Direct-Sequence Spread Spectrum System
Abstract:
The purpose of this study is to construct and evaluate the performance of a direct-sequence spread spectrum DSSS system. The system, based upon a previously published design, uses a special type of injection- locked oscillator called a synchronous oscillator for code synchronization. The DSSS system was constructed in a manner that provides a test-bed for demonstrating spread spectrum principles and allows researchers to evaluate their own sub-system design concepts. The DSSS system, designed as a one-way link in the 420-450 MHz band, is constructed to operate in accordance with Federal Communications Commission rules and regulations pertaining to the Amateur Radio Service Part 97. Unlike conventional DSSS systems which combine digital data with a pseudorandom PN code sequence, the system described here directly modulates an FM modulated carrier with the PN code sequence.