BATTERY FEED CIRCUIT FOR SUBSCRIBER LINE

摘要

BATTERY FEED CIRCUIT FOR SUBSCRIBER LINE A battery feed circuit for a subscriber line including first and second feed circuit parts, each supplying a constant current to a corresponding subscriber line. The first and second feed circuit parts are provided with a common mode noise suppressor and/or a power source noise suppressor. The common mode noise suppressor includes first and second reference voltage output circuits and an intermediate voltage output circuit to produce the voltage between the first and second subscriber lines and superpose the same onto the thus output first and second reference voltages. The power source noise suppressor functions to cancel the outputs, concerning the power source noise voltage, at each output of the first and second feed circuit parts with each other.