GAFFELKRETSANORDNING FOR FORBINDNING AV EN DUBBELRIKTAD BANA MED EN INKOMMANDE OCH EN UTGAENDE BANA

摘要

This specification discloses a time division communication system having a plurality of line circuits for coupling telephones over bidirectional lines to outgoing and incoming time division buses. Each of the line circuits comprises an active hybrid having separate transmit and receive operational amplifiers for connecting the outgoing and incoming buses to a telephone line via interface circuitry and during selected time slots of a time division frame. The interface circuitry comprises transformer and capacitor arrangements for coupling a bidirectional telephone line via a filter to an input of the hybrid transmit amplifier and an output of the receive amplifier. The filter together with a phase lead compensation network, a negative feedback resistor and a resistor-capacitor bias arrangement cooperate to control hybrid balance, stability and frequency response.