Oscar Eduardo Tovar

US Patent:

56990227, Dec 16, 1997

Filed:

Feb 9, 1996

Appl. No.:

8/598814

Inventors:

Oscar A. Tovar - Plano TX

Assignee:

DSC Communications Corporation - Plano TX

International Classification:

H04B 304

US Classification:

333 18

Abstract:

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).

US Patent:

58963707, Apr 20, 1999

Filed:

Nov 12, 1996

Appl. No.:

8/748202

Inventors:

Charles C. Eckhoff - Plano TX
Oscar A. Tovar - Plano TX

Assignee:

Alcatel USA, Inc. - Plano TX

International Classification:

H04J 314

US Classification:

370228

Abstract:

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.

US Patent:

55747183, Nov 12, 1996

Filed:

Jul 1, 1994

Appl. No.:

8/270019

Inventors:

Charles C. Eckhoff - Plano TX
Oscar A. Tovar - Plano TX

Assignee:

DSC Communications Corporation - Plano TX

International Classification:

H04J 116

US Classification:

370 16

Abstract:

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.

US Patent:

56087578, Mar 4, 1997

Filed:

Jun 3, 1994

Appl. No.:

8/253339

Inventors:

David M. Smith - Plano TX
Oscar A. Tovar - Plano TX

Assignee:

DSC Communications Corporation - Plano TX

International Classification:

H03H 730

US Classification:

375229

Abstract:

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.