Binary Orthogonal FM Technique with Multiple Properties

Theoretical and practical aspects of the design of a binary FM signal originating from a single frequency source are presented. Such a technique permits a high degree of frequency and phase stability which cannot be achieved with conventional methods. The line frequencies are inherently locked to the bit speed, are orthogonal to each other, and always have a predetermined phase at the bit transition points. Consequently, the intersymbol interference is negligible and the original message can be recovered by noncoherent FM or a coherent process using either differential or absolute reference. There is no need to maintain such an absolute reference at the receiver, since the reference forms an inherent part of the transmitted signal and is easily separable. Three simple and practical embodiments of the system are presented; either method generates the desired signal and reconstructs the original data input. Finally, the experimental model is discussed and certain empirical results presented.