Abstract: A circuit arrangement for a line test and for feeding a corrosion protection current into a two-wire line comprises a controllable ramp generator for producing a ramp voltage, at least one first test impedance to be connected to a first line of a two-wire line, at least one second test impedance to be connected to a second line of the two-wire line, at least one first and second controllable switches for connecting the ramp voltage to the first and second test impedances, and a programmable control device for controlling the ramp generator and the first and second controllable switches in such a way so that the ramp voltage is coupled to the two-wire line in order to produce a corrosion protection current. The control device switches at least one of the first and second test impedances to the respective of the first and second lines for a line test.

Abstract: A circuit arrangement for bidirectional current limiting comprises a first transistor, a second transistor, a first resistor, a first zener diode and a second zener diode. The first transistor comprises a first controllable path and a first control terminal and the second transistor comprises a second controllable path and a second control terminal. The first and the second control terminals are connected to a first current source and the first resistor is connected between the first and the second controllable paths. The first zener diode is connected between the first current source and a first line node which is located between the first controllable path of the first transistor and the first resistor. The second zener diode is connected between the first current source and a second line node which is located between the second controllable path of the second transistor and the first resistor.

Abstract: A current-saving differential wideband driver circuit comprises a differential input amplifier for amplifying a differential input signal to produce a differential intermediate signal being comprised of a first intermediate signal and a second intermediate signal, a first transimpedance amplifier comprising a first inverting input, a first non-inverting input, and a first output, and a second transimpedance amplifier comprising a second inverting input, a second non-inverting input, and a second output. The first intermediate signal is applied to the first non-inverting input, the first output is connected to the first inverting input of the first transimpedance amplifier via a first feedback resistor for negative current feedback, the second intermediate signal is applied to the second non-inverting input, and the second output is connected to the second inverting input of the second transimpedance amplifier via a second feedback resistor for negative current feedback.

Abstract: A circuit arrangement for a line test and for feeding a corrosion protection current into a two-wire line comprises a controllable ramp generator for producing a ramp voltage, at least one first test impedance to be connected to a first line of a two-wire line, at least one second test impedance to be connected to a second line of the two-wire line, at least one first and second controllable switches for connecting the ramp voltage to the first and second test impedances, and a programmable control device for controlling the ramp generator and the first and second controllable switches in such a way so that the ramp voltage is coupled to the two-wire line in order to produce a corrosion protection current. The control device switches at least one of the first and second test impedances to the respective of the first and second lines for a line test.

Abstract: The invention relates to a line driver arrangement for driving signals via at least one subscriber line, provided with: an input for injecting an input signal and having an output at which a signal which is to be driven via the subscriber line can be tapped off, a digital amplifier which produces a pulse-width-modulated signal on the output side from the input signal or from a signal derived from it, an analog amplifier, which produces an analog signal on the output side from the input signal or from a signal derived from it, with the outputs of the amplifiers being coupled such that the signal to be driven results from superimposition of the analog signal and the digital signal, with the gain of the analog amplifier being matched to the gain of the digital amplifier such that scatter and/or overshoot on the digital signal are at least reduced after the superimposition.

Abstract: A circuit arrangement for bidirectional current limiting comprises a first transistor, a second transistor, a first resistor, a first zener diode and a second zener diode. The first transistor comprises a first controllable path and a first control terminal and the second transistor comprises a second controllable path and a second control terminal. The first and the second control terminals are connected to a first current source and the first resistor is connected between the first and the second controllable paths. The first zener diode is connected between the first current source and a first line node which is located between the first controllable path of the first transistor and the first resistor. The second zener diode is connected between the first current source and a second line node which is located between the second controllable path of the second transistor and the first resistor.

Abstract: A supply circuit for supplying a two-wire line comprises a first resistor connected between a first supply voltage potential and a first two-wire line connection of a two-wire line, a current-limiting device connected between a second two-wire line connection of the two-wire line and a second supply voltage potential and providing the two-wire line with a limited current on the basis of a variable setting potential, and an impedance-matching device connected between the second two-wire line connection and the second supply voltage potential and providing the variable setting potential on the basis of a reference potential and a voltage across the current-limiting device. The first resistor has a first impedance and the impedance-matching device and the current-limiting device form a second impedance being present at the second two-wire connection. The first and second impedances are essentially the same.

Abstract: Driver circuit for driving a useful signal having: (a) at least one amplifier circuit (3a, 3b) with low output impedance for the signal amplification of the useful signal; (b) a protection impedance (9a, 9b) respectively connected downstream of the amplifier circuit (3a, 3b) and serving to protect the amplifier circuit (3a, 3b); characterized in that (c) provision is respectively made of a feedback circuit (14a, 14b) for the frequency-dependent signal feedback of the useful signal amplified by the amplifier circuit (3a, 3b).

