On the Feasibility and Optimization of Linear Frequency Modulation on Digital Signalling

摘要

Research on the feasibility and optimization of linear frequency modulation (LFM) in binary digital signalling is carried out and reported. The analysis is achieved for a number of channel mechanisms for which a comparison of LFM and the more conventional techniques is made. For coherent reception of non-fading signals in additive interference, it is shown that optimal LFM excels over the more conventional FSK in terms of relative energy and error rate. However, anticoherent signal sets (PSK) are seen as the best for employment in this situation. The study proceeds with an examination of Rayleigh and Rician scatter mechanisms from which is obtained an interrelation of error rate, scatter field coherence, and pertinent signal design parameters, for optimal reception of a general binary signal set. Finally a study of the impairments incurred by conventional receivers in a discrete multipath environment producing fading and intersymbol interference is introduced and an analytical treatment of detection error probability employing discrimination between primary and secondary signals is demonstrated for LFM. An identical analysis is carried out for discrete FM. It is concluded that LFM is a vital consideration in the reception of discrete multipath producing fading and intersymbol interference for systems in which high data rates relative to the multipath structure must be maintained. (Author)