Abstract: A multi-stage differential amplifier and method provides a gain versus frequency warping response characteristic that equalizes a transmission line of a given length to compensate for frequency-dependent attenuation. The warping response characteristic comprises the inverse of the attenuation versus frequency characteristic of the line, and affords a substantially flat system gain response over a predetermined frequency spectrum. The individual amplifier stages employ operational amplifiers, and are designed using SPICE simulations such that the individual responses of the stages are tailored so they combine to provide the required overall warping response to compensate the line.

Abstract: Apparatus and methods for deriving power from an active POTS twisted pair of lines for powering associated auxiliary electrical devices, such as signal processing electronics, includes a power supply for providing a regulated DC voltage and current, and a current regulator for limiting the current flowing in the twisted pair to a predetermined value that does not disrupt the normal signaling and operation of the telephone circuit. Another current regulator in the power supply limits the input current from the twisted pair during power surges to another predetermined value that prevents line latching in an off hook condition. A shared power arrangement derives power from a plurality of twisted pairs and powers another plurality of auxiliary electrical devices in parallel, thereby limiting the line current of any one twisted pair to a value that avoids disrupting the normal operation of the telephone circuit.

Abstract: An analog electronic circuit is placed between the central office of a telecommunications provider and the customer premises equipment of a digital subscriber line system which uses unshielded twisted pair wires (“UTP”). The electronic circuit separates the downlink signals from the uplink signals with a first mixer. The voice signals, if present, are routed around the electronic circuit unmodified. The downlink signals are amplified, filtered, amplified again with a one or more peaking equalization amplifier, then amplified with drivers which provide the power to drive the downlink signal through a second mixer onto the UTP lines to the customer premises equipment. The electronic circuit separates the uplink signals from the downlink signals with the second mixer. The uplink signals are amplified, filtered, and amplified again, then driven onto the UTP connected with the central office through the first mixer.

Abstract: A DSL line conditioner achieves high performance sufficient to simultaneously support video, voice and data signals on standard telephone twisted pair lines over substantially greater distances than are currently available. The line conditioner automatically adjusts and sets the upstream and downstream preamplifier gains and attenuations according to the actual degradation imposed upon the upstream and downstream signals by the twisted pair line in which the line conditioner is used. The line conditioner achieves high performance by optimizing the signal-to-noise ratio and signal quality of DSL signals, and has a low power budget that enables it to operate by deriving power from the twisted pair lines over which it is used.

Abstract: An analog electronic circuit is placed between the central office of a telecommunications provider and the customer premises equipment of a digital subscriber line system which uses unshielded twisted pair wires (“UTP”). The electronic circuit separates the downlink signals from the uplink signals with a first mixer. The voice signals, if present, are routed around the electronic circuit unmodified. The downlink signals are amplified, filtered, amplified again with a one or more peaking equalization amplifier, then amplified with drivers which provide the power to drive the downlink signal through a second mixer onto the UTP lines to the customer premises equipment. The electronic circuit separates the uplink signals from the downlink signals with the second mixer. The uplink signals are amplified, filtered, and amplified again, then driven onto the UTP connected with the central office through the first mixer.