Lucent Technologies Inc.

At&t Bell Laboratories

At+t Corp.

Attilio J Rainal

Venkataraman Swaminathan

Donald Barry Mellen

Eric A Hamilton

Jere C Shank

Jack P White

In a routing system where a router interconnects circuit components with conduction paths, a crosstalk analyzer is employed to audit the electrical crosstalk incurred in coupled path segments during the interconnection. The resulting crosstalk measures are compared with one or more acceptable crosstalk limits. If the measures exceed any limits, the unsatisfactory condition is fed back to the router, along with information on suggested re-arrangements of the segments. In response to this feedback, the router modifies the routed interconnections to reduce the crosstalk level.

Technique for effectively routing conduction paths in circuit layouts

A modular electrical connector assembly to which an electrical telecommunication cable is connectable for communicating electrical signals between the connector assembly and cable. The connector assembly includes an electrically nonconductive body and a crosstalk energy emitting electrical interference source on the body and/or on or proximate the connector assembly. Electrically conductive first and second leads on the body define an electrical signal circuit for carrying electrical signals communicatable with the cable. The first lead is located more closely proximate to the interference source than is the second lead such that a greater amount of crosstalk energy from the interference source is electromagnetically impressed on the first lead than on the second lead to thereby define a difference in crosstalk energy on the first and second leads. A parasitic sized RF chip capacitor connects the interference source to the second lead for transferring crosstalk energy therethrough in an amount sufficient to substantially equalize crosstalk energy on the first and second leads and thereby reduce crosstalk-induced interference in the electrical signal circuit. In this manner and existing Category 3 connector assembly (10 Mbs) is transformed into a Category 5 connector assembly (100 Mbs) for use with signal transmission by optical fiber to buildings and the like.

Low-crosstalk modular electrical connector assembly

A system and method for predicting the ratio of the strength of the carrier signal to the strength of nonlinear distortion (C/NLD) generated by a communications laser is disclosed. The method jointly evaluates the individual distortion components arising from laser clipping and from inherent laser P-I nonlinearity. According to the method, the laser P-I curve is measured with high precision to quantify the P-I nonlinearity. Various derivatives of the P-I curve are determined and then utilized to calculate C/NLD as a function of a communications network parameter such as the optical modulation index per channel or rms modulation index. Based on this information, the laser can be identified in terms of its sensitivity to RF drive variations in the field. Lasers can be tagged, etc., depending on their C/NLD sensitivity. In this manner, a laser having a C/NLD ratio appropriate for the requirements of a broadband transmission network, such as a SCM CATV system, can be selected and installed in such a system.

System and methods for assessing the suitability of analog lasers for

An amplitude limiting circuit is utilized to select the most favorable linear region of the light vs. current characteristic curve (for directly modulated lasers) or the lasers modulator transfer function (for externally modulated lasers) by preventing excursions of the broadband, multiplexed input signal beyond selected upper and lower current or voltage limits. The clipped broadband signal is represented as a stationary Gaussian process to provide a reliable estimate of the carrier-to-nonlinear distortion per channel that would be experienced with a given laser or optical modulator which may be either directly and externally modulated. The clipping levels can be set to avoid the unpredictable levels of nonlinear distortion of the modulator and thereby to achieve an acceptably low level of non-linear distortion of the modulator.

System and method for minimizing nonlinear distortion in optical

An integrated circuit output section has a controller that controls a plurality of drivers to transmit data signals over output lines in a group staggered manner to substantially reduce the generation of inductive noise or ground and power bounce. The controller staggers the transmission of the data signals in each group relative to the other groups to achieve a reduction in inductive noise of greater than 25% using relatively short total staggering times of less than five times the transition switching time of a driver for the groups of data signals. Also, an enhanced reduction in inductive noise is achieved with a total staggering time equal to or less than a driver transition switching time, wherein at least one group has a different number of data signals than the other groups.

Integrated circuit having reduced inductive noise

A balanced driver circuit which essentially eliminates inductive noise without a power dissipation penalty is disclosed. The balanced driver circuit is similar to a conventional balanced driver circuit however the circuit is impedance matched at both ends and has resistors connected in series with the outputs of the emitter followers in the chip. The resistors are equal in value to a termination resistor less the output impedance of the emitter followers. The impedance between the pair of signal leads, referred to as the primary and secondary leads is equal to the sum of the termination resistors. The current traversing the secondary lead has the same amplitude, but the opposite sign as the current traversing the primary lead. Thus, there is negligible current return through the common ground leads.

Balanced driver circuit for eliminating inductive noise

A tool for designing the conductors into a PWB includes an audit arrangement for auditing or analyzing crosstalk between electrical conductors to be entered into the PWB. This crosstalk audit may be performed as soon as the initial design is created and before actual manufacture of the PWB. It is operative to identify crosstalk problem areas and to identify impedance mismatches. In particular the audit process defines conduction paths into conduction nets conduction nets are selected one at a time for evaluation and simulated as having an idle current condition. Nearby conduction nets are simulated as being driven in an active condition. The response of the idle network is used to derive a plurality of crosstalk parameters which are used to determine the crosstalk effect on the net under test.

Process and apparatus for auditing crosstalk and characteristic

Ground noise associated with lead inductance in electronic systems containing multiple lead integrated circuits is substantially reduced by including, for each chip driver lead that carries a signal, a complementary lead which carries the the inverse of that signal. These balanced pairs are continued not only in the wire bonds and lead frame of the integrated circuit, but also through any connecting assembly such as a printed wiring board or multichip module to the associated balanced chip receivers.

Balanced circuitry for reducing inductive noise of external chip

By on-chip modification of a conventional balanced driver to yield special voltage levels, the power dissipation of a balanced, terminated transmission line circuit can be reduced by 50% or more relative to a conventional balanced driver or 25% or more relative to a conventional unbalanced driver. This reduction in power dissipation not only applies to point-to-point interconnections but also applies to bused interconnections. The low power balanced driver circuit can be implemented using ECL, BiCMOS, GaAs and CMOS technologies and no modifications are needed to the associated differential line receiver. Thus, the significant benefits of balanced interconnections, namely reduced crosstalk, increased noise immunity, and elimination of ground noise can be realized with a significant reduction in power dissipation.

Article comprising a balanced driver circuit with less power dissipation

A high-speed, high pin-out chip carrier package (10) for interconnecting at least one LSI or VLSI chip to a circuit pack is disclosed. The package includes a ground plane (19), a power plane (20), and at least one signal layer (15, 16, 17, 18) containing plural conductors therethrough. Layers (85) of dielectric material separate adjacent conductive layers, (15, 16, 17, 18, 19, 20). By controlling, in design, the width of each signal conductor and its distance to the nearest ground (19) or power plane (20), the package is impedance-matched to the circuit pack. Plural plated-through holes (21) are disposed through the package for electrically interconnecting the signal conductors, the ground plane (19), and the power plane (20) to the circuit pack, and are arranged in a pattern to reduce inductive noise.

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Morristown, NJ, United States of America

Attilio J Rainal