Measured noise performance of a direct-sequence spread-spectrum system and a comparison of single-vice dual-channel delay-lock loops

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Authors
Bartone, Chris G.
Subjects
Direct-Sequence Spread-Spectrum
BPSK
LPI
Communications
Delay- Lock Loop
Processing Gain Spread Spectrum
AJ
AM
AM-DSB-SC
Advisors
Myers, Glen
Date of Issue
1987-09
Date
Publisher
Language
en_US
Abstract
A direct-sequence (DS) spread spectrum system which could be used by a conventional amplitude modulated (AM) radio system was designed, built and tested. A delay-lock loop was used to provide code synchronization in the receiver. The noise performance of a single-channel delay-lock loop (SCDLL) was compared with a dual-channel delay-lock loop (DCDLL) with no data being transmitted. When data was transmitted a DCDLL was used and the noise performance (probability of bit error) of the DS spread spectrum system was measured. Test results indicate that the SCDLL performs as well as or better than the DCDLL. The measured noise performance of the DS spread spectrum system was within 5 dB of theoretical values for a spreading factor of 255. Conclusions are that apart from hardware simplicity, the SCDLL provides, in practice, a noise performance advantage relative to the DCDLL and that this DS spread spectrum system can be used to transmit low rate digital data reliably at values of SNR much less than unity. It is recommended that this DS spread spectrum system be considered by the Department of Defense to be implemented in AM radio systems to provide low data rate anti-jam/interference rejection capability.
Type
Thesis
Description
Series/Report No
Department
Electrical Engineering
Organization
Naval Postgraduate School
Identifiers
NPS Report Number
Sponsors
Funder
Format
103 p.
Citation
Distribution Statement
Approved for public release; distribution is unlimited.
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