Conventional direct-sequence and frequency-hopping spread spectrum systems utilize delay-lock loops to track the timing epoch of pseudonoise codes. These devices perform admirably at high signal-to-noise ratios (SNR), however, they are suboptimal at moderate and low SNR. A correlation loop that employs appropriately filtered pseudonoise signals for the local cross-correlation waveform may have superior performance under these conditions. The performance of this modified correlation loop will be determined by the cross correlation function of the transmitted waveform and locally generated reference signals, along with the statistics of the baseband equivalent noise process. In this work, we find the statistics of the baseband equivalent noise process. The approach is reasonably general and can be applied to a variety of signal structures and pre-correlation filters. In many interesting cases, it is possible to use Central Limit Theorem arguments to show that the equivalent noise is approximately additive, white and Gaussian over the loop bandwidth.

Meeting Name

1991 IEEE Military Communications Conference, MILCOM '91 (1991: Nov. 4-7, McLean, VA)


Electrical and Computer Engineering


Engineering Foundation


This work was supported in part by Engineering Foundation Grant #RI-B-90-25.

Keywords and Phrases

DLL; PLL; Baseband Equivalent Noise; Central Limit Theorem; Correlation Methods; Filtered Pseudonoise Signals; Filtering and Prediction Theory; First-Order Correlation Loop; Loop Bandwidth; Noise; Phase-Locked Loops; Precorrelation Filters; Thermal Noise

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 1991 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Nov 1991