Abstract: The present disclosure generally pertains to surge protection systems that protect outside plant equipment from high-energy surges. In one exemplary embodiment, a protection system is used for protecting Ethernet equipment that is coupled to an outside Ethernet cable. The protection system provides protection and remains capable of coupling signal energy between an Ethernet cable and Ethernet equipment without significantly degrading Ethernet performance. However, the protection system, while allowing the desirable Ethernet signals to pass between the cable and the equipment, prevents the electrical voltages and currents of high-energy surges, such as surges from lightning or AC power faults, from damaging the Ethernet equipment.

Abstract: A communication system adaptively cancels noise and/or interference from signals communicated through a communication channel, such as signals communicated by a telecommunication network. The system, based on a common mode signal of a received signal, generates an estimate of noise or interference within a differential mode signal of the received signal. The system then subtracts the estimate from the differential mode signal in an effort to remove noise from the differential mode signal thereby providing a differential mode signal that is substantially free of the estimated noise or interference.

Abstract: Protection circuits for protecting equipment connected to a telecommunication wire pair is disclosed. A protection circuit in one embodiment utilizes a series arrangement of solid state protectors wherein at least some of the solid state protectors are biased. The protection circuit reduces the level of intermodulation distortion in broadband signals that is caused by nonlinear capacitance of solid state protectors.

Abstract: A communication system adaptively cancels noise and/or interference from signals communicated through a communication channel, such as signals communicated by a telecommunication network. The system, based on a common mode signal of a received signal, generates an estimate of noise or interference within a differential mode signal of the received signal. The system then subtracts the estimate from the differential mode signal in an effort to remove noise from the differential mode signal thereby providing a differential mode signal that is substantially free of the estimated noise or interference.

Abstract: A communications connector includes an electrically non-conductive connector body having a terminal face. A plurality of connector terminals are positioned on the terminal face and arranged in a plurality of Tip/Ring terminal pairs, which are positioned substantially linearly with each other along the terminal face and arranged in alternating vertical and horizontal orientation of Tip/Ring terminal pairs and spaced to each other such that crosstalk among the Tip/Ring terminal pairs is cancelled.

Abstract: A sealing current system for a subscriber line that comprises a power source coupled to a first end of the subscriber line configured to apply a voltage to the subscriber line. The sealing current termination circuit coupled to a second end of the subscriber line configured to limit a current in the subscriber line, the current produced by the applied voltage.

Abstract: A protector block assembly interfaces a plurality of subscriber lines to communication equipment, such as digital subscriber line (DSL) modems. The assembly has a protector block into which surge protection modules are plugged. Each surge protection module limits the current that may pass from a respective subscriber line to communication equipment protected by the assembly. When plugged into the protector block, the surge protection modules are oriented such that crosstalk interference from the protector block is canceled thereby reducing the amount of crosstalk introduced by the protector block.

Abstract: The present disclosure generally pertains to surge protection systems that protect outside plant equipment from high-energy surges. In one exemplary embodiment, a protection system is used for protecting Ethernet equipment that is coupled to an outside Ethernet cable. The protection system provides protection and remains capable of coupling signal energy between an Ethernet cable and Ethernet equipment without significantly degrading Ethernet performance. However, the protection system, while allowing the desirable Ethernet signals to pass between the cable and the equipment, prevents the electrical voltages and currents of high-energy surges, such as surges from lightning or AC power faults, from damaging the Ethernet equipment.

Abstract: A system for canceling impulse noise comprises an adaptive impulse canceler and a combiner. The adaptive impulse canceler is configured to receive a common mode component of a received signal and to detect a noise impulse in the common mode component. The impulse canceler is further configured to provide, based on the noise impulse in the common mode component, an impulse noise estimation for a differential mode component of the received signal. The combiner is configured to receive the differential mode component and the impulse noise estimation and to subtract the impulse noise estimation from the differential mode component.

Abstract: A cable simulator that comprises an input device configured to receive a communication signal. The cable simulator further comprises a circuit configured to simulate attenuation in both the differential mode and common mode components of a communication signal.

Abstract: Typical amplifier circuits used to implement various type of power amplifiers, including line drivers, are capable of supplying high output currents while maintaining a low standby current. Variation in the manufacturing process, however, can lead to large variations in quiescent current of the amplifier. In particular, transistor mismatch and input offset voltage can cause the quiescent current to be very inconsistent from chip to chip. An amplifier in accordance with the present disclosure uses a transconductance amplifier to stabilize the quiescent current. The transconductance amplifier reduces the gain of the amplifier's input stage for very small signals such as the input offset voltage. The transconductance amplifier saturates for input signals larger than the expected offset voltage, allowing the normal high gain of the input stage to amplify the signal without significant gain reduction.

