Siemens Aktiengesellschaft

Compagnie Industrielle Des Telecommunications Cit-alcatel

Alcatel N.v.

Alcatel Cit

Pierre Albouy

Robert Lechner

Hans-Werner Rudolf

Nigel P Dyer

Harald Stader

Norbert Wingerath

Virgilio Mosca

Robert K Galpin

Antonio Nicastro

Ramatchandirane Nadaradjane

Christopher C Priest

Robert Le Gougnec

Marcello Manca

Francois Botquin

Roberto Cordani

Gerard Chartie

Guy Cochennec

Yves Salahun

A wideband amplifier circuit having automatic offset voltage and gain control, the circuit comprising a main amplifier chain, a negative feedback loop for controlling gain, and a negative feedback loop for controlling and cancelling any possible offset voltage at its output, said main amplifier chain including a gain control amplifier block having a gain control input connected to the gain control negative feedback loop; wherein the gain control amplifier block is preceded in the main chain by a symmetrizer-adder block of fixed gain having a first input constituting the input of the amplifier circuit and a second input connected to the negative feedback loop for controlling and cancelling any possible offset voltage at the output.

Wideband amplifier circuit having automatic gain and offset voltage

A laser power supply and control device for a fiber optic link between a subscriber and a telecommunications central office provides selection of one of two data sources and varies the laser current. The device includes a current generator controlled by an activation signal and delivers a laser current to a laser that can be varied. A selector circuit is connected to the two data sources. An output modulator has an input connected to the current generator which delivers the laser current thereto and to the selector circuit which delivers the transmit data. Its output is connected to the laser to which it delivers the laser current modulated by the transmit data. In the absence of data to transmit the value of the activation signal, the current generator is disabled so that the laser is not energized.

Laser power supply and control device for a fiber optic link between a

A digital interface between at least two subscriber line interface circuits and a processing unit is described. The interface is configured in the form of a parallel interface. The level of an input/output register and of a control register is allocated, as needed, to the connections of the processing unit. These connections can be operated selectively as inputs or outputs. They can also be operated in two modes, depending upon which type of subscriber line interface circuit (SLIC) is connected. The connections of the last-mentioned units are partially operable as inputs or outputs and partially operable only as inputs but in the input case, selectively for various types of input signals.

Digital interface between at least two subscriber line interface

A digital interface of an integrated subscriber line interface circuit is provided. The interface serves for the connection of a signal processor unit. Individual connections are used as signal inputs in signal entry operation of the interface, and as signal outputs in signal transmission operation. Other connections are used as signal inputs in both operating mode, but receive different signals in each operating mode. One group of connections includes two registers with respective associated decoders to enable switching from one to the other, so that the number of operating instructions that can be represented by means of binary signal value combinations applied to the connections is doubled.

Digital interface of an integrated subscriber line interface circuit

The apparatus comprises a zero pass detector (2) for detecting zero passes in a voltage signal proportional to the line current to generate a pulse signal constituted by positive and negative rectangular pulses of equal amplitude and of width dependant on the duty ratio of the line signal, a pulse signal processor constituted by a saturable integrator circuit (4) connected to integrate the pulse signal and to deliver a triangular signal having a positive peak value which increases after ringing has been answered, a comparator (6) connected to compare the triangular signal with a positive reference voltage (+Vr) and to deliver a loop detected signal when the peak value reaches the reference value, the loop detected signal being applied to a bistable logic device (8) which serves to store the loop detected signal and to deliver an output signal from the apparatus based on the stored signal.

Apparatus for detecting a loop during ringing

An electronic subscriber junctor for connecting a subscriber line to a telephone exchange, comprising an output amplifier circuit connected to the line, first means for generating a compensation voltage proportional to a common mode voltage occurring on the line and for providing a direct current proportional to a DC component of the line current, second means for obtaining a constant current, for algebraically summing said constant current and said direct current, and for supplying to the output amplifier circuit a first control current equal to said algebraic sum of the constant current and the direct current, third means for providing from said compensation voltage, via two connecting wires and on each wire, a second control current to the output amplifier circuit so as to compensate for longitudinal currents on the line, each connecting wire carrying the first control current and the output amplifier circuit delivering on each line wire a current proportional to the algebraic sum, on each connecting wire, of the first and second control currents, and an interface circuit connected to the first means and to the telephone exchange.

Electronic subscriber junctor

Growing community of inventors

Lannion, France

Pierre Albouy