Abstract: A transformerless hybrid circuit arrangement for a subscriber line interface circuit of a telecommunications exchange is disclosed. A preferred embodiment of the hybrid arrangement comprises a first and a second operational amplifier plus a differential amplifier connected together in the following manner: The non-inverting input of the first operational amplifier is connected to a first reference voltage and the output of this amplifier is connected (1) via a first resistor to one wire of the two-wire subscriber line, and (2) via a third resistor to the inverting input of the amplifier. The non-inverting input of the second operational amplifier is connected to a second reference voltage and to the receiving branch of the four-wire line of the telecommunications exchange.

Abstract: A transformerless hybrid circuit arrangement for a subscriber line interface circuit of a telecommunications exchange is disclosed. A preferred embodiment of the hybrid arrangement comprises a first and a second operational amplifier plus a differential amplifier connected together in the following manner: The non-inverting input of the first operational amplifier is connected to a first reference voltage and the output of this amplifier is connected (1) via a first resistor to one wire of the two-wire subscriber line, and (2) via a third resistor to the inverting input of the amplifier. The non-inverting input of the second operational amplifier is connected to a second reference voltage and to the receiving branch of the four-wire line of the telecommunications exchange.

Abstract: A transformerless hybrid circuit arrangement for a subscriber line interface circuit of a telecommunications exchange is disclosed. A preferred embodiment of the hybrid arrangement comprises a first and a second operational amplifier plus a differential amplifier connected together in the following manner: The non-inverting input of the first operational amplifier is connected to a first reference voltage and the output of this amplifier is connected (1) via a first resistor to one wire of the two-wire subscriber line, and (2) via a third resistor to the inverting input of the amplifier. The non-inverting input of the second operational amplifier is connected to a second reference voltage and to the receiving branch of the four-wire line of the telecommunications exchange.

Abstract: A plug-in module for an electronic device includes a header having conductors therein which extend therefrom to form terminals, and a substrate connected to the header and supporting electronic components connected to the conductors. One component has a projecting part which extends through the header and forms a guide to align the module with a socket, to facilitate plug-in of the terminals of the header. The module may be a channel element to control the frequency of a radio device and may include a resonant element, such as a piezo-electric crystal, and a coil for tuning a resonant circuit. The form for the coil may be the projecting part for aligning the module, and also provide access to a core therein for tuning the circuit when the module is plugged into the chassis. The module may include a conducting housing which cooperates with the header to form an enclosed structure. A grounding pin may be provided to establish a ground connection for the circuit on the substrate and for the housing.

Abstract: A colpitts oscillator having a tank circuit and a common base connected transistor, operating in a linear range, with an emitter-base junction coupled in the tank circuit and a load in the collector circuit thereof for passing current through the load at the frequency of the tank circuit.