Transformer-less hybrid circuit

Abstract

An improved transformer-less electronic isolating transformer is obtained with an output subcircuit that outputs a controlled current rather than voltage. Specifically, the improved hybrid comprises an output drive subcircuit that receives an ac signal and creates a corresponding current that is passed to the line that supports two way communication. The subcircuit not only converts the applied voltage to current but includes means for effecting gain. Signals arriving to the hybrid from the line are applied directly to a near-end echo circuit that is also responsive to the signal applied to the output drive subcircuit. Both the input of the output drive subcircuit and the output of the near-end echo subcircuit are isolated with opto-isolators that employ photodiodes in their photo-voltaic mode.

Dependencies are inferred from the claim text.