Intel Corporation

Seeq Technology, Incorporated

Lsi Logic Corporation

Lsi Logic Cororation

Seeo Technology, Incorporated

Robert X Jin

Stephen F Dreyer

Eric T West

Kathy L Peng

Lee-Chung Yiu

Hui Shi

Vivian Hu

A transmitting device to send an input signal in a channel includes an equalization system. The equalization system includes a decision subsystem to determine when adjustments need to be made based on the frequency of 0s or 1s in the input signal. The equalization system also includes an equalization subsystem to determine, by default, or by user choice, a compensation for a channel's amplitude variation due to frequency response, and to apply the compensation to the input signal and generate an equalized output signal.

Method and system for a fast serial transmit equalization scheme

Fast serial transmit equalization scheme

In accordance with one embodiment of the present invention, a signal detect circuit may analyze an input signal before passing it on to a receiver. The analysis may be done outside of the data path to avoid affecting the data path speed or adding distortion or jitter. The positive and negative thresholds of the data may be checked to see if the numbers of positive and negative crossings are comparable. Random and bursty noise can be detected since such noise normally does not have comparable positive and negative crossings.

Signal detect circuit for high speed data receivers

Resistors may be more accurately tuned by using an external resistor and comparing the value of an internal resistor to the value of the external resistor. The value of the internal resistor may be adjusted to match the value of the external resistor. Any number of on-chip resistors may then be matched and adjusted using the information obtained with respect to the first internal resistor.

Accurately tuning resistors

A bidirectional communications interface employs the same path for transmitting and receiving. The bidirectional communications interface includes one two winding transformer for both transmit and receive and an integrated circuit having a transmitter and a receiver each connected to the same pair of input/output pins. The interface enables a communications node in a communications network to transmit data to and receive data from other nodes in the network.

Bidirection channels using common pins for transmit and receive paths

In a 100BASE-T4 protocol network, the &ldquo;carrier_status&rdquo; signal associated with an incoming packet on a PMA of a given port of a Clause 27 repeater is obviated and a direct connection between PMAs and a Clause 27 repeater in the network is eliminated by transmitting synthetic preamble signals over the PMA-Repeater Data Interface to the Clause 27 repeater corresponding to the given port at an early time prior to the time that the actual preamble information of the packet is transmitted over that data interface. Receipt of the synthetic preamble signals causes the repeater to awaken and to repeat the synthetic preamble signals to other ports of the repeater. In turn, the other ports become quiet in anticipation of data to be repeated from the given port to the other ports of the repeater.

Method and apparatus for using synthetic preamble signals to awaken repeater

An apparatus and method for aligning any number of multiple parallel channels of data signals according to a single clock is provided. The synchronization process is accomplished through the use of a First-In-First-Out (FIFO) principle and individual storage elements implementing the FIFO principle for each received data channel. Each channel's data signals are read into a corresponding storage element, maintained in order, and read out upon the assertion of read signals in synchronization with a designated single clock signal. The apparatus and method preferably uses indications of data ready to be read from a storage element implementing the FIFO principle and the presence of a master clock signal to activate the reading of the data from the corresponding storage element. Therefore, each data channel is fully aligned with the master clock signal. The clock-data alignment function may be implemented for a 100BASE-T4 receiver.

Apparatus and method for providing multiple channel clock-data alignment

Bidirectional channels using common pins for transmit and receive paths

In a 100BASE-T4 protocol network, the 'carrier.sub.-- status' signal associated with an incoming packet on a PMA of a given port of a Clause 27 repeater is obviated and a direct connection between PMAs and a Clause 27 repeater in the network is eliminated by transmitting synthetic preamble signals over the PMA-Repeater Data Interface to the Clause 27 repeater corresponding to the given port at an early time prior to the time that the actual preamble information of the packet is transmitted over that data interface. Receipt of the synthetic preamble signals causes the repeater to awaken and to repeat the synthetic preamble signals to other ports of the repeater. In turn, the other ports become quiet in anticipation of data to be repeated from the given port to the other ports of the repeater.

Method and apparatus for using synthetic preamable signals to awaken

The present invention allows for the detection and correction of certain error conditions in packet-based data communications systems, including systems utilizing multiple channels or signal pairs, where all channels or signal pairs do not carry a link integrity signal or other repetitive non-data signal. A first aspect of the present invention provides detection and correction for reverse polarity. A second aspect of the present invention provides detection and correction for pair swap. A third aspect of the present invention provides a link integrity function. Detection of reverse polarity, detection of pair swap, and detection of link integrity utilizes the non-data components of received packets, either independently or in conjunction with a link integrity signal or other repetitive non-data signal. Reverse polarity is corrected by inverting the received signals prior to transmission or repetition to subsequent circuitry. Pair swap is corrected by switching the signals received on the swapped pairs prior to transmission or repetition to subsequent circuitry. Link integrity status is indicated via a transmitted signal.

Apparatus and method for detecting and correcting pair swap, and

The present invention allows for the detection and correction of certain error conditions in packet-based data communications systems, including systems utilizing multiple channels or signal pairs, where all channels or signal pairs do not carry a link integrity signal or other repetitive non-data signal. A first aspect of the present invention provides detection and correction for reverse polarity. A second aspect of the present invention provides detection and correction for pair swap. A third aspect of the present invention provides a link integrity function. Detection of reverse polarity, detection of pair swap, and detection of link integrity by utilizes the non-data components of received packets, either independently or in conjunction with a link integrity signal or other repetitive non-data signal. Reverse polarity is corrected by inverting the received signals prior to transmission or repetition to subsequent circuitry. Pair swap is corrected by switching the signals received on the swapped pairs prior to transmission or repetition to subsequent circuitry. Link integrity status is indicated via a transmitted signal.

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San Jose, CA, United States of America

Robert X Jin