Abstract: In a method of temperature stabilization of a reference voltage, in a first prespecified time interval, a current having a first constant amperage and, in a second prespecified time interval, a current having a second constant amperage and alternately applied to a pn junction. During the first and second time intervals, voltages at the pn junction are supplied to an input of an analysis circuit. The analysis circuit forms the difference between the two voltages and adds the difference in a weighted manner to a voltage obtained from one of the first and second amperages. The weighted result is applied to an output of the analysis circuit. The first constant amperage is applied to the pn junction during both the first and second prespecified time intervals and the second constant amperage is applied to the pn junction during the second prespecified time interval.

Abstract: In an information transmission system, in particular a telephone system, the subscribers can be connected to a dial exchange over a line. At the dial exchange end and at the subscriber end of the line are connected bidirectional multiplexers or demultiplexers over a bidirectional modem circuit which modulates and demodulates the data according to the intended transmission. If required, bidirectional compressor and decompressor circuit are connected to the multiplexers and demultiplexers, to which the subscribers are connected through a forward and a backward channel and a SLAC (bidirectional analog-digital converter (CODEC) with subscriber interface circuits (SLIC)), or to which a relaying device of the dial exchange is connected through drive circuits.

Abstract: A circuitry is disclosed for superimposing small, low energy (2) and large substantially higher energy (3) signals, in particular for transmitting speech signals with a remote supply direct signal for a receiving circuit or with a high energy alternating signal, for example a call alternating voltage for signaling. The circuitry includes an operational amplifier (1), having one input connected to a pole of a source supplying the small signal and operational voltage inputs being connected to a voltage supply source. In order to allow low energy, weak signals, such as speech signals, and high energy signals and direct voltages to be transmitted by such a circuitry over a subscriber line by means of simple components, the second pole of the small signal source (2) is connected to the second input of the operational amplifier (1) and one pole of a higher energy signal supply source (3) is connected to one pole of the voltage supply source (V).