Comparison of Synchronization Techniques for the AFIT Direct Sequence Spread Spectrum System.

摘要

The purpose of this study is to analyze and evaluate the performance of several code synchronization methods that could be used in the Air Force Institute of Technology's (AFIT) Direct-Sequence Spread Spectrum (DSSS) communication system. These methods include the sliding correlator, transmitted reference, sequential estimation, and three types of matched filters. The matched filters are the baseband matched filter, delay line matched filter, and the convolver. The criteria used for the evaluation of these synchronization methods are theoretical synchronization times and probability of bit-error. Advantages and disadvantages of each synchronization method are described and a method is recommended to be tested in the existing AFIT DSS system prototype. The effect of adding a PLL circuit to the AFIT system needs to be investigated, especially the effect on the bit-error curve measured by James Stephens when he built the AFIT system. A matched filter convolver should be added in place of the synchronous oscillator. Synchronization, Direct-sequence Spread Spectrum.