AC telephone signals bridge circuit - has transformer with four windings each with DC suppression filter and amplifier

摘要

The Hayes bridge, for AC telephone signals, connects two subscriber circuits and handles AC voice signals with superimposed DC. A transformer provides the coupling and each of its four windings is in parallel with one of four DC suppression circuits. Each DC suppression circuit consists of a filter allowing the DC component to pass through and connected in series with an amplifier. The ends of each winding are connected one to the filter input and one to the amplifier output.