| 摘要 |
A direct sequence spread spectrum (DSSS) DSP implementation technique utilizing a unique combination of multiple filters, transforms, despreading algorithm and spectral compression, all in a single coefficient set, providing a highly efficient system requiring relatively nominal computational hardware and software requirements. Reallocatable computational resources allow for frequency uncertainty in the transmitter, without the typical excessive noise bandwidth penalties. The present system further contemplates a unique energy detection algorithm for discerning spread spectrum while in the search mode, utilizing several discrete sampling data sets to increase signal strength, reducing noise, while changing the relative phase of the received chipping code with respect to the received signal. The spectral compression of the spreading sequence is achieved by representing the PRC as an array of two, complimenting fractional coefficients. The PRC code is filtered to achieve the required spectral compression characteristics, resulting in minimal despreading loss, while providing interference rejection of CW signals greater than 1.5 MHz from the center IF frequency.
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