Abstract: A synthetic impedance telecommunication line driver has no electrical energy-dissipating elements in series with its output, and synthesizes its output impedance in accordance with current fed back from an output current (mirror) sensing circuit. This allows the driver to realize substantially reduced power requirements for driving a telecommunication line, such as, but not limited to a DSX-1 line. The driver includes an operational amplifier having a first polarity input coupled through an input resistor to an input port, to which a signal voltage to applied to an output port is coupled. A second polarity input of the amplifier is coupled to a reference voltage. A feedback resistor is coupled between the amplifier output and its inverting input. An output current-dependent current source, such as a current mirror coupled in circuit with the output node, generates a current as a small fraction k of the output current.

Abstract: A system has a first digital-to-analog (D/A) converter to receive a digital signal and to convert the digital signal into an analog pulse, a second D/A converter to cancel residual energy resulting from a previous pulse if a predetermined sequence of digital data is received, and a third D/A converter to control a falling edge of the analog pulse. Additionally, the system has logic to detect the sequence of digital data and to generate control data for at least one of the D/A converters from the digital data sequence thereby ensuring that the analog signal complies with the specified pulse mask template.

Abstract: To locate an open fault along a telecommunication wireline pair, a prescribed frequency tone is coupled to the wireline pair by way of a center tap of the transformer through which a line card is coupled to a subscriber loop. The line card's analog front end conducts capacitance to ground measurements on the tip and ring segments of the wireline pair. From these measurements, sum and difference distance values of respective tip and ring conductor lengths are derived. The sum and difference distance values are then processed to calculate the distance to the fault.

Abstract: The invention provides a switched linear amplifier for amplifying an input signal for provision to a communication medium. The switched linear amplifier includes a linear amplifier, an output current detector, and a switched inductive circuit. The linear amplifier amplifies the input signal to produce a linearly amplified signal. The output current detector is operative to detect an output current level having a magnitude greater than a predetermined threshold and provide a control signal. The switched inductive circuit is responsive to the control signal from the output current detector to provide an output current via a switched (and ideally lossless) inductive path, to provide a highly efficient means of generating a linearly amplified signal for provision to the communication medium.

Abstract: A method and apparatus for reducing signal distortion in a high speed data communications system caused by a flux imbalance in a system coupling transformer. The signal distortion is monitored by a combination echo canceller circuit connected to the equipment side winding of the transformer, thereby generating an error signal. Changes in the error signal are used by a flux controller to provide a flux cancellation signal. The flux cancellation signal is added with the data signal to generate an offsetting flux signal to the transformer.

Abstract: The invention provides a switched linear amplifier for amplifying an input signal for provision to a communication medium. The switched linear amplifier includes a linear amplifier, an output current detector, and a switched inductive circuit. The linear amplifier amplifies the input signal to produce a linearly amplified signal. The output current detector is operative to detect an output current level having a magnitude greater than a predetermined threshold and provide a control signal. The switched inductive circuit is responsive to the control signal from the output current detector to provide an output current via a switched (and ideally lossless) inductive path, to provide a highly efficient means of generating a linearly amplified signal for provision to the communication medium.

Abstract: A cable balance network for use in a full-duplex telecommunication system and method for optimizing the transhybrid loss of a full-duplex to half-duplex conversion circuit, said cable balance network comprising: (a) a plurality n of resistors Rn, each of said resistors Rn having a fixed resistance value dependent upon the impedance seen by the full-duplex port, and each of said resistors Rn, having a positive node and a negative node; (b) a plurality n−1 of capacitors Cn−1, each of said capacitors Cn−1 having a fixed capacitance value dependent upon the impedance seen by said full-duplex port, and each of said capacitors Cn−1 having a positive node and a negative node; and (c) a circuit configuration comprising at least two of said resistors R1, and R2 (n≧2) and at least one of said capacitors C1, such that all the negative nodes of each of said resistors Rn are effectively connected together, and such that the capacitor Cn−1is connected between the positive nodes of resistors

Abstract: A method and apparatus for providing an improved telephone hybrid function is provided. The present invention uses a transformer having an galvanically isolated sense winding to improve hybrid performance. Performance improvements include removing the effects of variations in winding resistance, independently adjusting a pick-off voltage, reducing the effects of transformer leakage inductance, providing DC isolation between circuits and increasing the signal to noise ratio at the receiver.

Abstract: The present invention provides a slope equalizer for use in a voice frequency channel card, which is preferably electronically and remotely controllable, and retrocompatible with existing telecommunication systems. The slope equalizer of the invention includes a high-pass filter followed by a variable gain stage amplifier, where the variable gain stage amplifier is an operational amplifier with a plurality of parallel input signal paths, each of the signal paths being a series-connected resistor and switch. The switch is preferably a FET transistor that is electronically and, optionally, remotely controllable. The circuit topology allows the use of FET transistors having relatively high on-resistances. A further advantage of the topology is that the FET switches are connected to a virtual ground by way of an operational amplifier, thereby reducing on-resistance modulation caused by signal variations across the FET.