Common Bandwidth Tranmission of Information Signals and Pseudonoise Synchronization Waveforms

This paper describes methods for the simultaneous transmission of information signals and pseudonoise synchronization waveforms in a common bandwidth. For a relatively low level of the pseudonoise signal, a satisfactorily high synchronization accuracy is obtained by means of correlation techniques. Conversely, the information signal is detected with negligible interference due to the synchronization waveform. This permits a new approach to synchronization in speech systems and data transmission. The application to speech systems is quite straightforward. Emphasis is placed on design considerations for narrow-band systems with regard to output signal-to-noise ratio and acquisition performance. In data transmission the method is applied for bit and word synchronization. Thus, no restrictions are imposed on the transmitted data patterns and no inclusion of special synchronization words is required. In addition, the bandwidth of the system is not increased. The high accuracy required for synchronization in data systems is obtained here by a pseudoternary precoding of the transmitted data which is adapted to the spectral properties of the synchronization cross correlator. In this way the influence of the data signal on the received synchronization signal is minimized. Calculations of synchronization accuracy are given which include the effect of transmission noise.