Dsc Communications Corporation

Alcatel USA

Oscar A Tovar

Charles C Eckhoff

David Matthew Smith

A redundancy switch (44) provides interfacing of network signals to spare network processors (46) in the event of a failure of a main network processor (42). A redundancy switch (44) allows for monitoring and diagnostic operations to be performed on network electrical signals without interrupting traffic flow on inbound and outbound paths. A redundancy switch (44) performs a loopback diagnostic by routing signals from transmitter portions of the spare network processors (46) to selected receiver portions. The redundancy switch (44) includes a receiver interface unit (90) and a transmitter interface unit (92) capable of routing inbound and outbound customer signals to and from the spare processors (46) for monitoring, diagnostic, and sparing purposes.

Signal protection and monitoring system

An adaptive cable equalizer (10) includes an input section (12) that receives a radio frequency electrical signal from a cable (14). The input section (12) provides the electrical signal to an equalizing amplifier section (16) that controls an amount of current flow of the electrical signal to an equalizing controller (18). The equalizing controller (18) generates an equalized output signal (21) through a voltage drop which is proportional to a roll-off distortion of the cable (14). The voltage drop is processed by an amplifier (80) and a line receiver (88) to reconstruct the electrical signal in a digital representation of the equalized output signal (21). The voltage drop is also fed to a detector (20) that generates a control signal (23) and a bias signal (25) to adjust the conductivity of the equalizing amplifier section (16). In this manner, adjustments are automatically made in order to provide the equalized output signal (21) regardless of the characteristics of the cable (14).

Adaptive cable equalizer

A high speed signal transport system (10) provides data transmission across a balanced channel (14). The balanced channel (14) carries differential signals from the output of a differential transmitter (12). An equalizer (18) compensates for distortion in the balanced channel in order to reduce timing jitter of the signal. The signal is applied to the input of a differential receiver (20) which exploits the precise quantization threshold inherent in differential data to accurately convert the signal to digital data. The differential receiver (20) also employs a known frequency reference along with digital transition detection to rephase the digital data to the local clock. No duty-cycle limitation is placed on the signal carried by the balanced channel (14) and therefore the differential transmitter (12) and differential receiver (20) are not required to encode the signal. Because the signal-to-noise ratio seen by the differential receiver (20) is ample for accurate quantization, the equalizer (18) is optimized for jitter reduction in order to obviate the need for analog retiming circuits.

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Plano, TX, United States of America

Oscar A Tovar