Lucent Technologies Inc.

Agere Systems Guardian Corp.

Vahid Marandi

Mohammad Shafiul Mobin

Cecil William Farrow

Kalyan Mondal

Daniel J Udovic

Akkas T Sufi

Kaylan Mondal

Kai-Chuen Wong

A QAM data signal timing recovery loop feedback element provides a fixed sampling time offset adjustment to two continuously variable digital rate interpolators/decimators to produce a quadrature output stream at a programmed rational rate multiple of the actual baud rate of the received data signal. The continuously variable digital rate interpolators/decimators are configured at startup so as to produce output streams at the same programmed rational rate multiple of the nominal baud rate of the anticipated received data signal, assuming the fs sample timing offset adjustment stream provided by the timing recovery feedback element to be identically 0. The &ldquo;nominal&rdquo; fixed sampling rate fs of the received analog input signal need not be rationally related to the nominal baud rate of the anticipated received data signal.

Fixed clock based arbitrary symbol rate timing recovery loop

A digital automatic gain control circuit for a receiver includes an averaging block and an adjustment block. The averaging block receives a length of a digital sample stream that represents an incoming analog signal and produces an absolute average signal. The adjustment block receives the absolute average signal and a reference signal and outputs an adjustment signal for controlling gain. The adjustment signal is based on a difference between the absolute average signal and the reference signal. In an alternative embodiment, a method of controlling gain according to the invention includes the steps of calculating an absolute average of an incoming signal, and comparing the absolute average to a reference to produce an adjustment signal based on a difference between the absolute average and the reference.

Amplitude based coarse automatic gain control circuit

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Mission Viejo, CA, United States of America

Vahid Marandi