The Ambiguity Function of Random Binary-Phase-Coded Waveforms
Abstract
The cross-correlation technique for signal detection and parameter estimation is widely used in communication and radar systems. For popular binary waveforms, the properties of their ambiguity functions have been studied for years. However, the results are generally restricted to specific codes which are either deterministic or pseudorandom. From the uncooperative reception viewpoint, without a priori knowledge of the emitted signal in many cases, the cross-correlating signals may be considered truly random. The report investigates the ambiguity function of truly random binary-phase-coded waveforms as an approximation to those waveforms commonly employed in binary-modulated pseudorandom systems/encoded radar systems. Here, in a statistical sense, the ambiguity function of a truly random binary-phase-coded waveform is analytically derived in which the normally used deterministic cross-correlation process is replaced by its ensemble average. Various doppler responses are presented and discussed. The results are compared with those obtained by transmitting an aperiodic maximum-length pseudorandom sequence. It is shown that the ambiguity function of the latter case is closely represented by the ensemble-average response of the truly random binary signal of equal length. With the transmitted signal unknown to a cross-correlator, the characteristics of the ambiguity function derived here provides predictive characteristics useful for practical cross-correlator system design.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 04, 1984
- Accession Number
- ADA148906
Entities
People
- Ching-tai Lin
Organizations
- United States Naval Research Laboratory