High-speed carrierless passband transmission over the local cable network

The carrierless (linear and nonlinear) equalization theory of two-dimensional digital signals perturbed by wire pair intersymbol interference (ISI) and Gaussian-distributed near-end crosstalk (NEXT) or foreign thermal noise is developed, leading to the interpretation of the carrierless AM/PM double sideband modulation technique. The potential NEXT- and thermal-noise-limited throughput capabilities of uncoded linearly and nonlinearly feedback-equalized carrierless AM/PM digital signals observed through twisted metallic pairs bundled in a multicore transmission cable are examined. For each modulation technique and receiver structure, theoretical comparisons are derived on the basis of an information-rate versus baud rate optimization procedure. Curves and tables for a variety loop attenuation frequency characteristics indicate that a trellis-coded (Tomlinson precoded) carrierless passband decision feedback equalizer is capable of accommodating all projected versions of the high-bit-rate digital subscriber line (HDSL) data transmission system