Abstract: The invention provides a transmission apparatus for line signals (206a, 206b) having a line device (201) for transmitting the line signals (206a, 206b) at prescribed signal levels and having a line driver device (100) which has an amplifier unit (101) and a control unit (105). A determination unit (102) is used to change over the operating mode of the amplifier unit (101) when a signal level for the line signals (206a, 206b) exceeds a prescribed reference level (113a, 113b) by virtue of a determination unit (102) having established that a prescribed reference signal level (113a, 113b) has been exceeded by the signal level of the line signals (206a, 206b).

Abstract: Driver circuit for at least one subscriber terminal, comprising a first driver (14) for amplifying the power of a direct-voltage signal applied for supplying power to the subscriber terminal, the first driver (14) being supplied by a first supply voltage (V1), and comprising a second driver (37; 37a, 37b), following the first driver, for modulating high-frequency signal currents onto the power-amplified direct-voltage signal.

Abstract: Broadband driver for signals that are transmitted in different frequency ranges, comprising: (a) a first broadband driver circuit (19) for driving first signals having signal frequencies that lie in a first frequency range; (b) a second broadband driver circuit (24) for driving second signals having signal frequencies that lie in a second frequency range; (c) where at least one of the two broadband driver circuits (19) has a frequency-dependent positive-feedback circuit (44) for impedance synthesis of a frequency-dependent output impedance (Zout) of the broadband driver circuit (19), and where the output impedance (Zout) has a different value in the first frequency range than in the second frequency range.

Abstract: Driver circuit for driving a useful signal having: (a) at least one amplifier circuit (3a, 3b) with low output impedance for the signal amplification of the useful signal; (b) a protection impedance (9a, 9b) respectively connected downstream of the amplifier circuit (3a, 3b) and serving to protect the amplifier circuit (3a, 3b); characterized in that (c) provision is respectively made of a feedback circuit (14a, 14b) for the frequency-dependent signal feedback of the useful signal amplified by the amplifier circuit (3a, 3b).

Abstract: Transceiver for transmitting and receiving voice and data signals includes a voice signal driver configured to operate in idle or working operating modes, during which it has a high or low output impedances respectively. A data signal driver drives an analog data transmission signal via a channel to the subscriber. A data reception circuit that converts a received analog data reception signal into digital reception data includes a multiplication circuit for multiplying the digital reception data by compensation coefficients selected to compensate for channel distortions, an identification circuit connected to the channel for providing an identification signal indicative of whether the subscriber terminal is on or off-hook, and a control circuit to select the operating mode in response to the identification signal and to determine compensation coefficients to compensate for a change in the channel resulting from a change in the output impedance of the voice signal driver.

Abstract: The invention relates to a line driver arrangement for driving signals via at least one subscriber line, provided with:

Abstract: Tracking circuit for tracking the voltage potential of an insulation well for the insulation of an integrated component (1) embedded in the insulation well, the voltage potential of the insulation well being tracked in a manner dependent on a signal voltage output by the integrated transistor (1) in such a way that the voltage difference between the output signal voltage and the tracked voltage potential is lower than a predetermined breakdown voltage (UDA) between the integrated transistor (1) and the insulation well.

Abstract: Driver circuit for driving voice and data signals from a switching center via a subscriber line (38) to a subscriber terminal, having: a controllable voice signal driver (12) which has a high output impedance in a quiescent operating mode and, in a working operating mode, drives an analog voice signal from the switching center via the subscriber line (38) to the subscriber terminal, with a low output impedance; a controllable data signal driver, which has a high output impedance in the quiescent operating mode and, in the working operating mode, drives an analog-modulated data signal in a data transmission frequency band (&Dgr;f) from the switching center via the subscriber line (38) to the subscriber terminal; an identification circuit (27), which, in the quiescent operating mode, identifies a current rise in a current flowing via the subscriber line (38) when the subscriber terminal is picked up, and produces a pick-up identification signal; and having a CODEC circuit (4), which, on receiving the pick-u

Abstract: A transceiver for a transmission and reception signal which can be transmitted via a signal line having a particular line impedance (ZLINE), having a line driver (6) for driving a transmission signal via the signal line and having an analog echo cancellation filter (15) for signal suppression for an echo signal brought about by the transmission signal, where the line driver (6) has a synthesized output impedance (RSYN), with the line driver (6) having a downstream hybrid circuit (11) for connecting an analog echo cancellation filter (15).

Abstract: Tracking circuit for tracking the voltage potential of an insulation well for the insulation of an integrated component (1) embedded in the insulation well, the voltage potential of the insulation well being tracked in a manner dependent on a signal voltage output by the integrated transistor (1) in such a way that the voltage difference between the output signal voltage and the tracked voltage potential is lower than a predetermined breakdown voltage (UDA) between the integrated transistor (1) and the insulation well.

Abstract: Driver circuit for at least one subscriber terminal, comprising a first driver (14) for amplifying the power of a direct-voltage signal applied for supplying power to the subscriber terminal, the first driver (14) being supplied by a first supply voltage (V1), and comprising a second driver (37; 37a, 37b), following the first driver, for modulating high-frequency signal currents onto the power-amplified direct-voltage signal.

Abstract: Differential line driver circuit for driving a line signal output via a signal line.