Lucent Technologies Inc.

Agere Systems Inc.

Mingjie Wang

Herbert B Cohen

Lujing Cai

Richard Rogoszewicz

A system for, and method of recovering primary channel operation in a facsimile (fax) receiver and a fax machine that incorporates the system, the method or both. In one embodiment, the system includes: (1) a signal receiver that receives a signal containing first and second points located at first and second angles and (2) angle determination circuitry that determines an offset angle by which the signal has been rotated based on the first and second angles.

System and method for recovering primary channel operation in a facsimile receiver and facsimile machine incorporating the same

A modem monitor for monitoring full duplex communications comprises one receiver for each data stream and an echo canceler for canceling 'far' echo. Prior to each receiver decoding the data stream it is designed to monitor, it replicates an echo expected to be found in its received data stream from a sample of each of the other predecoded data streams. The echo canceler then subtracts the expected echo from the received data stream to remove all far echoes caused by the other data streams. The echo canceled data stream is then decoded. The monitor can also include a data communications network interface and a sample rate converter operating with the PSTN for converting from the network transmission rate to the data transmission rate.

Apparatus and method for monitoring full duplex data communications

Apparatus, system, and method is disclosed for digitally processing a signal for reduced distortion and frequency deviation. The digital processor involves increasing the sampling frequency of a digital signal prior to a non-linear operating stage. The processed signal is then passed through a low pass filter prior to being down-converted to the initial sampling frequency. Thus, a signal can be digitally processed for reduced distortion as well as reduced frequency deviation.

Digital processor for reduced distortion and frequency deviation

A method is presented to enable high speed transmission in the upstream channel from a customer's modem to a PCM modem connected to the public switched digital network. The upstream channel is equalized by having the client modem send a known training sequence in the upstream direction to the server modem. The server modem calculates the cross-correlation between the known training sequence and the sequence as actually received from the client modem. The cross-correlation is then multiplied by the known auto-correlation of the training sequence to produce a model of the channel response. The channel response is then reported to the client modem so that it may adjust its pre-equalizer to construct the signal that the client modem will thereafter send in the upstream direction.

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Eatontown, NJ, United States of America

Mingjie Wang