The use of digital signal processing (DSP) techniques has significantly improved communication performance, but the troublesome problem of how to couple analog-modulated signals from a powerline modem to and from electrical wiring has not seen any significant developments. The analog signal processing circuitry, together with other components required to couple the modulated signal on and off the power line, is commonly given the collective name of analog front-end (AFE).


The AFE is called upon to provide voltage and current signal amplification, as well as providing galvanic isolation to protect the user and equipment being interfaced from both the nominal 120/240 volts and the transient voltages, which are common to power wiring. It is traditionally a complex circuit combining many discrete components with bulky isolation transformers.


This paper introduces a new approach to the AFE, which uses optical coupling technology to provide significant improvements in the areas of power efficiency, system robustness and overall solution cost.