Brooktree Broadband Holding, Inc.

Globespan Virata Corporation

Conexant, Inc.

Globespan, Inc.

Christian Eichrodt

Arnold Muralt

Frode Larsen

Nianxiong Tan

Brian Horng

James J Zhao

Francis M Caster, Ii

A system and a method for constructing a signal integrity supervisor capable of both detecting and triggering an appropriate response when transmit path signals indicate a potential damaging transmitter operating mode. The system and method of the present invention takes advantage of the inherent property of a Delta-Sigma Modulator (DSM) which makes the probability of encountering a long string of consecutive ones or zeroes during nominal operation very small. The signal integrity supervisor ensures safe transmitter operation by monitoring the data and the clock inputs to a digital to analog converter. The system may comprise a data signal supervisor and a clock signal supervisor. The data supervisor may comprise a comparator and a counter and may be configured to power down a line driver upon detecting a data stream having a continuous voltage level. The clock detector may comprise a pair of monostable circuits, an inverter, and a NAND gate and may be configured to reset the transmitter if a 'missing' clock signal state is detected. The present invention can also be viewed as providing a method for preventing a transmission unit from forwarding signals that may result in a DC flow condition. In its broadest terms, the method can be described as: monitoring a data signal; generating a first output signal in response to a data signal having an anomalous condition; monitoring a clock signal; and generating a second output signal in response to clock signal having an anomalous condition.

System and method for implementing a delta-sigma modulator integrity supervisor

An analog front-end circuit and method that supports multiple digital subscriber line (DSL) standards, including asymmetric digital subscriber line (ADSL) and very-high speed digital subscriber line (VDSL) is disclosed. The circuit incorporates multiple circuit blocks that can be selectively included into the transmit and receive paths of a DSL signal. It also permits selectable gain settings for signal amplifiers, and frequency bandwidth for signal filters that may be included in the transmit and receive paths. The receive path includes an analog-to-digital converter (ADC) that operates close to and exceeds the Nyquist sampling rate.

Wide-band analog front-end for DSL applications

A single unified digital subscriber line (DSL) transceiver can be used for DSL applications, can be integrated on a single board or chip, or within a less board space. An embodiment of the unified DSL transceiver comprises a transmit circuit coupled to a line driver/transformer circuit. The line driver/transformer circuit is coupled to a receive circuit that comprises a switching circuit. A signal is transmitted from the transmit circuit to the line driver/transformer circuit; the switching circuit is configured based on DSL applications, and the signal is propagated from the line driver/transformer circuit to a line.

Unified DSL transceiver

A system and a method for constructing a signal integrity supervisor capable of both detecting and triggering an appropriate response when transmit path signals indicate a potential damaging transmitter operating mode. The system and method of the present invention takes advantage of the inherent property of a Delta-Sigma Modulator (DSM) which makes the probability of encountering a long string of consecutive ones or zeroes during nominal operation very small. The signal integrity supervisor ensures safe transmitter operation by monitoring the data and the clock inputs to a digital to analog converter. The system may comprise a data signal supervisor and a clock signal supervisor. The data supervisor may comprise a comparator and a counter and may be configured to power down a line driver upon detecting a data stream having a continuous voltage level. The clock detector may comprise a pair of monostable circuits, an inverter, and a NAND gate and may be configured to reset the transmitter if a &ldquo;missing&rdquo; clock signal state is detected. The present invention can also be viewed as providing a method for preventing a transmission unit from forwarding signals that may result in a DC flow condition. In its broadest terms, the method can be described as: monitoring a data signal; generating a first output signal in response to a data signal having an anomalous condition; monitoring a clock signal; and generating a second output signal in response to clock signal having an anomalous condition.

Growing community of inventors

Tustin, CA, United States of America

Christian Eichrodt