adjustable muti-parameter in detail. The contents of the dissertation are summarized as follows:1. After introduction of the spectral correlation, the time-smoothing and frequency-smoothing methods are discussed deeply. Chip width and carrier frequency estimation algorithms of DS-SS are presented as well.2. Two kinds of computationally efficient algorithms (SSCA and FAM) for cyclic spectral analysises have been discussed detailly and deeply, both of which are time-smoothing algorithms based on FFT. The theory of algorithms, digital implementations of algoritms architecture and the computational complexity are discussed detailly and deeply each. The performance of three kinds of algorithms FSM, FAM and SSCA is compared each other with the result of the matlab simulation.3. The methods to improve and enhance the performance parameters of frequency synthesizer, such as phase noise and frequency stability, are discussed detailly and deeply through the linear phase model of PLL which is using to implement the...