SYSTEMS AND METHODS FOR DESIGNING A HIGH-PRECISION NARROWBAND DIGITAL FILTER FOR USE IN A COMMUNICATIONS SYSTEM WITH HIGH SPECTRAL EFFICIENCY

摘要

Systems and methods for transmitting information at very high data rates through narrowband communication channels are provided. The systems and methods involve modulating a message signal with a novel return-to-zero, abrupt phase modulation technique and filtering the modulated signal with a sophisticated high-precision digital filter. The digital filter is designed based on fractal modeling of the frequency spectrum of the modulated signal. The systems and methods of the present invention enable data rates exceeding 5 Mbps to be delivered through frequency channels as narrow as 50 KHz under a variety of channel conditions.