Power-Level Adaptive Synchronization Circuit for Spread-Spectrum-BOK-Receivers in Burst Transmission Systems

Certain military communication systems are based on the jam-resistant burst transmission of binary telegrams which consist of orthogonal spread-spectrum waveforms (BOK). To regain the message content at the receiver the a priori not known arrival times of the telegrams have to be detected by means of a synchronization circuit. In this paper a novel power-level adaptive synchronization circuit for producing the telegram alarms is proposed. This circuit shows CFAR-performance in the case of noise jammers but does not show the degradation typical for other synchronization systems (e.g. systems employing a hard bandpass limiter at the receiver front end) if other types of jamming signals are received. The performance of the synchronization circuit is theoretically analyzed for noise jam mers and CW-sine jammers. Some considerations concerning the influence of pulsed jammers are also included. Measurements finally confirm the theoretical results.