Geoffrey J Zhang, 645943 Garlough Dr, San Jose, CA 95123

7882404, Feb 1, 2011

Nov 6, 2007

11/935759

Xingdong Dai - Bethleham PA, US
Geoffrey Zhang - Allentown PA, US
Max J. Olsen - Mertztown PA, US

Agere Systems Inc. - Allentown PA

G01R 31/28

714716, 714717

The present invention implements a method and apparatus for using components within a Serializer/DeSerializer (SerDes) to emulate the effects of a backplane in order to facilitate automated test equipment (ATE) testing of the SerDes. The SerDes includes a transmitter pre-emphasis circuit (TPXE) that pre-emphasizes a transmitted signal and a receiver equalization circuit (RXEQ) that equalizes a received signal. The TPXE includes coefficients that are dynamically programmable.

8040984, Oct 18, 2011

Dec 31, 2007

11/967602

Pervez M. Aziz - Dallas TX, US
Adam B. Healey - Newburyport MA, US
Mohammad S. Mobin - Orefield PA, US
Gary E. Schiessler - Allentown PA, US
Gregory W. Sheets - Breinigsville PA, US
Lane A. Smith - Easton PA, US
Paul H. Tracy - Lehigh PA, US
Geoffrey Zhang - Allentown PA, US

Agere System Inc. - Allentown PA

H04L 25/08
H04L 7/10
H04L 7/00

375346, 375345, 375371

Methods and apparatus are provided for improving the jitter tolerance in an SFP limit amplified signal. Jitter tolerance is improved in a communications receiver by applying a received signal to an SFP limiting amplifier; and applying an output of the SFP limiting amplifier to a low pass filter to improve the jitter tolerance. The low pass filter optionally applies a programmable amount of attenuation to high frequency components of the output. The low pass filter slew rate controls (i. e. , rotates) a data eye representation of the received signal to increase the data eye representation along a time axis. The noise margin of the received signal can optionally be improved by applying an output of the low pass filter to an all pass filter. A slew rate controller can evaluate the data eye statistics to determine a setting for the low pass filter.

8125259, Feb 28, 2012

Jan 3, 2008

11/968942

Xingdong Dai - Bethlehem PA, US
Weiwei Mao - Macungie PA, US
Max J. Olsen - Mertztown PA, US
Geoffrey Zhang - Allentown PA, US

Agere Systems Inc. - Allentown PA

H03K 3/017

327175, 375375

A method and system for modeling and calibrating duty cycle distortion (DCD) of a Serializer and Deserializer (SerDes) device, including first generating a clock DCD signal. Once the clock DCD signal is generated, it is calibrating based upon results obtained from a filtering process of the clock DCD signal. Once the clock DCD signal is calibrated, a data DCD signal is generated and calibrated based upon results obtained from a filtering process of the data DCD signal.

8243868, Aug 14, 2012

Dec 31, 2007

12/006180

Geoffrey Zhang - Allentown PA, US
Xingdong Dai - Bethlehem PA, US

Agere Systems Inc. - Allentown PA

H04L 7/00

375371

In serial communications, jitter is an unwanted variation of one or more signal characteristics. Two-dimensional modulation circuits and methods incorporate an amplitude pre-emphasis scheme as well as a transmit duty cycle pre-distortion (pre-DCD) technique to reduce jitter. The pre-DCD technique directly addresses transition edges of the data signal and is combined with amplitude pre-emphasis to improved data transmission.

8514925, Aug 20, 2013

Jul 23, 2008

12/178301

Xingdong Dai - Whitehall PA, US
Dwight D. Daugherty - Ephrata PA, US
Max J. Olsen - Mertztown PA, US
Geoffrey Zhang - Allentown PA, US

Agere Systems LLC - Allentown PA

H03H 7/30

375233, 375229, 375230, 375232, 375235

Methods and apparatus are provided for joint adaptation of filter values in two communicating devices, such as a link partner and a link device. The disclosed joint adaptation process initially adapts the filter coefficient values in a first of the two communicating devices until a predefined stopping criteria is satisfied. Thereafter, the filter coefficient values in a second of the two communicating devices are adapted once the predefined stopping criteria for the first communicating device is satisfied. The filter coefficient values can comprise coefficient values of a multi-tap filter. The predefined stopping criteria may determine, for example, whether the first of the two communicating devices is overequalized. The filter coefficient values can be determined by including a contribution of only certain cursor tap values of the channel impulse response.

8559580, Oct 15, 2013

Jun 30, 2009

12/494771

Xingdong Dai - Whitehall PA, US
Dwight David Daugherty - Ephrata PA, US
Max J. Olsen - Mertztown PA, US
Lane A. Smith - Easton PA, US
Geoffrey Zhang - Allentown PA, US

LSI Corporation - San Jose CA

H04L 7/00
H04L 25/00
H04L 25/40

375371, 375354

Techniques are disclosed for asynchronous calibration for eye diagram generation. For example, a method for calibrating a process for generating a data eye associated with a received signal comprises the following steps. Samples of the received signal are obtained for a first unit interval using a first data latch and a roaming latch. A delay offset is determined between the first data latch and the roaming latch by comparing at least one sample obtained using the first data latch and at least one sample obtained using the roaming latch, wherein the delay offset determined by the comparison is used to calibrate the process for generating the data eye associated with the received signal. A similar comparison may be done for a second data latch and used to calibrate the process. The method is able to find the accurate position of each data latch with respect to the roaming latch so as to improve the accuracy of data decoding in a digital receiver, i. e. , provide receiver optimization.

8611406, Dec 17, 2013

Jun 30, 2009

12/494805

Xingdong Dai - Whitehall PA, US
Max J. Olsen - Mertztown PA, US
Scott A. Werner - Wernersville PA, US
Geoffrey Zhang - Allentown PA, US

LSI Corporation - San Jose CA

H04B 3/46
H04B 17/00
H04Q 1/20

375224

Communication system optimization using a soft receiver masking technique is disclosed. For example, a method for testing a communication device comprises obtaining a software representation of a receiver portion of a given communication device. A data signal received from a transmitter through a given link channel is then processed, wherein the processing step is performed using the software representation of the receiver portion of the communication device. An output signal is caused to be generated by the software representation of the receiver portion. An eye mask test is then applied to the output signal. Based on a result of the eye mask test, one or more parameters of the transmitter may be adjusted.

8045608, Oct 25, 2011

Jul 30, 2008

12/221002

Xingdong Dai - Whitehall PA, US
Geoffrey Zhang - Allentown PA, US
Max Olsen - Mertztown PA, US
Dwight Daugherty - Ephrata PA, US
Gary Schiessler - Allentown PA, US
Mohammad Mobin - Orefield PA, US
Lane Smith - Easton PA, US
Dennis Farley - Coopersburg PA, US

Agere Systems Inc. - Allentown PA

H03H 7/30

375232, 375233, 375348, 375349, 370222

In described embodiments, an adaptive equalizer employed by a receiver in a communication channel, such as Fibre Channel, employs pattern recognition. When a repeating pattern, such as an IDLE or ARBFF pattern, is employed by a standard to, for example, maintain a communication link, an equalizer of the receiver might adaptively set its equalizer parameters based on characteristics of the signal energy of the repeating pattern rather than adaptively set its equalizer parameters based on characteristics of the signal energy of generally random user data carried on the link. Pattern recognition by the receiver allows for maintaining adaptive equalizer parameters at settings preferred for data detection of the typical random data, improving data detection performance of the receiver when the channel transitions from a preset or synchronization repeating pattern to a user random data pattern.