Stmicroelectronics S.r.l.

Sgs-thomson Microelectronics S.r.l.

Sgs-thomson Microelectronics Limited

Carlo Antonini

Pietro Consiglio

Ferdinando Lari

Vanni Poletto

Salvatore Cannavacciuolo

Walter Rossi

Luigi Vergani

Gianpietro Vanalli

An analog-to-digital conversion loop adapted to generate a digital output signal corresponding to a low-pass filtered replica of an analog input signal, including an analog adder configured to receive the input analog signal and an analog feedback signal, adapted to generate an analog error signal corresponding to the difference between the analog input signal and the analog feedback signal; an analog-to-digital converter having a nonlinear input-output conversion characteristic defining a larger quantization step the more the input to be converted differs from a null value, configured to receive the analog error signal and to generate a corresponding digital error signal a digital integrator configured to receive the digital error signal, configured to generate the digital output signal corresponding to the time integration of the digital error signal; a digital-to-analog converter, configured to receive the digital output signal and to generate the analog feedback signal as analog replica of the digital output signal.

Analog-to-digital conversion loop for PS15 and WSS systems

A subscriber's telephone system is presented that includes at least one driver circuit connected to Tip and Ring terminals. An additional network is connected between an output of the driver circuit and the Ring terminal. This additional network includes a suitably dimensioned capacitor and a diode limiter connected in parallel with each other to minimize the overall voltage while maintaining a desired battery mean value.

Telephone subscriber system

MOS transistors substitute circuit having a transformer/data interface function, particularly for ISDN networks and corresponding control and driving switch configuration

An acoustic feedback suppression system, particularly for auxiliary ringers in socket telephone systems, comprising a first terminal and a second terminal of a telephone line, an internal ringer, and an auxiliary ringer that is connected between the first and second telephone lines. The system comprises an activation circuit adapted to activate first and second switching circuits to reduce the voltage at the terminals of the auxiliary ringer, the activation circuit being controlled by an activation signal generated by a control and signaling circuit when a user dials a telephone number.

System and method for supressing pulse dialing feedback occurring

A telephone interface circuit with impedance termination during call pauses, comprising first and second terminals to connect to a telephone line and a line termination branch connected to the first terminal across a decoupling capacitor, and to the second terminal. The line termination branch includes an intersection node, a first switch and a first impedance resistor between the first terminal and the intersection node, and a second switch and a second impedance resistor between the second terminal and the intersection node. The intersection node is connected to ground across a third switch. The first switch, the second switch, and the third switch are controlled by a control unit by first, second and third control lines, respectively. The telephone interface circuit further comprises a ring signal detector that is connected to a microprocessor unit capable of activating the control unit in an interval in which the circuit must be terminated for CLID (Calling Line IDentification) transmission.

Telephone interface circuit with impedance termination during call pauses

Distortion control in a push-pull output stage of a speech amplifier of a telephone powered through the telephone line is more effectively and advantageously implemented by independently sensing an eventual state of saturation reached by any of the two output transistors of the amplifier, summing the current signals representative of the sensed state of saturation of either or both output transistors, integrating the resulting sum current signal to produce a DC signal and using the DC signal for activating an AGC loop. The DC signal indiscriminately accounts for any cause of saturation, though virtually representing the level of the amplified AC signal. Distortion may be controlled without penalizing output voltage swing and power consumption.

Control of distortion in a line-powered amplifier with a rail-to-rail

A telephone subscriber system comprising a speech circuit and a ring circuit adapted to be integrated monolithically to a semiconductor material substrate and being coupled to a telephone subscriber line, respectively through first and second circuit switch of the diode bridge type, further comprises a first circuit changeover switch, under control by the user, which drives at least second and third circuit switching means connected between the first diode bridge circuit and the speech circuit. The third circuit changeover switch is connected to the speech and ring circuits at a circuit communication node which forms the system point of reference, physically coincident with the substrate. The system includes a circuit interface means for controlling the second and third circuit changeover switch by external electrical signals which are related to the circuit communication node. The circuit interface circuit comprises a diode connected with its cathode to the circuit communication node, in parallel with the third circuit changeover switch.

Telephone subscriber system incorporating a drive interface for a

An acoustic feedback suppression device, particularly for auxiliary ringers in plug-in telephone systems, includes diodes in addition to a rectifier bridge of the ringer. The circuit provides direct-current decoupling and limits the AC voltage present across the auxiliary ringer.

Growing community of inventors

Venegono Inferiore, Italy

Carlo Antonini