Coded Phase Modulation Research Articles

Identification of dispersive communication channels using Barker codes

The identification of dispersive sommunication channels using short duration binary signals in considered in this paper. It is shown that Barker codes are the best known finite length binary test signals for the identification of the impulse response of base-bond channels using the cross-correlation technique. The identification of RF passband channels is performed by using RF pulse with Barker code phase modulation as test signals. The described identification method is suitable for adaptive digital communication systems operating in time varying channels. It is also suitable for channels that may show non-linear effects when long duration test signals are used for identification.

Multiple Pulse and Phase Code Modulation in the Loran-C System

Transmission of a group of closely spaced pulses increases the duty cycle and consequently the range of the Loran-C (formerly called Cytac) 100-kc pulsed hyperbolic radio navigation system while retaining the advantages of time sharing. Phase coding by carrier phase reversal, coupled with synchronous detection, facilitates automatic master and slave identification and search, and prevents multihop skywave interference. Instrumentation for simple and complex pulse patterns is considered. The phase codes used are characterized by lack of spurious responses associated with other bipolar codes.